Commit graph

44763 commits

Author SHA1 Message Date
Linus Torvalds
e789286468 Misc fixes:
- Fix an UV boot crash,
 - Skip spurious ENDBR generation on _THIS_IP_,
 - Fix ENDBR use in putuser() asm methods,
 - Fix corner case boot crashes on 5-level paging,
 - and fix a false positive WARNING on LTO kernels.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - Fix an UV boot crash

   - Skip spurious ENDBR generation on _THIS_IP_

   - Fix ENDBR use in putuser() asm methods

   - Fix corner case boot crashes on 5-level paging

   - and fix a false positive WARNING on LTO kernels"

* tag 'x86-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/purgatory: Remove LTO flags
  x86/boot/compressed: Reserve more memory for page tables
  x86/ibt: Avoid duplicate ENDBR in __put_user_nocheck*()
  x86/ibt: Suppress spurious ENDBR
  x86/platform/uv: Use alternate source for socket to node data
2023-09-17 11:13:37 -07:00
Linus Torvalds
e5a710d132 Fix a performance regression on large SMT systems, an Intel SMT4
balancing bug, and a topology setup bug on (Intel) hybrid processors.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Fix a performance regression on large SMT systems, an Intel SMT4
  balancing bug, and a topology setup bug on (Intel) hybrid processors"

* tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sched: Restore the SD_ASYM_PACKING flag in the DIE domain
  sched/fair: Fix SMT4 group_smt_balance handling
  sched/fair: Optimize should_we_balance() for large SMT systems
2023-09-17 11:10:23 -07:00
Song Liu
75b2f7e4c9 x86/purgatory: Remove LTO flags
-flto* implies -ffunction-sections. With LTO enabled, ld.lld generates
multiple .text sections for purgatory.ro:

  $ readelf -S purgatory.ro  | grep " .text"
    [ 1] .text             PROGBITS         0000000000000000  00000040
    [ 7] .text.purgatory   PROGBITS         0000000000000000  000020e0
    [ 9] .text.warn        PROGBITS         0000000000000000  000021c0
    [13] .text.sha256_upda PROGBITS         0000000000000000  000022f0
    [15] .text.sha224_upda PROGBITS         0000000000000000  00002be0
    [17] .text.sha256_fina PROGBITS         0000000000000000  00002bf0
    [19] .text.sha224_fina PROGBITS         0000000000000000  00002cc0

This causes WARNING from kexec_purgatory_setup_sechdrs():

  WARNING: CPU: 26 PID: 110894 at kernel/kexec_file.c:919
  kexec_load_purgatory+0x37f/0x390

Fix this by disabling LTO for purgatory.

[ AFAICT, x86 is the only arch that supports LTO and purgatory. ]

We could also fix this with an explicit linker script to rejoin .text.*
sections back into .text. However, given the benefit of LTOing purgatory
is small, simply disable the production of more .text.* sections for now.

Fixes: b33fff07e3 ("x86, build: allow LTO to be selected")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20230914170138.995606-1-song@kernel.org
2023-09-17 09:49:03 +02:00
Kirill A. Shutemov
f530ee95b7 x86/boot/compressed: Reserve more memory for page tables
The decompressor has a hard limit on the number of page tables it can
allocate. This limit is defined at compile-time and will cause boot
failure if it is reached.

The kernel is very strict and calculates the limit precisely for the
worst-case scenario based on the current configuration. However, it is
easy to forget to adjust the limit when a new use-case arises. The
worst-case scenario is rarely encountered during sanity checks.

In the case of enabling 5-level paging, a use-case was overlooked. The
limit needs to be increased by one to accommodate the additional level.
This oversight went unnoticed until Aaron attempted to run the kernel
via kexec with 5-level paging and unaccepted memory enabled.

Update wost-case calculations to include 5-level paging.

To address this issue, let's allocate some extra space for page tables.
128K should be sufficient for any use-case. The logic can be simplified
by using a single value for all kernel configurations.

[ Also add a warning, should this memory run low - by Dave Hansen. ]

Fixes: 34bbb0009f ("x86/boot/compressed: Enable 5-level paging during decompression stage")
Reported-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230915070221.10266-1-kirill.shutemov@linux.intel.com
2023-09-17 09:48:57 +02:00
Ricardo Neri
108af4b4bd x86/sched: Restore the SD_ASYM_PACKING flag in the DIE domain
Commit 8f2d6c41e5 ("x86/sched: Rewrite topology setup") dropped the
SD_ASYM_PACKING flag in the DIE domain added in commit 044f0e27de
("x86/sched: Add the SD_ASYM_PACKING flag to the die domain of hybrid
processors"). Restore it on hybrid processors.

The die-level domain does not depend on any build configuration and now
x86_sched_itmt_flags() is always needed. Remove the build dependency on
CONFIG_SCHED_[SMT|CLUSTER|MC].

Fixes: 8f2d6c41e5 ("x86/sched: Rewrite topology setup")
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: Caleb Callaway <caleb.callaway@intel.com>
Link: https://lkml.kernel.org/r/20230815035747.11529-1-ricardo.neri-calderon@linux.intel.com
2023-09-13 15:03:18 +02:00
Peter Zijlstra
7575e5a352 x86/ibt: Avoid duplicate ENDBR in __put_user_nocheck*()
Commit cb855971d7 ("x86/putuser: Provide room for padding") changed
__put_user_nocheck_*() into proper functions but failed to note that
SYM_FUNC_START() already provides ENDBR, rendering the explicit ENDBR
superfluous.

Fixes: cb855971d7 ("x86/putuser: Provide room for padding")
Reported-by: David Kaplan <David.Kaplan@amd.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230802110323.086971726@infradead.org
2023-09-12 17:51:24 +02:00
Peter Zijlstra
25e73b7e3f x86/ibt: Suppress spurious ENDBR
It was reported that under certain circumstances GCC emits ENDBR
instructions for _THIS_IP_ usage. Specifically, when it appears at the
start of a basic block -- but not elsewhere.

Since _THIS_IP_ is never used for control flow, these ENDBR
instructions are completely superfluous. Override the _THIS_IP_
definition for x86_64 to avoid this.

Less ENDBR instructions is better.

Fixes: 156ff4a544 ("x86/ibt: Base IBT bits")
Reported-by: David Kaplan <David.Kaplan@amd.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230802110323.016197440@infradead.org
2023-09-12 17:50:53 +02:00
Steve Wahl
5290e88ba2 x86/platform/uv: Use alternate source for socket to node data
The UV code attempts to build a set of tables to allow it to do
bidirectional socket<=>node lookups.

But when nr_cpus is set to a smaller number than actually present, the
cpu_to_node() mapping information for unused CPUs is not available to
build_socket_tables(). This results in skipping some nodes or sockets
when creating the tables and leaving some -1's for later code to trip.
over, causing oopses.

The problem is that the socket<=>node lookups are created by doing a
loop over all CPUs, then looking up the CPU's APICID and socket. But
if a CPU is not present, there is no way to start this lookup.

Instead of looping over all CPUs, take CPUs out of the equation
entirely. Loop over all APICIDs which are mapped to a valid NUMA node.
Then just extract the socket-id from the APICID.

This avoid tripping over disabled CPUs.

Fixes: 8a50c58519 ("x86/platform/uv: UV support for sub-NUMA clustering")
Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230807141730.1117278-1-steve.wahl%40hpe.com
2023-09-11 10:06:22 -07:00
Ard Biesheuvel
aba7e066c7 efi/x86: Ensure that EFI_RUNTIME_MAP is enabled for kexec
CONFIG_EFI_RUNTIME_MAP needs to be enabled in order for kexec to be able
to provide the required information about the EFI runtime mappings to
the incoming kernel, regardless of whether kexec_load() or
kexec_file_load() is being used. Without this information, kexec boot in
EFI mode is not possible.

The CONFIG_EFI_RUNTIME_MAP option is currently directly configurable if
CONFIG_EXPERT is enabled, so that it can be turned on for debugging
purposes even if KEXEC is not enabled. However, the upshot of this is
that it can also be disabled even when it shouldn't.

So tweak the Kconfig declarations to avoid this situation.

Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-11 06:37:50 +00:00
Ard Biesheuvel
762f169f5d efi/x86: Move EFI runtime call setup/teardown helpers out of line
Only the arch_efi_call_virt() macro that some architectures override
needs to be a macro, given that it is variadic and encapsulates calls
via function pointers that have different prototypes.

The associated setup and teardown code are not special in this regard,
and don't need to be instantiated at each call site. So turn them into
ordinary C functions and move them out of line.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-11 06:37:50 +00:00
Linus Torvalds
e56b2b6057 Fix preemption delays in the SGX code, remove unnecessarily UAPI-exported code,
fix a ld.lld linker (in)compatibility quirk and make the x86 SMP init code a bit
 more conservative to fix kexec() lockups.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Fix preemption delays in the SGX code, remove unnecessarily
  UAPI-exported code, fix a ld.lld linker (in)compatibility quirk and
  make the x86 SMP init code a bit more conservative to fix kexec()
  lockups"

* tag 'x86-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sgx: Break up long non-preemptible delays in sgx_vepc_release()
  x86: Remove the arch_calc_vm_prot_bits() macro from the UAPI
  x86/build: Fix linker fill bytes quirk/incompatibility for ld.lld
  x86/smp: Don't send INIT to non-present and non-booted CPUs
2023-09-10 10:39:31 -07:00
Linus Torvalds
e79dbf03d8 Work around a firmware bug in the uncore PMU driver,
affecting certain Intel systems.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 perf event fix from Ingo Molnar:
 "Work around a firmware bug in the uncore PMU driver, affecting certain
  Intel systems"

* tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/uncore: Correct the number of CHAs on EMR
2023-09-10 10:34:46 -07:00
Linus Torvalds
0c02183427 ARM:
* Clean up vCPU targets, always returning generic v8 as the preferred target
 
 * Trap forwarding infrastructure for nested virtualization (used for traps
   that are taken from an L2 guest and are needed by the L1 hypervisor)
 
 * FEAT_TLBIRANGE support to only invalidate specific ranges of addresses
   when collapsing a table PTE to a block PTE.  This avoids that the guest
   refills the TLBs again for addresses that aren't covered by the table PTE.
 
 * Fix vPMU issues related to handling of PMUver.
 
 * Don't unnecessary align non-stack allocations in the EL2 VA space
 
 * Drop HCR_VIRT_EXCP_MASK, which was never used...
 
 * Don't use smp_processor_id() in kvm_arch_vcpu_load(),
   but the cpu parameter instead
 
 * Drop redundant call to kvm_set_pfn_accessed() in user_mem_abort()
 
 * Remove prototypes without implementations
 
 RISC-V:
 
 * Zba, Zbs, Zicntr, Zicsr, Zifencei, and Zihpm support for guest
 
 * Added ONE_REG interface for SATP mode
 
 * Added ONE_REG interface to enable/disable multiple ISA extensions
 
 * Improved error codes returned by ONE_REG interfaces
 
 * Added KVM_GET_REG_LIST ioctl() implementation for KVM RISC-V
 
 * Added get-reg-list selftest for KVM RISC-V
 
 s390:
 
 * PV crypto passthrough enablement (Tony, Steffen, Viktor, Janosch)
   Allows a PV guest to use crypto cards. Card access is governed by
   the firmware and once a crypto queue is "bound" to a PV VM every
   other entity (PV or not) looses access until it is not bound
   anymore. Enablement is done via flags when creating the PV VM.
 
 * Guest debug fixes (Ilya)
 
 x86:
 
 * Clean up KVM's handling of Intel architectural events
 
 * Intel bugfixes
 
 * Add support for SEV-ES DebugSwap, allowing SEV-ES guests to use debug
   registers and generate/handle #DBs
 
 * Clean up LBR virtualization code
 
 * Fix a bug where KVM fails to set the target pCPU during an IRTE update
 
 * Fix fatal bugs in SEV-ES intrahost migration
 
 * Fix a bug where the recent (architecturally correct) change to reinject
   #BP and skip INT3 broke SEV guests (can't decode INT3 to skip it)
 
 * Retry APIC map recalculation if a vCPU is added/enabled
 
 * Overhaul emergency reboot code to bring SVM up to par with VMX, tie the
   "emergency disabling" behavior to KVM actually being loaded, and move all of
   the logic within KVM
 
 * Fix user triggerable WARNs in SVM where KVM incorrectly assumes the TSC
   ratio MSR cannot diverge from the default when TSC scaling is disabled
   up related code
 
 * Add a framework to allow "caching" feature flags so that KVM can check if
   the guest can use a feature without needing to search guest CPUID
 
 * Rip out the ancient MMU_DEBUG crud and replace the useful bits with
   CONFIG_KVM_PROVE_MMU
 
 * Fix KVM's handling of !visible guest roots to avoid premature triple fault
   injection
 
 * Overhaul KVM's page-track APIs, and KVMGT's usage, to reduce the API surface
   that is needed by external users (currently only KVMGT), and fix a variety
   of issues in the process
 
 This last item had a silly one-character bug in the topic branch that
 was sent to me.  Because it caused pretty bad selftest failures in
 some configurations, I decided to squash in the fix.  So, while the
 exact commit ids haven't been in linux-next, the code has (from the
 kvm-x86 tree).
 
 Generic:
 
 * Wrap kvm_{gfn,hva}_range.pte in a union to allow mmu_notifier events to pass
   action specific data without needing to constantly update the main handlers.
 
 * Drop unused function declarations
 
 Selftests:
 
 * Add testcases to x86's sync_regs_test for detecting KVM TOCTOU bugs
 
 * Add support for printf() in guest code and covert all guest asserts to use
   printf-based reporting
 
 * Clean up the PMU event filter test and add new testcases
 
 * Include x86 selftests in the KVM x86 MAINTAINERS entry
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "ARM:

   - Clean up vCPU targets, always returning generic v8 as the preferred
     target

   - Trap forwarding infrastructure for nested virtualization (used for
     traps that are taken from an L2 guest and are needed by the L1
     hypervisor)

   - FEAT_TLBIRANGE support to only invalidate specific ranges of
     addresses when collapsing a table PTE to a block PTE. This avoids
     that the guest refills the TLBs again for addresses that aren't
     covered by the table PTE.

   - Fix vPMU issues related to handling of PMUver.

   - Don't unnecessary align non-stack allocations in the EL2 VA space

   - Drop HCR_VIRT_EXCP_MASK, which was never used...

   - Don't use smp_processor_id() in kvm_arch_vcpu_load(), but the cpu
     parameter instead

   - Drop redundant call to kvm_set_pfn_accessed() in user_mem_abort()

   - Remove prototypes without implementations

  RISC-V:

   - Zba, Zbs, Zicntr, Zicsr, Zifencei, and Zihpm support for guest

   - Added ONE_REG interface for SATP mode

   - Added ONE_REG interface to enable/disable multiple ISA extensions

   - Improved error codes returned by ONE_REG interfaces

   - Added KVM_GET_REG_LIST ioctl() implementation for KVM RISC-V

   - Added get-reg-list selftest for KVM RISC-V

  s390:

   - PV crypto passthrough enablement (Tony, Steffen, Viktor, Janosch)

     Allows a PV guest to use crypto cards. Card access is governed by
     the firmware and once a crypto queue is "bound" to a PV VM every
     other entity (PV or not) looses access until it is not bound
     anymore. Enablement is done via flags when creating the PV VM.

   - Guest debug fixes (Ilya)

  x86:

   - Clean up KVM's handling of Intel architectural events

   - Intel bugfixes

   - Add support for SEV-ES DebugSwap, allowing SEV-ES guests to use
     debug registers and generate/handle #DBs

   - Clean up LBR virtualization code

   - Fix a bug where KVM fails to set the target pCPU during an IRTE
     update

   - Fix fatal bugs in SEV-ES intrahost migration

   - Fix a bug where the recent (architecturally correct) change to
     reinject #BP and skip INT3 broke SEV guests (can't decode INT3 to
     skip it)

   - Retry APIC map recalculation if a vCPU is added/enabled

   - Overhaul emergency reboot code to bring SVM up to par with VMX, tie
     the "emergency disabling" behavior to KVM actually being loaded,
     and move all of the logic within KVM

   - Fix user triggerable WARNs in SVM where KVM incorrectly assumes the
     TSC ratio MSR cannot diverge from the default when TSC scaling is
     disabled up related code

   - Add a framework to allow "caching" feature flags so that KVM can
     check if the guest can use a feature without needing to search
     guest CPUID

   - Rip out the ancient MMU_DEBUG crud and replace the useful bits with
     CONFIG_KVM_PROVE_MMU

   - Fix KVM's handling of !visible guest roots to avoid premature
     triple fault injection

   - Overhaul KVM's page-track APIs, and KVMGT's usage, to reduce the
     API surface that is needed by external users (currently only
     KVMGT), and fix a variety of issues in the process

  Generic:

   - Wrap kvm_{gfn,hva}_range.pte in a union to allow mmu_notifier
     events to pass action specific data without needing to constantly
     update the main handlers.

   - Drop unused function declarations

  Selftests:

   - Add testcases to x86's sync_regs_test for detecting KVM TOCTOU bugs

   - Add support for printf() in guest code and covert all guest asserts
     to use printf-based reporting

   - Clean up the PMU event filter test and add new testcases

   - Include x86 selftests in the KVM x86 MAINTAINERS entry"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (279 commits)
  KVM: x86/mmu: Include mmu.h in spte.h
  KVM: x86/mmu: Use dummy root, backed by zero page, for !visible guest roots
  KVM: x86/mmu: Disallow guest from using !visible slots for page tables
  KVM: x86/mmu: Harden TDP MMU iteration against root w/o shadow page
  KVM: x86/mmu: Harden new PGD against roots without shadow pages
  KVM: x86/mmu: Add helper to convert root hpa to shadow page
  drm/i915/gvt: Drop final dependencies on KVM internal details
  KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers
  KVM: x86/mmu: Drop @slot param from exported/external page-track APIs
  KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled
  KVM: x86/mmu: Assert that correct locks are held for page write-tracking
  KVM: x86/mmu: Rename page-track APIs to reflect the new reality
  KVM: x86/mmu: Drop infrastructure for multiple page-track modes
  KVM: x86/mmu: Use page-track notifiers iff there are external users
  KVM: x86/mmu: Move KVM-only page-track declarations to internal header
  KVM: x86: Remove the unused page-track hook track_flush_slot()
  drm/i915/gvt: switch from ->track_flush_slot() to ->track_remove_region()
  KVM: x86: Add a new page-track hook to handle memslot deletion
  drm/i915/gvt: Don't bother removing write-protection on to-be-deleted slot
  KVM: x86: Reject memslot MOVE operations if KVMGT is attached
  ...
2023-09-07 13:52:20 -07:00
Jack Wang
3d7d72a34e x86/sgx: Break up long non-preemptible delays in sgx_vepc_release()
On large enclaves we hit the softlockup warning with following call trace:

	xa_erase()
	sgx_vepc_release()
	__fput()
	task_work_run()
	do_exit()

The latency issue is similar to the one fixed in:

  8795359e35 ("x86/sgx: Silence softlockup detection when releasing large enclaves")

The test system has 64GB of enclave memory, and all is assigned to a single VM.
Release of 'vepc' takes a longer time and causes long latencies, which triggers
the softlockup warning.

Add cond_resched() to give other tasks a chance to run and reduce
latencies, which also avoids the softlockup detector.

[ mingo: Rewrote the changelog. ]

Fixes: 540745ddbc ("x86/sgx: Introduce virtual EPC for use by KVM guests")
Reported-by: Yu Zhang <yu.zhang@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Yu Zhang <yu.zhang@ionos.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Haitao Huang <haitao.huang@linux.intel.com>
Cc: stable@vger.kernel.org
2023-09-06 23:55:09 +02:00
Thomas Huth
659df86a7b x86: Remove the arch_calc_vm_prot_bits() macro from the UAPI
The arch_calc_vm_prot_bits() macro uses VM_PKEY_BIT0 etc. which are
not part of the UAPI, so the macro is completely useless for userspace.

It is also hidden behind the CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
config switch which we shouldn't expose to userspace. Thus let's move
this macro into a new internal header instead.

Fixes: 8f62c88322 ("x86/mm/pkeys: Add arch-specific VMA protection bits")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Link: https://lore.kernel.org/r/20230906162658.142511-1-thuth@redhat.com
2023-09-06 23:50:46 +02:00
Song Liu
65e710899f x86/build: Fix linker fill bytes quirk/incompatibility for ld.lld
With ":text =0xcccc", ld.lld fills unused text area with 0xcccc0000.
Example objdump -D output:

	ffffffff82b04203:       00 00                   add    %al,(%rax)
	ffffffff82b04205:       cc                      int3
	ffffffff82b04206:       cc                      int3
	ffffffff82b04207:       00 00                   add    %al,(%rax)
	ffffffff82b04209:       cc                      int3
	ffffffff82b0420a:       cc                      int3

Replace it with ":text =0xcccccccc", so we get the following instead:

	ffffffff82b04203:       cc                      int3
	ffffffff82b04204:       cc                      int3
	ffffffff82b04205:       cc                      int3
	ffffffff82b04206:       cc                      int3
	ffffffff82b04207:       cc                      int3
	ffffffff82b04208:       cc                      int3

gcc/ld doesn't seem to have the same issue. The generated code stays the
same for gcc/ld.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Fixes: 7705dc8557 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
Link: https://lore.kernel.org/r/20230906175215.2236033-1-song@kernel.org
2023-09-06 23:49:12 +02:00
Kan Liang
6f7f984fa8 perf/x86/uncore: Correct the number of CHAs on EMR
Starting from SPR, the basic uncore PMON information is retrieved from
the discovery table (resides in an MMIO space populated by BIOS). It is
called the discovery method. The existing value of the type->num_boxes
is from the discovery table.

On some SPR variants, there is a firmware bug that makes the value from the
discovery table incorrect. We use the value from the
SPR_MSR_UNC_CBO_CONFIG MSR to replace the one from the discovery table:

   38776cc45e ("perf/x86/uncore: Correct the number of CHAs on SPR")

Unfortunately, the SPR_MSR_UNC_CBO_CONFIG isn't available for the EMR
XCC (Always returns 0), but the above firmware bug doesn't impact the
EMR XCC.

Don't let the value from the MSR replace the existing value from the
discovery table.

Fixes: 38776cc45e ("perf/x86/uncore: Correct the number of CHAs on SPR")
Reported-by: Stephane Eranian <eranian@google.com>
Reported-by: Yunying Sun <yunying.sun@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Yunying Sun <yunying.sun@intel.com>
Link: https://lore.kernel.org/r/20230905134248.496114-1-kan.liang@linux.intel.com
2023-09-05 21:50:21 +02:00
Linus Torvalds
61401a8724 Kbuild updates for v6.6
- Enable -Wenum-conversion warning option
 
  - Refactor the rpm-pkg target
 
  - Fix scripts/setlocalversion to consider annotated tags for rt-kernel
 
  - Add a jump key feature for the search menu of 'make nconfig'
 
  - Support Qt6 for 'make xconfig'
 
  - Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow, and
    -Wrestrict warnings for W=1 builds
 
  - Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and sparc
 
  - Support DEB_BUILD_OPTIONS=parallel=N for the debian source package
 
  - Refactor scripts/Makefile.modinst and fix some modules_sign issues
 
  - Add a new Kconfig env variable to warn symbols that are not defined anywhere
 
  - Show help messages of config fragments in 'make help'
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Merge tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Enable -Wenum-conversion warning option

 - Refactor the rpm-pkg target

 - Fix scripts/setlocalversion to consider annotated tags for rt-kernel

 - Add a jump key feature for the search menu of 'make nconfig'

 - Support Qt6 for 'make xconfig'

 - Enable -Wformat-overflow, -Wformat-truncation, -Wstringop-overflow,
   and -Wrestrict warnings for W=1 builds

 - Replace <asm/export.h> with <linux/export.h> for alpha, ia64, and
   sparc

 - Support DEB_BUILD_OPTIONS=parallel=N for the debian source package

 - Refactor scripts/Makefile.modinst and fix some modules_sign issues

 - Add a new Kconfig env variable to warn symbols that are not defined
   anywhere

 - Show help messages of config fragments in 'make help'

* tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (62 commits)
  kconfig: fix possible buffer overflow
  kbuild: Show marked Kconfig fragments in "help"
  kconfig: add warn-unknown-symbols sanity check
  kbuild: dummy-tools: make MPROFILE_KERNEL checks work on BE
  Documentation/llvm: refresh docs
  modpost: Skip .llvm.call-graph-profile section check
  kbuild: support modules_sign for external modules as well
  kbuild: support 'make modules_sign' with CONFIG_MODULE_SIG_ALL=n
  kbuild: move more module installation code to scripts/Makefile.modinst
  kbuild: reduce the number of mkdir calls during modules_install
  kbuild: remove $(MODLIB)/source symlink
  kbuild: move depmod rule to scripts/Makefile.modinst
  kbuild: add modules_sign to no-{compiler,sync-config}-targets
  kbuild: do not run depmod for 'make modules_sign'
  kbuild: deb-pkg: support DEB_BUILD_OPTIONS=parallel=N in debian/rules
  alpha: remove <asm/export.h>
  alpha: replace #include <asm/export.h> with #include <linux/export.h>
  ia64: remove <asm/export.h>
  ia64: replace #include <asm/export.h> with #include <linux/export.h>
  sparc: remove <asm/export.h>
  ...
2023-09-05 11:01:47 -07:00
Linus Torvalds
68d76d4e7e This pull request contains the following changes for UML:
- Drop 32-bit checksum implementation and re-use it from arch/x86
 - String function cleanup
 - Fixes for -Wmissing-variable-declarations and -Wmissing-prototypes builds
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Merge tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Drop 32-bit checksum implementation and re-use it from arch/x86

 - String function cleanup

 - Fixes for -Wmissing-variable-declarations and -Wmissing-prototypes
   builds

* tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: virt-pci: fix missing declaration warning
  um: Refactor deprecated strncpy to memcpy
  um: fix 3 instances of -Wmissing-prototypes
  um: port_kern: fix -Wmissing-variable-declarations
  uml: audio: fix -Wmissing-variable-declarations
  um: vector: refactor deprecated strncpy
  um: use obj-y to descend into arch/um/*/
  um: Hard-code the result of 'uname -s'
  um: Use the x86 checksum implementation on 32-bit
  asm-generic: current: Don't include thread-info.h if building asm
  um: Remove unsued extern declaration ldt_host_info()
  um: Fix hostaudio build errors
  um: Remove strlcpy usage
2023-09-04 11:32:21 -07:00
Linus Torvalds
0b90c5637d hyperv-next for v6.6
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Merge tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Support for SEV-SNP guests on Hyper-V (Tianyu Lan)

 - Support for TDX guests on Hyper-V (Dexuan Cui)

 - Use SBRM API in Hyper-V balloon driver (Mitchell Levy)

 - Avoid dereferencing ACPI root object handle in VMBus driver (Maciej
   Szmigiero)

 - A few misecllaneous fixes (Jiapeng Chong, Nathan Chancellor, Saurabh
   Sengar)

* tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits)
  x86/hyperv: Remove duplicate include
  x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's
  x86/hyperv: Remove hv_isolation_type_en_snp
  x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor
  Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor
  x86/hyperv: Introduce a global variable hyperv_paravisor_present
  Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM
  x86/hyperv: Fix serial console interrupts for fully enlightened TDX guests
  Drivers: hv: vmbus: Support fully enlightened TDX guests
  x86/hyperv: Support hypercalls for fully enlightened TDX guests
  x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests
  x86/hyperv: Fix undefined reference to isolation_type_en_snp without CONFIG_HYPERV
  x86/hyperv: Add missing 'inline' to hv_snp_boot_ap() stub
  hv: hyperv.h: Replace one-element array with flexible-array member
  Drivers: hv: vmbus: Don't dereference ACPI root object handle
  x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
  x86/hyperv: Add smp support for SEV-SNP guest
  clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest
  x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest
  drivers: hv: Mark percpu hvcall input arg page unencrypted in SEV-SNP enlightened guest
  ...
2023-09-04 11:26:29 -07:00
Thomas Gleixner
3f874c9b2a x86/smp: Don't send INIT to non-present and non-booted CPUs
Vasant reported that kexec() can hang or reset the machine when it tries to
park CPUs via INIT. This happens when the kernel is using extended APIC,
but the present mask has APIC IDs >= 0x100 enumerated.

As extended APIC can only handle 8 bit of APIC ID sending INIT to APIC ID
0x100 sends INIT to APIC ID 0x0. That's the boot CPU which is special on
x86 and INIT causes the system to hang or resets the machine.

Prevent this by sending INIT only to those CPUs which have been booted
once.

Fixes: 45e34c8af5 ("x86/smp: Put CPUs into INIT on shutdown if possible")
Reported-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/87cyzwjbff.ffs@tglx
2023-09-04 15:41:42 +02:00
Kees Cook
feec5e1f74 kbuild: Show marked Kconfig fragments in "help"
Currently the Kconfig fragments in kernel/configs and arch/*/configs
that aren't used internally aren't discoverable through "make help",
which consists of hard-coded lists of config fragments. Instead, list
all the fragment targets that have a "# Help: " comment prefix so the
targets can be generated dynamically.

Add logic to the Makefile to search for and display the fragment and
comment. Add comments to fragments that are intended to be direct targets.

Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-09-04 02:04:20 +09:00
Linus Torvalds
2fcbb03847 * Mark all Skylake CPUs as vulnerable to GDS
* Fix PKRU covert channel
  * Fix -Wmissing-variable-declarations warning for ia32_xyz_class
  * Fix kernel-doc annotation warning
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Merge tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Dave Hansen:
 "The most important fix here adds a missing CPU model to the recent
  Gather Data Sampling (GDS) mitigation list to ensure that mitigations
  are available on that CPU.

  There are also a pair of warning fixes, and closure of a covert
  channel that pops up when protection keys are disabled.

  Summary:
   - Mark all Skylake CPUs as vulnerable to GDS
   - Fix PKRU covert channel
   - Fix -Wmissing-variable-declarations warning for ia32_xyz_class
   - Fix kernel-doc annotation warning"

* tag 'x86-urgent-2023-09-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/xstate: Fix PKRU covert channel
  x86/irq/i8259: Fix kernel-doc annotation warning
  x86/speculation: Mark all Skylake CPUs as vulnerable to GDS
  x86/audit: Fix -Wmissing-variable-declarations warning for ia32_xyz_class
2023-09-01 16:40:19 -07:00
Linus Torvalds
1c9f8dff62 Char/Misc driver changes for 6.6-rc1
Here is the big set of char/misc and other small driver subsystem
 changes for 6.6-rc1.
 
 Stuff all over the place here, lots of driver updates and changes and
 new additions.  Short summary is:
   - new IIO drivers and updates
   - Interconnect driver updates
   - fpga driver updates and additions
   - fsi driver updates
   - mei driver updates
   - coresight driver updates
   - nvmem driver updates
   - counter driver updates
   - lots of smaller misc and char driver updates and additions
 
 All of these have been in linux-next for a long time with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big set of char/misc and other small driver subsystem
  changes for 6.6-rc1.

  Stuff all over the place here, lots of driver updates and changes and
  new additions. Short summary is:

   - new IIO drivers and updates

   - Interconnect driver updates

   - fpga driver updates and additions

   - fsi driver updates

   - mei driver updates

   - coresight driver updates

   - nvmem driver updates

   - counter driver updates

   - lots of smaller misc and char driver updates and additions

  All of these have been in linux-next for a long time with no reported
  problems"

* tag 'char-misc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (267 commits)
  nvmem: core: Notify when a new layout is registered
  nvmem: core: Do not open-code existing functions
  nvmem: core: Return NULL when no nvmem layout is found
  nvmem: core: Create all cells before adding the nvmem device
  nvmem: u-boot-env:: Replace zero-length array with DECLARE_FLEX_ARRAY() helper
  nvmem: sec-qfprom: Add Qualcomm secure QFPROM support
  dt-bindings: nvmem: sec-qfprom: Add bindings for secure qfprom
  dt-bindings: nvmem: Add compatible for QCM2290
  nvmem: Kconfig: Fix typo "drive" -> "driver"
  nvmem: Explicitly include correct DT includes
  nvmem: add new NXP QorIQ eFuse driver
  dt-bindings: nvmem: Add t1023-sfp efuse support
  dt-bindings: nvmem: qfprom: Add compatible for MSM8226
  nvmem: uniphier: Use devm_platform_get_and_ioremap_resource()
  nvmem: qfprom: do some cleanup
  nvmem: stm32-romem: Use devm_platform_get_and_ioremap_resource()
  nvmem: rockchip-efuse: Use devm_platform_get_and_ioremap_resource()
  nvmem: meson-mx-efuse: Convert to devm_platform_ioremap_resource()
  nvmem: lpc18xx_otp: Convert to devm_platform_ioremap_resource()
  nvmem: brcm_nvram: Use devm_platform_get_and_ioremap_resource()
  ...
2023-09-01 09:53:54 -07:00
Linus Torvalds
28a4f91f5f Driver core changes for 6.6-rc1
Here is a small set of driver core updates and additions for 6.6-rc1.
 
 Included in here are:
   - stable kernel documentation updates
   - class structure const work from Ivan on various subsystems
   - kernfs tweaks
   - driver core tests!
   - kobject sanity cleanups
   - kobject structure reordering to save space
   - driver core error code handling fixups
   - other minor driver core cleanups
 
 All of these have been in linux-next for a while with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is a small set of driver core updates and additions for 6.6-rc1.

  Included in here are:

   - stable kernel documentation updates

   - class structure const work from Ivan on various subsystems

   - kernfs tweaks

   - driver core tests!

   - kobject sanity cleanups

   - kobject structure reordering to save space

   - driver core error code handling fixups

   - other minor driver core cleanups

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  driver core: Call in reversed order in device_platform_notify_remove()
  driver core: Return proper error code when dev_set_name() fails
  kobject: Remove redundant checks for whether ktype is NULL
  kobject: Add sanity check for kset->kobj.ktype in kset_register()
  drivers: base: test: Add missing MODULE_* macros to root device tests
  drivers: base: test: Add missing MODULE_* macros for platform devices tests
  drivers: base: Free devm resources when unregistering a device
  drivers: base: Add basic devm tests for platform devices
  drivers: base: Add basic devm tests for root devices
  kernfs: fix missing kernfs_iattr_rwsem locking
  docs: stable-kernel-rules: mention that regressions must be prevented
  docs: stable-kernel-rules: fine-tune various details
  docs: stable-kernel-rules: make the examples for option 1 a proper list
  docs: stable-kernel-rules: move text around to improve flow
  docs: stable-kernel-rules: improve structure by changing headlines
  base/node: Remove duplicated include
  kernfs: attach uuid for every kernfs and report it in fsid
  kernfs: add stub helper for kernfs_generic_poll()
  x86/resctrl: make pseudo_lock_class a static const structure
  x86/MSR: make msr_class a static const structure
  ...
2023-09-01 09:43:18 -07:00
Jim Mattson
18032b47ad x86/fpu/xstate: Fix PKRU covert channel
When XCR0[9] is set, PKRU can be read and written from userspace with
XSAVE and XRSTOR, even when CR4.PKE is clear.

Clear XCR0[9] when protection keys are disabled.

Reported-by: Tavis Ormandy <taviso@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20230831043228.1194256-1-jmattson@google.com
2023-08-31 23:29:49 +02:00
Linus Torvalds
df57721f9a Add x86 shadow stack support
Convert IBT selftest to asm to fix objtool warning
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Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 shadow stack support from Dave Hansen:
 "This is the long awaited x86 shadow stack support, part of Intel's
  Control-flow Enforcement Technology (CET).

  CET consists of two related security features: shadow stacks and
  indirect branch tracking. This series implements just the shadow stack
  part of this feature, and just for userspace.

  The main use case for shadow stack is providing protection against
  return oriented programming attacks. It works by maintaining a
  secondary (shadow) stack using a special memory type that has
  protections against modification. When executing a CALL instruction,
  the processor pushes the return address to both the normal stack and
  to the special permission shadow stack. Upon RET, the processor pops
  the shadow stack copy and compares it to the normal stack copy.

  For more information, refer to the links below for the earlier
  versions of this patch set"

Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/

* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  x86/shstk: Change order of __user in type
  x86/ibt: Convert IBT selftest to asm
  x86/shstk: Don't retry vm_munmap() on -EINTR
  x86/kbuild: Fix Documentation/ reference
  x86/shstk: Move arch detail comment out of core mm
  x86/shstk: Add ARCH_SHSTK_STATUS
  x86/shstk: Add ARCH_SHSTK_UNLOCK
  x86: Add PTRACE interface for shadow stack
  selftests/x86: Add shadow stack test
  x86/cpufeatures: Enable CET CR4 bit for shadow stack
  x86/shstk: Wire in shadow stack interface
  x86: Expose thread features in /proc/$PID/status
  x86/shstk: Support WRSS for userspace
  x86/shstk: Introduce map_shadow_stack syscall
  x86/shstk: Check that signal frame is shadow stack mem
  x86/shstk: Check that SSP is aligned on sigreturn
  x86/shstk: Handle signals for shadow stack
  x86/shstk: Introduce routines modifying shstk
  x86/shstk: Handle thread shadow stack
  x86/shstk: Add user-mode shadow stack support
  ...
2023-08-31 12:20:12 -07:00
Vincenzo Palazzo
d87e89c273 x86/irq/i8259: Fix kernel-doc annotation warning
Fix this warning:

  arch/x86/kernel/i8259.c:235: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
   * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
    CC      arch/x86/kernel/irqinit.o

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230830131211.88226-1-vincenzopalazzodev@gmail.com
2023-08-31 20:43:30 +02:00
Dave Hansen
c9f4c45c8e x86/speculation: Mark all Skylake CPUs as vulnerable to GDS
The Gather Data Sampling (GDS) vulnerability is common to all Skylake
processors.  However, the "client" Skylakes* are now in this list:

	https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html

which means they are no longer included for new vulnerabilities here:

	https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html

or in other GDS documentation.  Thus, they were not included in the
original GDS mitigation patches.

Mark SKYLAKE and SKYLAKE_L as vulnerable to GDS to match all the
other Skylake CPUs (which include Kaby Lake).  Also group the CPUs
so that the ones that share the exact same vulnerabilities are next
to each other.

Last, move SRBDS to the end of each line.  This makes it clear at a
glance that SKYLAKE_X is unique.  Of the five Skylakes, it is the
only "server" CPU and has a different implementation from the
clients of the "special register" hardware, making it immune to SRBDS.

This makes the diff much harder to read, but the resulting table is
worth it.

I very much appreciate the report from Michael Zhivich about this
issue.  Despite what level of support a hardware vendor is providing,
the kernel very much needs an accurate and up-to-date list of
vulnerable CPUs.  More reports like this are very welcome.

* Client Skylakes are CPUID 406E3/506E3 which is family 6, models
  0x4E and 0x5E, aka INTEL_FAM6_SKYLAKE and INTEL_FAM6_SKYLAKE_L.

Reported-by: Michael Zhivich <mzhivich@akamai.com>
Fixes: 8974eb5882 ("x86/speculation: Add Gather Data Sampling mitigation")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
2023-08-31 20:20:31 +02:00
Sean Christopherson
d10f3780bc KVM: x86/mmu: Include mmu.h in spte.h
Explicitly include mmu.h in spte.h instead of relying on the "parent" to
include mmu.h.  spte.h references a variety of macros and variables that
are defined/declared in mmu.h, and so including spte.h before (or instead
of) mmu.h will result in build errors, e.g.

  arch/x86/kvm/mmu/spte.h: In function ‘is_mmio_spte’:
  arch/x86/kvm/mmu/spte.h:242:23: error: ‘enable_mmio_caching’ undeclared
    242 |                likely(enable_mmio_caching);
        |                       ^~~~~~~~~~~~~~~~~~~

  arch/x86/kvm/mmu/spte.h: In function ‘is_large_pte’:
  arch/x86/kvm/mmu/spte.h:302:22: error: ‘PT_PAGE_SIZE_MASK’ undeclared
    302 |         return pte & PT_PAGE_SIZE_MASK;
        |                      ^~~~~~~~~~~~~~~~~

  arch/x86/kvm/mmu/spte.h: In function ‘is_dirty_spte’:
  arch/x86/kvm/mmu/spte.h:332:56: error: ‘PT_WRITABLE_MASK’ undeclared
    332 |         return dirty_mask ? spte & dirty_mask : spte & PT_WRITABLE_MASK;
        |                                                        ^~~~~~~~~~~~~~~~

Fixes: 5a9624affe ("KVM: mmu: extract spte.h and spte.c")
Link: https://lore.kernel.org/r/20230808224059.2492476-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:25 -04:00
Sean Christopherson
0e3223d8d0 KVM: x86/mmu: Use dummy root, backed by zero page, for !visible guest roots
When attempting to allocate a shadow root for a !visible guest root gfn,
e.g. that resides in MMIO space, load a dummy root that is backed by the
zero page instead of immediately synthesizing a triple fault shutdown
(using the zero page ensures any attempt to translate memory will generate
a !PRESENT fault and thus VM-Exit).

Unless the vCPU is racing with memslot activity, KVM will inject a page
fault due to not finding a visible slot in FNAME(walk_addr_generic), i.e.
the end result is mostly same, but critically KVM will inject a fault only
*after* KVM runs the vCPU with the bogus root.

Waiting to inject a fault until after running the vCPU fixes a bug where
KVM would bail from nested VM-Enter if L1 tried to run L2 with TDP enabled
and a !visible root.  Even though a bad root will *probably* lead to
shutdown, (a) it's not guaranteed and (b) the CPU won't read the
underlying memory until after VM-Enter succeeds.  E.g. if L1 runs L2 with
a VMX preemption timer value of '0', then architecturally the preemption
timer VM-Exit is guaranteed to occur before the CPU executes any
instruction, i.e. before the CPU needs to translate a GPA to a HPA (so
long as there are no injected events with higher priority than the
preemption timer).

If KVM manages to get to FNAME(fetch) with a dummy root, e.g. because
userspace created a memslot between installing the dummy root and handling
the page fault, simply unload the MMU to allocate a new root and retry the
instruction.  Use KVM_REQ_MMU_FREE_OBSOLETE_ROOTS to drop the root, as
invoking kvm_mmu_free_roots() while holding mmu_lock would deadlock, and
conceptually the dummy root has indeeed become obsolete.  The only
difference versus existing usage of KVM_REQ_MMU_FREE_OBSOLETE_ROOTS is
that the root has become obsolete due to memslot *creation*, not memslot
deletion or movement.

Reported-by: Reima Ishii <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:24 -04:00
Sean Christopherson
b5b359ac30 KVM: x86/mmu: Disallow guest from using !visible slots for page tables
Explicitly inject a page fault if guest attempts to use a !visible gfn
as a page table.  kvm_vcpu_gfn_to_hva_prot() will naturally handle the
case where there is no memslot, but doesn't catch the scenario where the
gfn points at a KVM-internal memslot.

Letting the guest backdoor its way into accessing KVM-internal memslots
isn't dangerous on its own, e.g. at worst the guest can crash itself, but
disallowing the behavior will simplify fixing how KVM handles !visible
guest root gfns (immediately synthesizing a triple fault when loading the
root is architecturally wrong).

Link: https://lore.kernel.org/r/20230729005200.1057358-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:23 -04:00
Sean Christopherson
2c6d4c27b9 KVM: x86/mmu: Harden TDP MMU iteration against root w/o shadow page
Explicitly check that tdp_iter_start() is handed a valid shadow page
to harden KVM against bugs, e.g. if KVM calls into the TDP MMU with an
invalid or shadow MMU root (which would be a fatal KVM bug), the shadow
page pointer will be NULL.

Opportunistically stop the TDP MMU iteration instead of continuing on
with garbage if the incoming root is bogus.  Attempting to walk a garbage
root is more likely to caused major problems than doing nothing.

Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:22 -04:00
Sean Christopherson
c30e000e69 KVM: x86/mmu: Harden new PGD against roots without shadow pages
Harden kvm_mmu_new_pgd() against NULL pointer dereference bugs by sanity
checking that the target root has an associated shadow page prior to
dereferencing said shadow page.  The code in question is guaranteed to
only see roots with shadow pages as fast_pgd_switch() explicitly frees the
current root if it doesn't have a shadow page, i.e. is a PAE root, and
that in turn prevents valid roots from being cached, but that's all very
subtle.

Link: https://lore.kernel.org/r/20230729005200.1057358-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:21 -04:00
Sean Christopherson
c5f2d5645f KVM: x86/mmu: Add helper to convert root hpa to shadow page
Add a dedicated helper for converting a root hpa to a shadow page in
anticipation of using a "dummy" root to handle the scenario where KVM
needs to load a valid shadow root (from hardware's perspective), but
the guest doesn't have a visible root to shadow.  Similar to PAE roots,
the dummy root won't have an associated kvm_mmu_page and will need special
handling when finding a shadow page given a root.

Opportunistically retrieve the root shadow page in kvm_mmu_sync_roots()
*after* verifying the root is unsync (the dummy root can never be unsync).

Link: https://lore.kernel.org/r/20230729005200.1057358-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:20 -04:00
Sean Christopherson
f22b1e8500 KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers
Get/put references to KVM when a page-track notifier is (un)registered
instead of relying on the caller to do so.  Forcing the caller to do the
bookkeeping is unnecessary and adds one more thing for users to get
wrong, e.g. see commit 9ed1fdee9e ("drm/i915/gvt: Get reference to KVM
iff attachment to VM is successful").

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-29-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:19 -04:00
Sean Christopherson
96316a0670 KVM: x86/mmu: Drop @slot param from exported/external page-track APIs
Refactor KVM's exported/external page-track, a.k.a. write-track, APIs
to take only the gfn and do the required memslot lookup in KVM proper.
Forcing users of the APIs to get the memslot unnecessarily bleeds
KVM internals into KVMGT and complicates usage of the APIs.

No functional change intended.

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-28-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:18 -04:00
Sean Christopherson
427c76aed2 KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled
Bug the VM if something attempts to write-track a gfn, but write-tracking
isn't enabled.  The VM is doomed (and KVM has an egregious bug) if KVM or
KVMGT wants to shadow guest page tables but can't because write-tracking
isn't enabled.

Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-27-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:17 -04:00
Sean Christopherson
e18c5429e0 KVM: x86/mmu: Assert that correct locks are held for page write-tracking
When adding/removing gfns to/from write-tracking, assert that mmu_lock
is held for write, and that either slots_lock or kvm->srcu is held.
mmu_lock must be held for write to protect gfn_write_track's refcount,
and SRCU or slots_lock must be held to protect the memslot itself.

Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-26-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:16 -04:00
Sean Christopherson
7b574863e7 KVM: x86/mmu: Rename page-track APIs to reflect the new reality
Rename the page-track APIs to capture that they're all about tracking
writes, now that the facade of supporting multiple modes is gone.

Opportunstically replace "slot" with "gfn" in anticipation of removing
the @slot param from the external APIs.

No functional change intended.

Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-25-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:15 -04:00
Sean Christopherson
338068b5be KVM: x86/mmu: Drop infrastructure for multiple page-track modes
Drop "support" for multiple page-track modes, as there is no evidence
that array-based and refcounted metadata is the optimal solution for
other modes, nor is there any evidence that other use cases, e.g. for
access-tracking, will be a good fit for the page-track machinery in
general.

E.g. one potential use case of access-tracking would be to prevent guest
access to poisoned memory (from the guest's perspective).  In that case,
the number of poisoned pages is likely to be a very small percentage of
the guest memory, and there is no need to reference count the number of
access-tracking users, i.e. expanding gfn_track[] for a new mode would be
grossly inefficient.  And for poisoned memory, host userspace would also
likely want to trap accesses, e.g. to inject #MC into the guest, and that
isn't currently supported by the page-track framework.

A better alternative for that poisoned page use case is likely a
variation of the proposed per-gfn attributes overlay (linked), which
would allow efficiently tracking the sparse set of poisoned pages, and by
default would exit to userspace on access.

Link: https://lore.kernel.org/all/Y2WB48kD0J4VGynX@google.com
Cc: Ben Gardon <bgardon@google.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:14 -04:00
Sean Christopherson
e998fb1a30 KVM: x86/mmu: Use page-track notifiers iff there are external users
Disable the page-track notifier code at compile time if there are no
external users, i.e. if CONFIG_KVM_EXTERNAL_WRITE_TRACKING=n.  KVM itself
now hooks emulated writes directly instead of relying on the page-track
mechanism.

Provide a stub for "struct kvm_page_track_notifier_node" so that including
headers directly from the command line, e.g. for testing include guards,
doesn't fail due to a struct having an incomplete type.

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-23-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:14 -04:00
Sean Christopherson
58ea7cf700 KVM: x86/mmu: Move KVM-only page-track declarations to internal header
Bury the declaration of the page-track helpers that are intended only for
internal KVM use in a "private" header.  In addition to guarding against
unwanted usage of the internal-only helpers, dropping their definitions
avoids exposing other structures that should be KVM-internal, e.g. for
memslots.  This is a baby step toward making kvm_host.h a KVM-internal
header in the very distant future.

Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:08:13 -04:00
Yan Zhao
d104d5bbbc KVM: x86: Remove the unused page-track hook track_flush_slot()
Remove ->track_remove_slot(), there are no longer any users and it's
unlikely a "flush" hook will ever be the correct API to provide to an
external page-track user.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-21-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:07:26 -04:00
Yan Zhao
b83ab124de KVM: x86: Add a new page-track hook to handle memslot deletion
Add a new page-track hook, track_remove_region(), that is called when a
memslot DELETE operation is about to be committed.  The "remove" hook
will be used by KVMGT and will effectively replace the existing
track_flush_slot() altogether now that KVM itself doesn't rely on the
"flush" hook either.

The "flush" hook is flawed as it's invoked before the memslot operation
is guaranteed to succeed, i.e. KVM might ultimately keep the existing
memslot without notifying external page track users, a.k.a. KVMGT.  In
practice, this can't currently happen on x86, but there are no guarantees
that won't change in the future, not to mention that "flush" does a very
poor job of describing what is happening.

Pass in the gfn+nr_pages instead of the slot itself so external users,
i.e. KVMGT, don't need to exposed to KVM internals (memslots).  This will
help set the stage for additional cleanups to the page-track APIs.

Opportunistically align the existing srcu_read_lock_held() usage so that
the new case doesn't stand out like a sore thumb (and not aligning the
new code makes bots unhappy).

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:07:25 -04:00
Sean Christopherson
c70934e0ab KVM: x86: Reject memslot MOVE operations if KVMGT is attached
Disallow moving memslots if the VM has external page-track users, i.e. if
KVMGT is being used to expose a virtual GPU to the guest, as KVMGT doesn't
correctly handle moving memory regions.

Note, this is potential ABI breakage!  E.g. userspace could move regions
that aren't shadowed by KVMGT without harming the guest.  However, the
only known user of KVMGT is QEMU, and QEMU doesn't move generic memory
regions.  KVM's own support for moving memory regions was also broken for
multiple years (albeit for an edge case, but arguably moving RAM is
itself an edge case), e.g. see commit edd4fa37ba ("KVM: x86: Allocate
new rmap and large page tracking when moving memslot").

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-17-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 14:07:23 -04:00
Sean Christopherson
b271e17def KVM: drm/i915/gvt: Drop @vcpu from KVM's ->track_write() hook
Drop @vcpu from KVM's ->track_write() hook provided for external users of
the page-track APIs now that KVM itself doesn't use the page-track
mechanism.

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-16-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 13:49:01 -04:00
Sean Christopherson
932844462a KVM: x86/mmu: Don't bounce through page-track mechanism for guest PTEs
Don't use the generic page-track mechanism to handle writes to guest PTEs
in KVM's MMU.  KVM's MMU needs access to information that should not be
exposed to external page-track users, e.g. KVM needs (for some definitions
of "need") the vCPU to query the current paging mode, whereas external
users, i.e. KVMGT, have no ties to the current vCPU and so should never
need the vCPU.

Moving away from the page-track mechanism will allow dropping use of the
page-track mechanism for KVM's own MMU, and will also allow simplifying
and cleaning up the page-track APIs.

Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-15-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 13:49:00 -04:00
Sean Christopherson
eeb87272a3 KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot change
Call kvm_mmu_zap_all_fast() directly when flushing a memslot instead of
bouncing through the page-track mechanism.  KVM (unfortunately) needs to
zap and flush all page tables on memslot DELETE/MOVE irrespective of
whether KVM is shadowing guest page tables.

This will allow changing KVM to register a page-track notifier on the
first shadow root allocation, and will also allow deleting the misguided
kvm_page_track_flush_slot() hook itself once KVM-GT also moves to a
different method for reacting to memslot changes.

No functional change intended.

Cc: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20221110014821.1548347-2-seanjc@google.com
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 13:49:00 -04:00
Sean Christopherson
db0d70e610 KVM: x86/mmu: Move kvm_arch_flush_shadow_{all,memslot}() to mmu.c
Move x86's implementation of kvm_arch_flush_shadow_{all,memslot}() into
mmu.c, and make kvm_mmu_zap_all() static as it was globally visible only
for kvm_arch_flush_shadow_all().  This will allow refactoring
kvm_arch_flush_shadow_memslot() to call kvm_mmu_zap_all() directly without
having to expose kvm_mmu_zap_all_fast() outside of mmu.c.  Keeping
everything in mmu.c will also likely simplify supporting TDX, which
intends to do zap only relevant SPTEs on memslot updates.

No functional change intended.

Suggested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-08-31 13:48:59 -04:00