[ Upstream commit 8e62bf2bfa ]
Linux guests since commit b1c3497e60 ("x86/xen: Add support for
HVMOP_set_evtchn_upcall_vector") in v6.0 onwards will use the per-vCPU
upcall vector when it's advertised in the Xen CPUID leaves.
This upcall is injected through the guest's local APIC as an MSI, unlike
the older system vector which was merely injected by the hypervisor any
time the CPU was able to receive an interrupt and the upcall_pending
flags is set in its vcpu_info.
Effectively, that makes the per-CPU upcall edge triggered instead of
level triggered, which results in the upcall being lost if the MSI is
delivered when the local APIC is *disabled*.
Xen checks the vcpu_info->evtchn_upcall_pending flag when the local APIC
for a vCPU is software enabled (in fact, on any write to the SPIV
register which doesn't disable the APIC). Do the same in KVM since KVM
doesn't provide a way for userspace to intervene and trap accesses to
the SPIV register of a local APIC emulated by KVM.
Fixes: fde0451be8 ("KVM: x86/xen: Support per-vCPU event channel upcall via local APIC")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240227115648.3104-3-dwmw2@infradead.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d54e56f31a ]
Commit 344da544f1 ("x86/nmi: Print reasons why backtrace NMIs are
ignored") creates a super nice framework to diagnose NMIs.
Every time nmi_exc() is called, it increments a per_cpu counter
(nsp->idt_nmi_seq). At its exit, it also increments the same counter. By
reading this counter it can be seen how many times that function was called
(dividing by 2), and, if the function is still being executed, by checking
the idt_nmi_seq's least significant bit.
On the check side (nmi_backtrace_stall_check()), that variable is queried
to check if the NMI is still being executed, but, there is a mistake in the
bitwise operation. That code wants to check if the least significant bit of
the idt_nmi_seq is set or not, but does the opposite, and checks for all
the other bits, which will always be true after the first exc_nmi()
executed successfully.
This appends the misleading string to the dump "(CPU currently in NMI
handler function)"
Fix it by checking the least significant bit, and if it is set, append the
string.
Fixes: 344da544f1 ("x86/nmi: Print reasons why backtrace NMIs are ignored")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240207165237.1048837-1-leitao@debian.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2b4b90e053 ]
Currently, the secondary CPUs in Hyper-V VTL context lack support for
parallel startup. Therefore, relying on the single initial_stack fetched
from the current task structure suffices for all vCPUs.
However, common initial_stack risks stack corruption when parallel startup
is enabled. In order to facilitate parallel startup, use the initial_stack
from the per CPU idle thread instead of the current task.
Fixes: 3be1bc2fe9 ("x86/hyperv: VTL support for Hyper-V")
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ad8c91282c ]
When bringing a CPU online, some of the PMC and LBR related registers
are reset. The same is done when a CPU is taken offline although that
is unnecessary. This currently happens in the "cpu_dead" callback which
is also incorrect as the callback runs on a control CPU instead of the
one that is being taken offline. This also affects hibernation and
suspend to RAM on some platforms as reported in the link below.
Fixes: 21d59e3e2c ("perf/x86/amd/core: Detect PerfMonV2 support")
Reported-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/550a026764342cf7e5812680e3e2b91fe662b5ac.1706526029.git.sandipan.das@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a51ab63b29 ]
As there are some AMD processors which only support CPPC V2 firmware and
BIOS implementation, the amd_pstate driver will be failed to load when
system booting with below kernel warning message:
[ 0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled
To make the amd_pstate driver can be loaded on those TR40 processors, it
needs to match x86_model from 0x30 to 0x7F for family 17H.
With the change, the system can load amd_pstate driver as expected.
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reported-by: Gino Badouri <badouri.g@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218171
Fixes: fbd74d1689 ("ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory")
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit aaa8736370 ]
When building with CONFIG_XEN_PV=y, .text symbols are emitted into
the .notes section so that Xen can find the "startup_xen" entry point.
This information is used prior to booting the kernel, so relocations
are not useful. In fact, performing relocations against the .notes
section means that the KASLR base is exposed since /sys/kernel/notes
is world-readable.
To avoid leaking the KASLR base without breaking unprivileged tools that
are expecting to read /sys/kernel/notes, skip performing relocations in
the .notes section. The values readable in .notes are then identical to
those found in System.map.
Reported-by: Guixiong Wei <guixiongwei@gmail.com>
Closes: https://lore.kernel.org/all/20240218073501.54555-1-guixiongwei@gmail.com/
Fixes: 5ead97c84f ("xen: Core Xen implementation")
Fixes: da1a679cde ("Add /sys/kernel/notes")
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5bdd181821 ]
Commit e56d28df2f ("x86/virt/tdx: Configure global KeyID on all
packages") causes a sparse warning:
arch/x86/virt/vmx/tdx/tdx.c:683:27: warning: incorrect type in argument 1 (different address spaces)
arch/x86/virt/vmx/tdx/tdx.c:683:27: expected void [noderef] __iomem *dst
arch/x86/virt/vmx/tdx/tdx.c:683:27: got void *
The reason is TDX must use the MOVDIR64B instruction to convert TDX
private memory (which is normal RAM but not MMIO) back to normal. The
TDX code uses existing movdir64b() helper to do that, but the first
argument @dst of movdir64b() is annotated with __iomem.
When movdir64b() was firstly introduced in commit 0888e1030d
("x86/asm: Carve out a generic movdir64b() helper for general usage"),
it didn't have the __iomem annotation. But this commit also introduced
the same "incorrect type" sparse warning because the iosubmit_cmds512(),
which was the solo caller of movdir64b(), has the __iomem annotation.
This was later fixed by commit 6ae58d8713 ("x86/asm: Annotate
movdir64b()'s dst argument with __iomem"). That fix was reasonable
because until TDX code the movdir64b() was only used to move data to
MMIO location, as described by the commit message:
... The current usages send a 64-bytes command descriptor to an MMIO
location (portal) on a device for consumption. When future usages for
the MOVDIR64B instruction warrant a separate variant of a memory to
memory operation, the argument annotation can be revisited.
Now TDX code uses MOVDIR64B to move data to normal memory so it's time
to revisit.
The SDM says the destination of MOVDIR64B is "memory location specified
in a general register", thus it's more reasonable that movdir64b() does
not have the __iomem annotation on the @dst.
Remove the __iomem annotation from the @dst argument of movdir64b() to
fix the sparse warning in TDX code. Similar to memset_io(), introduce a
new movdir64b_io() to cover the case where the destination is an MMIO
location, and change the solo caller iosubmit_cmds512() to use the new
movdir64b_io().
In movdir64b_io() explicitly use __force in the type casting otherwise
there will be below sparse warning:
warning: cast removes address space '__iomem' of expression
[ dhansen: normal changelog tweaks ]
Closes: https://lore.kernel.org/oe-kbuild-all/202312311924.tGjsBIQD-lkp@intel.com/
Fixes: e56d28df2f ("x86/virt/tdx: Configure global KeyID on all packages")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/all/20240126023852.11065-1-kai.huang%40intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e814b59e6c ]
Commit
cbebd68f59 ("x86/mm: Fix use of uninitialized buffer in sme_enable()")
'fixed' an issue in sme_enable() detected by static analysis, and broke
the common case in the process.
cmdline_find_option() will return < 0 on an error, or when the command
line argument does not appear at all. In this particular case, the
latter is not an error condition, and so the early exit is wrong.
Instead, without mem_encrypt= on the command line, the compile time
default should be honoured, which could be to enable memory encryption,
and this is currently broken.
Fix it by setting sme_me_mask to a preliminary value based on the
compile time default, and only omitting the command line argument test
when cmdline_find_option() returns an error.
[ bp: Drop active_by_default while at it. ]
Fixes: cbebd68f59 ("x86/mm: Fix use of uninitialized buffer in sme_enable()")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240126163918.2908990-2-ardb+git@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c2427e70c1 ]
The mba_MBps feedback loop increases throttling when a group is using
more bandwidth than the target set by the user in the schemata file, and
decreases throttling when below target.
To avoid possibly stepping throttling up and down on every poll a flag
"delta_comp" is set whenever throttling is changed to indicate that the
actual change in bandwidth should be recorded on the next poll in
"delta_bw". Throttling is only reduced if the current bandwidth plus
delta_bw is below the user target.
This algorithm works well if the workload has steady bandwidth needs.
But it can go badly wrong if the workload moves to a different phase
just as the throttling level changed. E.g. if the workload becomes
essentially idle right as throttling level is increased, the value
calculated for delta_bw will be more or less the old bandwidth level.
If the workload then resumes, Linux may never reduce throttling because
current bandwidth plus delta_bw is above the target set by the user.
Implement a simpler heuristic by assuming that in the worst case the
currently measured bandwidth is being controlled by the current level of
throttling. Compute how much it may increase if throttling is relaxed to
the next higher level. If that is still below the user target, then it
is ok to reduce the amount of throttling.
Fixes: ba0f26d852 ("x86/intel_rdt/mba_sc: Prepare for feedback loop")
Reported-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Xiaochen Shen <xiaochen.shen@intel.com>
Link: https://lore.kernel.org/r/20240122180807.70518-1-tony.luck@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 54e35eb861 ]
If the BMEC (Bandwidth Monitoring Event Configuration) feature is
supported, the bandwidth events can be configured. The maximum supported
bandwidth bitmask can be read from CPUID:
CPUID_Fn80000020_ECX_x03 [Platform QoS Monitoring Bandwidth Event Configuration]
Bits Description
31:7 Reserved
6:0 Identifies the bandwidth sources that can be tracked.
While at it, move the mask checking to mon_config_write() before
iterating over all the domains. Also, print the valid bitmask when the
user tries to configure invalid event configuration value.
The CPUID details are documented in the Processor Programming Reference
(PPR) Vol 1.1 for AMD Family 19h Model 11h B1 - 55901 Rev 0.25 in the
Link tag.
Fixes: dc2a3e8579 ("x86/resctrl: Add interface to read mbm_total_bytes_config")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/669896fa512c7451319fa5ca2fdb6f7e015b5635.1705359148.git.babu.moger@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0976783bb1 ]
The QOS Memory Bandwidth Enforcement Limit is reported by
CPUID_Fn80000020_EAX_x01 and CPUID_Fn80000020_EAX_x02:
Bits Description
31:0 BW_LEN: Size of the QOS Memory Bandwidth Enforcement Limit.
Newer processors can support higher bandwidth limit than the current
hard-coded value. Remove latter and detect using CPUID instead. Also,
update the register variables eax and edx to match the AMD CPUID
definition.
The CPUID details are documented in the Processor Programming Reference
(PPR) Vol 1.1 for AMD Family 19h Model 11h B1 - 55901 Rev 0.25 in the
Link tag below.
Fixes: 4d05bf71f1 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/c26a8ca79d399ed076cf8bf2e9fbc58048808289.1705359148.git.babu.moger@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8e5647a723 ]
On 64-bit platforms, the pfn_to_kaddr() macro requires that the input
value is 64 bits in order to ensure that valid address bits don't get
lost when shifting that input by PAGE_SHIFT to calculate the physical
address to provide a virtual address for.
One such example is in pvalidate_pages() (used by SEV-SNP guests), where
the GFN in the struct used for page-state change requests is a 40-bit
bit-field, so attempts to pass this GFN field directly into
pfn_to_kaddr() ends up causing guest crashes when dealing with addresses
above the 1TB range due to the above.
Fix this issue with SEV-SNP guests, as well as any similar cases that
might cause issues in current/future code, by using an inline function,
instead of a macro, so that the input is implicitly cast to the
expected 64-bit input type prior to performing the shift operation.
While it might be argued that the issue is on the caller side, other
archs/macros have taken similar approaches to deal with instances like
this, such as ARM explicitly casting the input to phys_addr_t:
e48866647b ("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()")
A C inline function is even better though.
[ mingo: Refined the changelog some more & added __always_inline. ]
Fixes: 6c32117963 ("x86/sev: Add SNP-specific unaccepted memory support")
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231122163700.400507-1-michael.roth@amd.com
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2a0180129d upstream.
Mitigation for RFDS requires RFDS_CLEAR capability which is enumerated
by MSR_IA32_ARCH_CAPABILITIES bit 27. If the host has it set, export it
to guests so that they can deploy the mitigation.
RFDS_NO indicates that the system is not vulnerable to RFDS, export it
to guests so that they don't deploy the mitigation unnecessarily. When
the host is not affected by X86_BUG_RFDS, but has RFDS_NO=0, synthesize
RFDS_NO to the guest.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8076fcde01 upstream.
RFDS is a CPU vulnerability that may allow userspace to infer kernel
stale data previously used in floating point registers, vector registers
and integer registers. RFDS only affects certain Intel Atom processors.
Intel released a microcode update that uses VERW instruction to clear
the affected CPU buffers. Unlike MDS, none of the affected cores support
SMT.
Add RFDS bug infrastructure and enable the VERW based mitigation by
default, that clears the affected buffers just before exiting to
userspace. Also add sysfs reporting and cmdline parameter
"reg_file_data_sampling" to control the mitigation.
For details see:
Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e95df4ec0c upstream.
Currently MMIO Stale Data mitigation for CPUs not affected by MDS/TAA is
to only deploy VERW at VMentry by enabling mmio_stale_data_clear static
branch. No mitigation is needed for kernel->user transitions. If such
CPUs are also affected by RFDS, its mitigation may set
X86_FEATURE_CLEAR_CPU_BUF to deploy VERW at kernel->user and VMentry.
This could result in duplicate VERW at VMentry.
Fix this by disabling mmio_stale_data_clear static branch when
X86_FEATURE_CLEAR_CPU_BUF is enabled.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY to
avoid creating an inconsistent ABI (KVM_MEM_GUEST_MEMFD is not writable
from userspace, so there would be no way to write to a read-only
guest_memfd).
- Update documentation for KVM_SW_PROTECTED_VM to make it abundantly
clear that such VMs are purely for development and testing.
- Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term plan
is to support confidential VMs with deterministic private memory (SNP
and TDX) only in the TDP MMU.
- Fix a bug in a GUEST_MEMFD dirty logging test that caused false passes.
x86 fixes:
- Fix missing marking of a guest page as dirty when emulating an atomic access.
- Check for mmu_notifier invalidation events before faulting in the pfn,
and before acquiring mmu_lock, to avoid unnecessary work and lock
contention with preemptible kernels (including CONFIG_PREEMPT_DYNAMIC
in non-preemptible mode).
- Disable AMD DebugSwap by default, it breaks VMSA signing and will be
re-enabled with a better VM creation API in 6.10.
- Do the cache flush of converted pages in svm_register_enc_region() before
dropping kvm->lock, to avoid a race with unregistering of the same region
and the consequent use-after-free issue.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"KVM GUEST_MEMFD fixes for 6.8:
- Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY
to avoid creating an inconsistent ABI (KVM_MEM_GUEST_MEMFD is not
writable from userspace, so there would be no way to write to a
read-only guest_memfd).
- Update documentation for KVM_SW_PROTECTED_VM to make it abundantly
clear that such VMs are purely for development and testing.
- Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term
plan is to support confidential VMs with deterministic private
memory (SNP and TDX) only in the TDP MMU.
- Fix a bug in a GUEST_MEMFD dirty logging test that caused false
passes.
x86 fixes:
- Fix missing marking of a guest page as dirty when emulating an
atomic access.
- Check for mmu_notifier invalidation events before faulting in the
pfn, and before acquiring mmu_lock, to avoid unnecessary work and
lock contention with preemptible kernels (including
CONFIG_PREEMPT_DYNAMIC in non-preemptible mode).
- Disable AMD DebugSwap by default, it breaks VMSA signing and will
be re-enabled with a better VM creation API in 6.10.
- Do the cache flush of converted pages in svm_register_enc_region()
before dropping kvm->lock, to avoid a race with unregistering of
the same region and the consequent use-after-free issue"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
SEV: disable SEV-ES DebugSwap by default
KVM: x86/mmu: Retry fault before acquiring mmu_lock if mapping is changing
KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region()
KVM: selftests: Add a testcase to verify GUEST_MEMFD and READONLY are exclusive
KVM: selftests: Create GUEST_MEMFD for relevant invalid flags testcases
KVM: x86/mmu: Restrict KVM_SW_PROTECTED_VM to the TDP MMU
KVM: x86: Update KVM_SW_PROTECTED_VM docs to make it clear they're a WIP
KVM: Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY
KVM: x86: Mark target gfn of emulated atomic instruction as dirty
The DebugSwap feature of SEV-ES provides a way for confidential guests to use
data breakpoints. However, because the status of the DebugSwap feature is
recorded in the VMSA, enabling it by default invalidates the attestation
signatures. In 6.10 we will introduce a new API to create SEV VMs that
will allow enabling DebugSwap based on what the user tells KVM to do.
Contextually, we will change the legacy KVM_SEV_ES_INIT API to never
enable DebugSwap.
For compatibility with kernels that pre-date the introduction of DebugSwap,
as well as with those where KVM_SEV_ES_INIT will never enable it, do not enable
the feature by default. If anybody wants to use it, for now they can enable
the sev_es_debug_swap_enabled module parameter, but this will result in a
warning.
Fixes: d1f85fbe83 ("KVM: SEV: Enable data breakpoints in SEV-ES")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM GUEST_MEMFD fixes for 6.8:
- Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY to
avoid creating ABI that KVM can't sanely support.
- Update documentation for KVM_SW_PROTECTED_VM to make it abundantly
clear that such VMs are purely a development and testing vehicle, and
come with zero guarantees.
- Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term plan
is to support confidential VMs with deterministic private memory (SNP
and TDX) only in the TDP MMU.
- Fix a bug in a GUEST_MEMFD negative test that resulted in false passes
when verifying that KVM_MEM_GUEST_MEMFD memslots can't be dirty logged.
KVM x86 fixes for 6.8, round 2:
- When emulating an atomic access, mark the gfn as dirty in the memslot
to fix a bug where KVM could fail to mark the slot as dirty during live
migration, ultimately resulting in guest data corruption due to a dirty
page not being re-copied from the source to the target.
- Check for mmu_notifier invalidation events before faulting in the pfn,
and before acquiring mmu_lock, to avoid unnecessary work and lock
contention. Contending mmu_lock is especially problematic on preemptible
kernels, as KVM may yield mmu_lock in response to the contention, which
severely degrades overall performance due to vCPUs making it difficult
for the task that triggered invalidation to make forward progress.
Note, due to another kernel bug, this fix isn't limited to preemtible
kernels, as any kernel built with CONFIG_PREEMPT_DYNAMIC=y will yield
contended rwlocks and spinlocks.
https://lore.kernel.org/all/20240110214723.695930-1-seanjc@google.com
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Merge tag 'hyperv-fixes-signed-20240303' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Multiple fixes, cleanups and documentations for Hyper-V core code and
drivers
* tag 'hyperv-fixes-signed-20240303' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
Drivers: hv: vmbus: make hv_bus const
x86/hyperv: Allow 15-bit APIC IDs for VTL platforms
x86/hyperv: Make encrypted/decrypted changes safe for load_unaligned_zeropad()
x86/mm: Regularize set_memory_p() parameters and make non-static
x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback
Documentation: hyperv: Add overview of PCI pass-thru device support
Drivers: hv: vmbus: Update indentation in create_gpadl_header()
Drivers: hv: vmbus: Remove duplication and cleanup code in create_gpadl_header()
fbdev/hyperv_fb: Fix logic error for Gen2 VMs in hvfb_getmem()
Drivers: hv: vmbus: Calculate ring buffer size for more efficient use of memory
hv_utils: Allow implicit ICTIMESYNCFLAG_SYNC
be used by kexec only
- Make sure MKTME feature detection happens at an earlier time in the
boot process so that the physical address size supported by the CPU is
properly corrected and MTRR masks are programmed properly, leading to
TDX systems booting without disable_mtrr_cleanup on the cmdline
- Make sure the different address sizes supported by the CPU are read
out as early as possible
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Merge tag 'x86_urgent_for_v6.8_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Do not reserve SETUP_RNG_SEED setup data in the e820 map as it should
be used by kexec only
- Make sure MKTME feature detection happens at an earlier time in the
boot process so that the physical address size supported by the CPU
is properly corrected and MTRR masks are programmed properly, leading
to TDX systems booting without disable_mtrr_cleanup on the cmdline
- Make sure the different address sizes supported by the CPU are read
out as early as possible
* tag 'x86_urgent_for_v6.8_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/e820: Don't reserve SETUP_RNG_SEED in e820
x86/cpu/intel: Detect TME keyid bits before setting MTRR mask registers
x86/cpu: Allow reducing x86_phys_bits during early_identify_cpu()
SETUP_RNG_SEED in setup_data is supplied by kexec and should
not be reserved in the e820 map.
Doing so reserves 16 bytes of RAM when booting with kexec.
(16 bytes because data->len is zeroed by parse_setup_data so only
sizeof(setup_data) is reserved.)
When kexec is used repeatedly, each boot adds two entries in the
kexec-provided e820 map as the 16-byte range splits a larger
range of usable memory. Eventually all of the 128 available entries
get used up. The next split will result in losing usable memory
as the new entries cannot be added to the e820 map.
Fixes: 68b8e9713c ("x86/setup: Use rng seeds from setup_data")
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/ZbmOjKnARGiaYBd5@dwarf.suse.cz
The current method for signaling the compatibility of a Hyper-V host
with MSIs featuring 15-bit APIC IDs relies on a synthetic cpuid leaf.
However, for higher VTLs, this leaf is not reported, due to the absence
of an IO-APIC.
As an alternative, assume that when running at a high VTL, the host
supports 15-bit APIC IDs. This assumption is safe, as Hyper-V does not
employ any architectural MSIs at higher VTLs
This unblocks startup of VTL2 environments with more than 256 CPUs.
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1705341460-18394-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1705341460-18394-1-git-send-email-ssengar@linux.microsoft.com>
In a CoCo VM, when transitioning memory from encrypted to decrypted, or
vice versa, the caller of set_memory_encrypted() or set_memory_decrypted()
is responsible for ensuring the memory isn't in use and isn't referenced
while the transition is in progress. The transition has multiple steps,
and the memory is in an inconsistent state until all steps are complete.
A reference while the state is inconsistent could result in an exception
that can't be cleanly fixed up.
However, the kernel load_unaligned_zeropad() mechanism could cause a stray
reference that can't be prevented by the caller of set_memory_encrypted()
or set_memory_decrypted(), so there's specific code to handle this case.
But a CoCo VM running on Hyper-V may be configured to run with a paravisor,
with the #VC or #VE exception routed to the paravisor. There's no
architectural way to forward the exceptions back to the guest kernel, and
in such a case, the load_unaligned_zeropad() specific code doesn't work.
To avoid this problem, mark pages as "not present" while a transition
is in progress. If load_unaligned_zeropad() causes a stray reference, a
normal page fault is generated instead of #VC or #VE, and the
page-fault-based fixup handlers for load_unaligned_zeropad() resolve the
reference. When the encrypted/decrypted transition is complete, mark the
pages as "present" again.
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/r/20240116022008.1023398-4-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240116022008.1023398-4-mhklinux@outlook.com>
set_memory_p() is currently static. It has parameters that don't
match set_memory_p() under arch/powerpc and that aren't congruent
with the other set_memory_* functions. There's no good reason for
the difference.
Fix this by making the parameters consistent, and update the one
existing call site. Make the function non-static and add it to
include/asm/set_memory.h so that it is completely parallel to
set_memory_np() and is usable in other modules.
No functional change.
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/20240116022008.1023398-3-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240116022008.1023398-3-mhklinux@outlook.com>
In preparation for temporarily marking pages not present during a
transition between encrypted and decrypted, use slow_virt_to_phys()
in the hypervisor callback. As long as the PFN is correct,
slow_virt_to_phys() works even if the leaf PTE is not present.
The existing functions that depend on vmalloc_to_page() all
require that the leaf PTE be marked present, so they don't work.
Update the comments for slow_virt_to_phys() to note this broader usage
and the requirement to work even if the PTE is not marked present.
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Link: https://lore.kernel.org/r/20240116022008.1023398-2-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240116022008.1023398-2-mhklinux@outlook.com>
MKTME repurposes the high bit of physical address to key id for encryption
key and, even though MAXPHYADDR in CPUID[0x80000008] remains the same,
the valid bits in the MTRR mask register are based on the reduced number
of physical address bits.
detect_tme() in arch/x86/kernel/cpu/intel.c detects TME and subtracts
it from the total usable physical bits, but it is called too late.
Move the call to early_init_intel() so that it is called in setup_arch(),
before MTRRs are setup.
This fixes boot on TDX-enabled systems, which until now only worked with
"disable_mtrr_cleanup". Without the patch, the values written to the
MTRRs mask registers were 52-bit wide (e.g. 0x000fffff_80000800) and
the writes failed; with the patch, the values are 46-bit wide, which
matches the reduced MAXPHYADDR that is shown in /proc/cpuinfo.
Reported-by: Zixi Chen <zixchen@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240131230902.1867092-3-pbonzini%40redhat.com
In commit fbf6449f84 ("x86/sev-es: Set x86_virt_bits to the correct
value straight away, instead of a two-phase approach"), the initialization
of c->x86_phys_bits was moved after this_cpu->c_early_init(c). This is
incorrect because early_init_amd() expected to be able to reduce the
value according to the contents of CPUID leaf 0x8000001f.
Fortunately, the bug was negated by init_amd()'s call to early_init_amd(),
which does reduce x86_phys_bits in the end. However, this is very
late in the boot process and, most notably, the wrong value is used for
x86_phys_bits when setting up MTRRs.
To fix this, call get_cpu_address_sizes() as soon as X86_FEATURE_CPUID is
set/cleared, and c->extended_cpuid_level is retrieved.
Fixes: fbf6449f84 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240131230902.1867092-2-pbonzini%40redhat.com
point in the return-to-userspace path, otherwise memory accesses after
the VERW execution could cause data to land in CPU buffers again
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Merge tag 'x86_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Make sure clearing CPU buffers using VERW happens at the latest
possible point in the return-to-userspace path, otherwise memory
accesses after the VERW execution could cause data to land in CPU
buffers again
* tag 'x86_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM/VMX: Move VERW closer to VMentry for MDS mitigation
KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH
x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key
x86/entry_32: Add VERW just before userspace transition
x86/entry_64: Add VERW just before userspace transition
x86/bugs: Add asm helpers for executing VERW
- Fix NUMA initialization from ACPI CEDT.CFMWS
- Fix region assembly failures due to async init order
- Fix / simplify export of qos_class information
- Fix cxl_acpi initialization vs single-window-init failures
- Fix handling of repeated 'pci_channel_io_frozen' notifications
- Workaround platforms that violate host-physical-address ==
system-physical address assumptions
- Defer CXL CPER notification handling to v6.9
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Merge tag 'cxl-fixes-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl
Pull cxl fixes from Dan Williams:
"A collection of significant fixes for the CXL subsystem.
The largest change in this set, that bordered on "new development", is
the fix for the fact that the location of the new qos_class attribute
did not match the Documentation. The fix ends up deleting more code
than it added, and it has a new unit test to backstop basic errors in
this interface going forward. So the "red-diff" and unit test saved
the "rip it out and try again" response.
In contrast, the new notification path for firmware reported CXL
errors (CXL CPER notifications) has a locking context bug that can not
be fixed with a red-diff. Given where the release cycle stands, it is
not comfortable to squeeze in that fix in these waning days. So, that
receives the "back it out and try again later" treatment.
There is a regression fix in the code that establishes memory NUMA
nodes for platform CXL regions. That has an ack from x86 folks. There
are a couple more fixups for Linux to understand (reassemble) CXL
regions instantiated by platform firmware. The policy around platforms
that do not match host-physical-address with system-physical-address
(i.e. systems that have an address translation mechanism between the
address range reported in the ACPI CEDT.CFMWS and endpoint decoders)
has been softened to abort driver load rather than teardown the memory
range (can cause system hangs). Lastly, there is a robustness /
regression fix for cases where the driver would previously continue in
the face of error, and a fixup for PCI error notification handling.
Summary:
- Fix NUMA initialization from ACPI CEDT.CFMWS
- Fix region assembly failures due to async init order
- Fix / simplify export of qos_class information
- Fix cxl_acpi initialization vs single-window-init failures
- Fix handling of repeated 'pci_channel_io_frozen' notifications
- Workaround platforms that violate host-physical-address ==
system-physical address assumptions
- Defer CXL CPER notification handling to v6.9"
* tag 'cxl-fixes-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
cxl/acpi: Fix load failures due to single window creation failure
acpi/ghes: Remove CXL CPER notifications
cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window
cxl/test: Add support for qos_class checking
cxl: Fix sysfs export of qos_class for memdev
cxl: Remove unnecessary type cast in cxl_qos_class_verify()
cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'
cxl/region: Allow out of order assembly of autodiscovered regions
cxl/region: Handle endpoint decoders in cxl_region_find_decoder()
x86/numa: Fix the sort compare func used in numa_fill_memblks()
x86/numa: Fix the address overlap check in numa_fill_memblks()
cxl/pci: Skip to handle RAS errors if CXL.mem device is detached
Retry page faults without acquiring mmu_lock, and without even faulting
the page into the primary MMU, if the resolved gfn is covered by an active
invalidation. Contending for mmu_lock is especially problematic on
preemptible kernels as the mmu_notifier invalidation task will yield
mmu_lock (see rwlock_needbreak()), delay the in-progress invalidation, and
ultimately increase the latency of resolving the page fault. And in the
worst case scenario, yielding will be accompanied by a remote TLB flush,
e.g. if the invalidation covers a large range of memory and vCPUs are
accessing addresses that were already zapped.
Faulting the page into the primary MMU is similarly problematic, as doing
so may acquire locks that need to be taken for the invalidation to
complete (the primary MMU has finer grained locks than KVM's MMU), and/or
may cause unnecessary churn (getting/putting pages, marking them accessed,
etc).
Alternatively, the yielding issue could be mitigated by teaching KVM's MMU
iterators to perform more work before yielding, but that wouldn't solve
the lock contention and would negatively affect scenarios where a vCPU is
trying to fault in an address that is NOT covered by the in-progress
invalidation.
Add a dedicated lockess version of the range-based retry check to avoid
false positives on the sanity check on start+end WARN, and so that it's
super obvious that checking for a racing invalidation without holding
mmu_lock is unsafe (though obviously useful).
Wrap mmu_invalidate_in_progress in READ_ONCE() to ensure that pre-checking
invalidation in a loop won't put KVM into an infinite loop, e.g. due to
caching the in-progress flag and never seeing it go to '0'.
Force a load of mmu_invalidate_seq as well, even though it isn't strictly
necessary to avoid an infinite loop, as doing so improves the probability
that KVM will detect an invalidation that already completed before
acquiring mmu_lock and bailing anyways.
Do the pre-check even for non-preemptible kernels, as waiting to detect
the invalidation until mmu_lock is held guarantees the vCPU will observe
the worst case latency in terms of handling the fault, and can generate
even more mmu_lock contention. E.g. the vCPU will acquire mmu_lock,
detect retry, drop mmu_lock, re-enter the guest, retake the fault, and
eventually re-acquire mmu_lock. This behavior is also why there are no
new starvation issues due to losing the fairness guarantees provided by
rwlocks: if the vCPU needs to retry, it _must_ drop mmu_lock, i.e. waiting
on mmu_lock doesn't guarantee forward progress in the face of _another_
mmu_notifier invalidation event.
Note, adding READ_ONCE() isn't entirely free, e.g. on x86, the READ_ONCE()
may generate a load into a register instead of doing a direct comparison
(MOV+TEST+Jcc instead of CMP+Jcc), but practically speaking the added cost
is a few bytes of code and maaaaybe a cycle or three.
Reported-by: Yan Zhao <yan.y.zhao@intel.com>
Closes: https://lore.kernel.org/all/ZNnPF4W26ZbAyGto@yzhao56-desk.sh.intel.com
Reported-by: Friedrich Weber <f.weber@proxmox.com>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Cc: Yuan Yao <yuan.yao@linux.intel.com>
Cc: Xu Yilun <yilun.xu@linux.intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20240222012640.2820927-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Do the cache flush of converted pages in svm_register_enc_region() before
dropping kvm->lock to fix use-after-free issues where region and/or its
array of pages could be freed by a different task, e.g. if userspace has
__unregister_enc_region_locked() already queued up for the region.
Note, the "obvious" alternative of using local variables doesn't fully
resolve the bug, as region->pages is also dynamically allocated. I.e. the
region structure itself would be fine, but region->pages could be freed.
Flushing multiple pages under kvm->lock is unfortunate, but the entire
flow is a rare slow path, and the manual flush is only needed on CPUs that
lack coherency for encrypted memory.
Fixes: 19a23da539 ("Fix unsynchronized access to sev members through svm_register_enc_region")
Reported-by: Gabe Kirkpatrick <gkirkpatrick@google.com>
Cc: Josh Eads <josheads@google.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20240217013430.2079561-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Advertise and support software-protected VMs if and only if the TDP MMU is
enabled, i.e. disallow KVM_SW_PROTECTED_VM if TDP is enabled for KVM's
legacy/shadow MMU. TDP support for the shadow MMU is maintenance-only,
e.g. support for TDX and SNP will also be restricted to the TDP MMU.
Fixes: 89ea60c2c7 ("KVM: x86: Add support for "protected VMs" that can utilize private memory")
Link: https://lore.kernel.org/r/20240222190612.2942589-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Rewrite the help message for KVM_SW_PROTECTED_VM to make it clear that
software-protected VMs are a development and testing vehicle for
guest_memfd(), and that attempting to use KVM_SW_PROTECTED_VM for anything
remotely resembling a "real" VM will fail. E.g. any memory accesses from
KVM will incorrectly access shared memory, nested TDP is wildly broken,
and so on and so forth.
Update KVM's API documentation with similar warnings to discourage anyone
from attempting to run anything but selftests with KVM_X86_SW_PROTECTED_VM.
Fixes: 89ea60c2c7 ("KVM: x86: Add support for "protected VMs" that can utilize private memory")
Link: https://lore.kernel.org/r/20240222190612.2942589-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Current release - regressions:
- af_unix: fix another unix GC hangup
Previous releases - regressions:
- core: fix a possible AF_UNIX deadlock
- bpf: fix NULL pointer dereference in sk_psock_verdict_data_ready()
- netfilter: nft_flow_offload: release dst in case direct xmit path is used
- bridge: switchdev: ensure MDB events are delivered exactly once
- l2tp: pass correct message length to ip6_append_data
- dccp/tcp: unhash sk from ehash for tb2 alloc failure after check_estalblished()
- tls: fixes for record type handling with PEEK
- devlink: fix possible use-after-free and memory leaks in devlink_init()
Previous releases - always broken:
- bpf: fix an oops when attempting to read the vsyscall
page through bpf_probe_read_kernel
- sched: act_mirred: use the backlog for mirred ingress
- netfilter: nft_flow_offload: fix dst refcount underflow
- ipv6: sr: fix possible use-after-free and null-ptr-deref
- mptcp: fix several data races
- phonet: take correct lock to peek at the RX queue
Misc:
- handful of fixes and reliability improvements for selftests
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-6.8.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from bpf and netfilter.
Current release - regressions:
- af_unix: fix another unix GC hangup
Previous releases - regressions:
- core: fix a possible AF_UNIX deadlock
- bpf: fix NULL pointer dereference in sk_psock_verdict_data_ready()
- netfilter: nft_flow_offload: release dst in case direct xmit path
is used
- bridge: switchdev: ensure MDB events are delivered exactly once
- l2tp: pass correct message length to ip6_append_data
- dccp/tcp: unhash sk from ehash for tb2 alloc failure after
check_estalblished()
- tls: fixes for record type handling with PEEK
- devlink: fix possible use-after-free and memory leaks in
devlink_init()
Previous releases - always broken:
- bpf: fix an oops when attempting to read the vsyscall page through
bpf_probe_read_kernel
- sched: act_mirred: use the backlog for mirred ingress
- netfilter: nft_flow_offload: fix dst refcount underflow
- ipv6: sr: fix possible use-after-free and null-ptr-deref
- mptcp: fix several data races
- phonet: take correct lock to peek at the RX queue
Misc:
- handful of fixes and reliability improvements for selftests"
* tag 'net-6.8.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (72 commits)
l2tp: pass correct message length to ip6_append_data
net: phy: realtek: Fix rtl8211f_config_init() for RTL8211F(D)(I)-VD-CG PHY
selftests: ioam: refactoring to align with the fix
Fix write to cloned skb in ipv6_hop_ioam()
phonet/pep: fix racy skb_queue_empty() use
phonet: take correct lock to peek at the RX queue
net: sparx5: Add spinlock for frame transmission from CPU
net/sched: flower: Add lock protection when remove filter handle
devlink: fix port dump cmd type
net: stmmac: Fix EST offset for dwmac 5.10
tools: ynl: don't leak mcast_groups on init error
tools: ynl: make sure we always pass yarg to mnl_cb_run
net: mctp: put sock on tag allocation failure
netfilter: nf_tables: use kzalloc for hook allocation
netfilter: nf_tables: register hooks last when adding new chain/flowtable
netfilter: nft_flow_offload: release dst in case direct xmit path is used
netfilter: nft_flow_offload: reset dst in route object after setting up flow
netfilter: nf_tables: set dormant flag on hook register failure
selftests: tls: add test for peeking past a record of a different type
selftests: tls: add test for merging of same-type control messages
...
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2024-02-22
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 24 day(s) which contain
a total of 15 files changed, 217 insertions(+), 17 deletions(-).
The main changes are:
1) Fix a syzkaller-triggered oops when attempting to read the vsyscall
page through bpf_probe_read_kernel and friends, from Hou Tao.
2) Fix a kernel panic due to uninitialized iter position pointer in
bpf_iter_task, from Yafang Shao.
3) Fix a race between bpf_timer_cancel_and_free and bpf_timer_cancel,
from Martin KaFai Lau.
4) Fix a xsk warning in skb_add_rx_frag() (under CONFIG_DEBUG_NET)
due to incorrect truesize accounting, from Sebastian Andrzej Siewior.
5) Fix a NULL pointer dereference in sk_psock_verdict_data_ready,
from Shigeru Yoshida.
6) Fix a resolve_btfids warning when bpf_cpumask symbol cannot be
resolved, from Hari Bathini.
bpf-for-netdev
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready()
selftests/bpf: Add negtive test cases for task iter
bpf: Fix an issue due to uninitialized bpf_iter_task
selftests/bpf: Test racing between bpf_timer_cancel_and_free and bpf_timer_cancel
bpf: Fix racing between bpf_timer_cancel_and_free and bpf_timer_cancel
selftest/bpf: Test the read of vsyscall page under x86-64
x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()
x86/mm: Move is_vsyscall_vaddr() into asm/vsyscall.h
bpf, scripts: Correct GPL license name
xsk: Add truesize to skb_add_rx_frag().
bpf: Fix warning for bpf_cpumask in verifier
====================
Link: https://lore.kernel.org/r/20240221231826.1404-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
During VMentry VERW is executed to mitigate MDS. After VERW, any memory
access like register push onto stack may put host data in MDS affected
CPU buffers. A guest can then use MDS to sample host data.
Although likelihood of secrets surviving in registers at current VERW
callsite is less, but it can't be ruled out. Harden the MDS mitigation
by moving the VERW mitigation late in VMentry path.
Note that VERW for MMIO Stale Data mitigation is unchanged because of
the complexity of per-guest conditional VERW which is not easy to handle
that late in asm with no GPRs available. If the CPU is also affected by
MDS, VERW is unconditionally executed late in asm regardless of guest
having MMIO access.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-6-a6216d83edb7%40linux.intel.com
Use EFLAGS.CF instead of EFLAGS.ZF to track whether to use VMRESUME versus
VMLAUNCH. Freeing up EFLAGS.ZF will allow doing VERW, which clobbers ZF,
for MDS mitigations as late as possible without needing to duplicate VERW
for both paths.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-5-a6216d83edb7%40linux.intel.com
The VERW mitigation at exit-to-user is enabled via a static branch
mds_user_clear. This static branch is never toggled after boot, and can
be safely replaced with an ALTERNATIVE() which is convenient to use in
asm.
Switch to ALTERNATIVE() to use the VERW mitigation late in exit-to-user
path. Also remove the now redundant VERW in exc_nmi() and
arch_exit_to_user_mode().
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-4-a6216d83edb7%40linux.intel.com
Mitigation for MDS is to use VERW instruction to clear any secrets in
CPU Buffers. Any memory accesses after VERW execution can still remain
in CPU buffers. It is safer to execute VERW late in return to user path
to minimize the window in which kernel data can end up in CPU buffers.
There are not many kernel secrets to be had after SWITCH_TO_USER_CR3.
Add support for deploying VERW mitigation after user register state is
restored. This helps minimize the chances of kernel data ending up into
CPU buffers after executing VERW.
Note that the mitigation at the new location is not yet enabled.
Corner case not handled
=======================
Interrupts returning to kernel don't clear CPUs buffers since the
exit-to-user path is expected to do that anyways. But, there could be
a case when an NMI is generated in kernel after the exit-to-user path
has cleared the buffers. This case is not handled and NMI returning to
kernel don't clear CPU buffers because:
1. It is rare to get an NMI after VERW, but before returning to userspace.
2. For an unprivileged user, there is no known way to make that NMI
less rare or target it.
3. It would take a large number of these precisely-timed NMIs to mount
an actual attack. There's presumably not enough bandwidth.
4. The NMI in question occurs after a VERW, i.e. when user state is
restored and most interesting data is already scrubbed. Whats left
is only the data that NMI touches, and that may or may not be of
any interest.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-2-a6216d83edb7%40linux.intel.com
MDS mitigation requires clearing the CPU buffers before returning to
user. This needs to be done late in the exit-to-user path. Current
location of VERW leaves a possibility of kernel data ending up in CPU
buffers for memory accesses done after VERW such as:
1. Kernel data accessed by an NMI between VERW and return-to-user can
remain in CPU buffers since NMI returning to kernel does not
execute VERW to clear CPU buffers.
2. Alyssa reported that after VERW is executed,
CONFIG_GCC_PLUGIN_STACKLEAK=y scrubs the stack used by a system
call. Memory accesses during stack scrubbing can move kernel stack
contents into CPU buffers.
3. When caller saved registers are restored after a return from
function executing VERW, the kernel stack accesses can remain in
CPU buffers(since they occur after VERW).
To fix this VERW needs to be moved very late in exit-to-user path.
In preparation for moving VERW to entry/exit asm code, create macros
that can be used in asm. Also make VERW patching depend on a new feature
flag X86_FEATURE_CLEAR_CPU_BUF.
Reported-by: Alyssa Milburn <alyssa.milburn@intel.com>
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-1-a6216d83edb7%40linux.intel.com
- Reformat nested if-conditionals in Makefiles with 4 spaces
- Fix CONFIG_DEBUG_INFO_BTF builds for big endian
- Fix modpost for module srcversion
- Fix an escape sequence warning in gen_compile_commands.py
- Fix kallsyms to ignore ARMv4 thunk symbols
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Merge tag 'kbuild-fixes-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- Reformat nested if-conditionals in Makefiles with 4 spaces
- Fix CONFIG_DEBUG_INFO_BTF builds for big endian
- Fix modpost for module srcversion
- Fix an escape sequence warning in gen_compile_commands.py
- Fix kallsyms to ignore ARMv4 thunk symbols
* tag 'kbuild-fixes-v6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kallsyms: ignore ARMv4 thunks along with others
modpost: trim leading spaces when processing source files list
gen_compile_commands: fix invalid escape sequence warning
kbuild: Fix changing ELF file type for output of gen_btf for big endian
docs: kconfig: Fix grammar and formatting
kbuild: use 4-space indentation when followed by conditionals
requested so that mapping of reserved regions is prevented which would
otherwise lead to system crashes on UV machines
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Merge tag 'x86_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
- Use a GB page for identity mapping only when memory of this size is
requested so that mapping of reserved regions is prevented which
would otherwise lead to system crashes on UV machines
* tag 'x86_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
The compare function used to sort memblks into starting address
order fails when the result of its u64 address subtraction gets
truncated to an int upon return.
The impact of the bad sort is that memblks will be filled out
incorrectly. Depending on the set of memblks, a user may see no
errors at all but still have a bad fill, or see messages reporting
a node overlap that leads to numa init failure:
[] node 0 [mem: ] overlaps with node 1 [mem: ]
[] No NUMA configuration found
Replace with a comparison that can only result in: 1, 0, -1.
Fixes: 8f012db27c ("x86/numa: Introduce numa_fill_memblks()")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/99dcb3ae87e04995e9f293f6158dc8fa0749a487.1705085543.git.alison.schofield@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
numa_fill_memblks() fills in the gaps in numa_meminfo memblks over a
physical address range. To do so, it first creates a list of existing
memblks that overlap that address range. The issue is that it is off
by one when comparing to the end of the address range, so memblks
that do not overlap are selected.
The impact of selecting a memblk that does not actually overlap is
that an existing memblk may be filled when the expected action is to
do nothing and return NUMA_NO_MEMBLK to the caller. The caller can
then add a new NUMA node and memblk.
Replace the broken open-coded search for address overlap with the
memblock helper memblock_addrs_overlap(). Update the kernel doc
and in code comments.
Suggested by: "Huang, Ying" <ying.huang@intel.com>
Fixes: 8f012db27c ("x86/numa: Introduce numa_fill_memblks()")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/10a3e6109c34c21a8dd4c513cf63df63481a2b07.1705085543.git.alison.schofield@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When emulating an atomic access on behalf of the guest, mark the target
gfn dirty if the CMPXCHG by KVM is attempted and doesn't fault. This
fixes a bug where KVM effectively corrupts guest memory during live
migration by writing to guest memory without informing userspace that the
page is dirty.
Marking the page dirty got unintentionally dropped when KVM's emulated
CMPXCHG was converted to do a user access. Before that, KVM explicitly
mapped the guest page into kernel memory, and marked the page dirty during
the unmap phase.
Mark the page dirty even if the CMPXCHG fails, as the old data is written
back on failure, i.e. the page is still written. The value written is
guaranteed to be the same because the operation is atomic, but KVM's ABI
is that all writes are dirty logged regardless of the value written. And
more importantly, that's what KVM did before the buggy commit.
Huge kudos to the folks on the Cc list (and many others), who did all the
actual work of triaging and debugging.
Fixes: 1c2361f667 ("KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Cc: Pasha Tatashin <tatashin@google.com>
Cc: Michael Krebs <mkrebs@google.com>
base-commit: 6769ea8da8a93ed4630f1ce64df6aafcaabfce64
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20240215010004.1456078-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
* Avoid dropping the page refcount twice when freeing an unlinked
page-table subtree.
* Don't source the VFIO Kconfig twice
* Fix protected-mode locking order between kvm and vcpus
RISC-V:
* Fix steal-time related sparse warnings
x86:
* Cleanup gtod_is_based_on_tsc() to return "bool" instead of an "int"
* Make a KVM_REQ_NMI request while handling KVM_SET_VCPU_EVENTS if and only
if the incoming events->nmi.pending is non-zero. If the target vCPU is in
the UNITIALIZED state, the spurious request will result in KVM exiting to
userspace, which in turn causes QEMU to constantly acquire and release
QEMU's global mutex, to the point where the BSP is unable to make forward
progress.
* Fix a type (u8 versus u64) goof that results in pmu->fixed_ctr_ctrl being
incorrectly truncated, and ultimately causes KVM to think a fixed counter
has already been disabled (KVM thinks the old value is '0').
* Fix a stack leak in KVM_GET_MSRS where a failed MSR read from userspace
that is ultimately ignored due to ignore_msrs=true doesn't zero the output
as intended.
Selftests cleanups and fixes:
* Remove redundant newlines from error messages.
* Delete an unused variable in the AMX test (which causes build failures when
compiling with -Werror).
* Fail instead of skipping tests if open(), e.g. of /dev/kvm, fails with an
error code other than ENOENT (a Hyper-V selftest bug resulted in an EMFILE,
and the test eventually got skipped).
* Fix TSC related bugs in several Hyper-V selftests.
* Fix a bug in the dirty ring logging test where a sem_post() could be left
pending across multiple runs, resulting in incorrect synchronization between
the main thread and the vCPU worker thread.
* Relax the dirty log split test's assertions on 4KiB mappings to fix false
positives due to the number of mappings for memslot 0 (used for code and
data that is NOT being dirty logged) changing, e.g. due to NUMA balancing.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"ARM:
- Avoid dropping the page refcount twice when freeing an unlinked
page-table subtree.
- Don't source the VFIO Kconfig twice
- Fix protected-mode locking order between kvm and vcpus
RISC-V:
- Fix steal-time related sparse warnings
x86:
- Cleanup gtod_is_based_on_tsc() to return "bool" instead of an "int"
- Make a KVM_REQ_NMI request while handling KVM_SET_VCPU_EVENTS if
and only if the incoming events->nmi.pending is non-zero. If the
target vCPU is in the UNITIALIZED state, the spurious request will
result in KVM exiting to userspace, which in turn causes QEMU to
constantly acquire and release QEMU's global mutex, to the point
where the BSP is unable to make forward progress.
- Fix a type (u8 versus u64) goof that results in pmu->fixed_ctr_ctrl
being incorrectly truncated, and ultimately causes KVM to think a
fixed counter has already been disabled (KVM thinks the old value
is '0').
- Fix a stack leak in KVM_GET_MSRS where a failed MSR read from
userspace that is ultimately ignored due to ignore_msrs=true
doesn't zero the output as intended.
Selftests cleanups and fixes:
- Remove redundant newlines from error messages.
- Delete an unused variable in the AMX test (which causes build
failures when compiling with -Werror).
- Fail instead of skipping tests if open(), e.g. of /dev/kvm, fails
with an error code other than ENOENT (a Hyper-V selftest bug
resulted in an EMFILE, and the test eventually got skipped).
- Fix TSC related bugs in several Hyper-V selftests.
- Fix a bug in the dirty ring logging test where a sem_post() could
be left pending across multiple runs, resulting in incorrect
synchronization between the main thread and the vCPU worker thread.
- Relax the dirty log split test's assertions on 4KiB mappings to fix
false positives due to the number of mappings for memslot 0 (used
for code and data that is NOT being dirty logged) changing, e.g.
due to NUMA balancing"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (25 commits)
KVM: arm64: Fix double-free following kvm_pgtable_stage2_free_unlinked()
RISC-V: KVM: Use correct restricted types
RISC-V: paravirt: Use correct restricted types
RISC-V: paravirt: steal_time should be static
KVM: selftests: Don't assert on exact number of 4KiB in dirty log split test
KVM: selftests: Fix a semaphore imbalance in the dirty ring logging test
KVM: x86: Fix KVM_GET_MSRS stack info leak
KVM: arm64: Do not source virt/lib/Kconfig twice
KVM: x86/pmu: Fix type length error when reading pmu->fixed_ctr_ctrl
KVM: x86: Make gtod_is_based_on_tsc() return 'bool'
KVM: selftests: Make hyperv_clock require TSC based system clocksource
KVM: selftests: Run clocksource dependent tests with hyperv_clocksource_tsc_page too
KVM: selftests: Use generic sys_clocksource_is_tsc() in vmx_nested_tsc_scaling_test
KVM: selftests: Generalize check_clocksource() from kvm_clock_test
KVM: x86: make KVM_REQ_NMI request iff NMI pending for vcpu
KVM: arm64: Fix circular locking dependency
KVM: selftests: Fail tests when open() fails with !ENOENT
KVM: selftests: Avoid infinite loop in hyperv_features when invtsc is missing
KVM: selftests: Delete superfluous, unused "stage" variable in AMX test
KVM: selftests: x86_64: Remove redundant newlines
...
When trying to use copy_from_kernel_nofault() to read vsyscall page
through a bpf program, the following oops was reported:
BUG: unable to handle page fault for address: ffffffffff600000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 3231067 P4D 3231067 PUD 3233067 PMD 3235067 PTE 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 20390 Comm: test_progs ...... 6.7.0+ #58
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......
RIP: 0010:copy_from_kernel_nofault+0x6f/0x110
......
Call Trace:
<TASK>
? copy_from_kernel_nofault+0x6f/0x110
bpf_probe_read_kernel+0x1d/0x50
bpf_prog_2061065e56845f08_do_probe_read+0x51/0x8d
trace_call_bpf+0xc5/0x1c0
perf_call_bpf_enter.isra.0+0x69/0xb0
perf_syscall_enter+0x13e/0x200
syscall_trace_enter+0x188/0x1c0
do_syscall_64+0xb5/0xe0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
</TASK>
......
---[ end trace 0000000000000000 ]---
The oops is triggered when:
1) A bpf program uses bpf_probe_read_kernel() to read from the vsyscall
page and invokes copy_from_kernel_nofault() which in turn calls
__get_user_asm().
2) Because the vsyscall page address is not readable from kernel space,
a page fault exception is triggered accordingly.
3) handle_page_fault() considers the vsyscall page address as a user
space address instead of a kernel space address. This results in the
fix-up setup by bpf not being applied and a page_fault_oops() is invoked
due to SMAP.
Considering handle_page_fault() has already considered the vsyscall page
address as a userspace address, fix the problem by disallowing vsyscall
page read for copy_from_kernel_nofault().
Originally-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: syzbot+72aa0161922eba61b50e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/CAG48ez06TZft=ATH1qh2c5mpS5BT8UakwNkzi6nvK5_djC-4Nw@mail.gmail.com
Reported-by: xingwei lee <xrivendell7@gmail.com>
Closes: https://lore.kernel.org/bpf/CABOYnLynjBoFZOf3Z4BhaZkc5hx_kHfsjiW+UWLoB=w33LvScw@mail.gmail.com
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240202103935.3154011-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
