When the TSC_AUX MSR is virtualized, the TSC_AUX value is swap type "B"
within the VMSA. This means that the guest value is loaded on VMRUN and
the host value is restored from the host save area on #VMEXIT.
Since the value is restored on #VMEXIT, the KVM user return MSR support
for TSC_AUX can be replaced by populating the host save area with the
current host value of TSC_AUX. And, since TSC_AUX is not changed by Linux
post-boot, the host save area can be set once in svm_hardware_enable().
This eliminates the two WRMSR instructions associated with the user return
MSR support.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <d381de38eb0ab6c9c93dda8503b72b72546053d7.1694811272.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The checks for virtualizing TSC_AUX occur during the vCPU reset processing
path. However, at the time of initial vCPU reset processing, when the vCPU
is first created, not all of the guest CPUID information has been set. In
this case the RDTSCP and RDPID feature support for the guest is not in
place and so TSC_AUX virtualization is not established.
This continues for each vCPU created for the guest. On the first boot of
an AP, vCPU reset processing is executed as a result of an APIC INIT
event, this time with all of the guest CPUID information set, resulting
in TSC_AUX virtualization being enabled, but only for the APs. The BSP
always sees a TSC_AUX value of 0 which probably went unnoticed because,
at least for Linux, the BSP TSC_AUX value is 0.
Move the TSC_AUX virtualization enablement out of the init_vmcb() path and
into the vcpu_after_set_cpuid() path to allow for proper initialization of
the support after the guest CPUID information has been set.
With the TSC_AUX virtualization support now in the vcpu_set_after_cpuid()
path, the intercepts must be either cleared or set based on the guest
CPUID input.
Fixes: 296d5a17e7 ("KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <4137fbcb9008951ab5f0befa74a0399d2cce809a.1694811272.git.thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Misc cleanups
- Retry APIC optimized 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 can diverge from the default iff TSC scaling is enabled, and clean
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
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Merge tag 'kvm-x86-misc-6.6' of https://github.com/kvm-x86/linux into HEAD
KVM x86 changes for 6.6:
- Misc cleanups
- Retry APIC optimized 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 can diverge from the default iff TSC scaling is enabled, and clean
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
- Add support for SEV-ES DebugSwap, i.e. allow 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)
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Merge tag 'kvm-x86-svm-6.6' of https://github.com/kvm-x86/linux into HEAD
KVM: x86: SVM changes for 6.6:
- Add support for SEV-ES DebugSwap, i.e. allow 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)
Disallow SEV (and beyond) if nrips is disabled via module param, as KVM
can't read guest memory to partially emulate and skip an instruction. All
CPUs that support SEV support NRIPS, i.e. this is purely stopping the user
from shooting themselves in the foot.
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230825013621.2845700-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Don't inject a #UD if KVM attempts to "emulate" to skip an instruction
for an SEV guest, and instead resume the guest and hope that it can make
forward progress. When commit 04c40f344d ("KVM: SVM: Inject #UD on
attempted emulation for SEV guest w/o insn buffer") added the completely
arbitrary #UD behavior, there were no known scenarios where a well-behaved
guest would induce a VM-Exit that triggered emulation, i.e. it was thought
that injecting #UD would be helpful.
However, now that KVM (correctly) attempts to re-inject INT3/INTO, e.g. if
a #NPF is encountered when attempting to deliver the INT3/INTO, an SEV
guest can trigger emulation without a buffer, through no fault of its own.
Resuming the guest and retrying the INT3/INTO is architecturally wrong,
e.g. the vCPU will incorrectly re-hit code #DBs, but for SEV guests there
is literally no other option that has a chance of making forward progress.
Drop the #UD injection for all "skip" emulation, not just those related to
INT3/INTO, even though that means that the guest will likely end up in an
infinite loop instead of getting a #UD (the vCPU may also crash, e.g. if
KVM emulated everything about an instruction except for advancing RIP).
There's no evidence that suggests that an unexpected #UD is actually
better than hanging the vCPU, e.g. a soft-hung vCPU can still respond to
IRQs and NMIs to generate a backtrace.
Reported-by: Wu Zongyo <wuzongyo@mail.ustc.edu.cn>
Closes: https://lore.kernel.org/all/8eb933fd-2cf3-d7a9-32fe-2a1d82eac42a@mail.ustc.edu.cn
Fixes: 6ef88d6e36 ("KVM: SVM: Re-inject INT3/INTO instead of retrying the instruction")
Cc: stable@vger.kernel.org
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230825013621.2845700-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "virtual NMI exposed to L1" via a governed feature flag instead of
using a dedicated bit/flag in vcpu_svm.
Note, checking KVM's capabilities instead of the "vnmi" param means that
the code isn't strictly equivalent, as vnmi_enabled could have been set
if nested=false where as that the governed feature cannot. But that's a
glorified nop as the feature/flag is consumed only by paths that are
gated by nSVM being enabled.
Link: https://lore.kernel.org/r/20230815203653.519297-15-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "virtual GIF exposed to L1" via a governed feature flag instead of
using a dedicated bit/flag in vcpu_svm.
Note, checking KVM's capabilities instead of the "vgif" param means that
the code isn't strictly equivalent, as vgif_enabled could have been set
if nested=false where as that the governed feature cannot. But that's a
glorified nop as the feature/flag is consumed only by paths that are
Link: https://lore.kernel.org/r/20230815203653.519297-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "Pause Filtering is exposed to L1" via governed feature flags
instead of using dedicated bits/flags in vcpu_svm.
No functional change intended.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "LBR virtualization exposed to L1" via a governed feature flag
instead of using a dedicated bit/flag in vcpu_svm.
Note, checking KVM's capabilities instead of the "lbrv" param means that
the code isn't strictly equivalent, as lbrv_enabled could have been set
if nested=false where as that the governed feature cannot. But that's a
glorified nop as the feature/flag is consumed only by paths that are
gated by nSVM being enabled.
Link: https://lore.kernel.org/r/20230815203653.519297-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "virtual VMSAVE/VMLOAD exposed to L1" via a governed feature flag
instead of using a dedicated bit/flag in vcpu_svm.
Opportunistically add a comment explaining why KVM disallows virtual
VMLOAD/VMSAVE when the vCPU model is Intel.
No functional change intended.
Link: https://lore.kernel.org/r/20230815203653.519297-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "TSC scaling exposed to L1" via a governed feature flag instead of
using a dedicated bit/flag in vcpu_svm.
Note, this fixes a benign bug where KVM would mark TSC scaling as exposed
to L1 even if overall nested SVM supported is disabled, i.e. KVM would let
L1 write MSR_AMD64_TSC_RATIO even when KVM didn't advertise TSCRATEMSR
support to userspace.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Track "NRIPS exposed to L1" via a governed feature flag instead of using
a dedicated bit/flag in vcpu_svm.
No functional change intended.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use the governed feature framework to track if XSAVES is "enabled", i.e.
if XSAVES can be used by the guest. Add a comment in the SVM code to
explain the very unintuitive logic of deliberately NOT checking if XSAVES
is enumerated in the guest CPUID model.
No functional change intended.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Initially, it was thought that doing an innocuous division in the #DE
handler would take care to prevent any leaking of old data from the
divider but by the time the fault is raised, the speculation has already
advanced too far and such data could already have been used by younger
operations.
Therefore, do the innocuous division on every exit to userspace so that
userspace doesn't see any potentially old data from integer divisions in
kernel space.
Do the same before VMRUN too, to protect host data from leaking into the
guest too.
Fixes: 77245f1c3c ("x86/CPU/AMD: Do not leak quotient data after a division by 0")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230811213824.10025-1-bp@alien8.de
vulnerability on AMD processors. In short, this is yet another issue
where userspace poisons a microarchitectural structure which can then be
used to leak privileged information through a side channel.
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Merge tag 'x86_bugs_srso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/srso fixes from Borislav Petkov:
"Add a mitigation for the speculative RAS (Return Address Stack)
overflow vulnerability on AMD processors.
In short, this is yet another issue where userspace poisons a
microarchitectural structure which can then be used to leak privileged
information through a side channel"
* tag 'x86_bugs_srso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/srso: Tie SBPB bit setting to microcode patch detection
x86/srso: Add a forgotten NOENDBR annotation
x86/srso: Fix return thunks in generated code
x86/srso: Add IBPB on VMEXIT
x86/srso: Add IBPB
x86/srso: Add SRSO_NO support
x86/srso: Add IBPB_BRTYPE support
x86/srso: Add a Speculative RAS Overflow mitigation
x86/bugs: Increase the x86 bugs vector size to two u32s
Skip writes to MSR_AMD64_TSC_RATIO that are done in the context of a vCPU
if guest state isn't loaded, i.e. if KVM will update MSR_AMD64_TSC_RATIO
during svm_prepare_switch_to_guest() before entering the guest. Checking
guest_state_loaded may or may not be a net positive for performance as
the current_tsc_ratio cache will optimize away duplicate WRMSRs in the
vast majority of scenarios. However, the cost of the check is negligible,
and the real motivation is to document that KVM needs to load the vCPU's
value only when running the vCPU.
Link: https://lore.kernel.org/r/20230729011608.1065019-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Drop the @offset and @multiplier params from the kvm_x86_ops hooks for
propagating TSC offsets/multipliers into hardware, and instead have the
vendor implementations pull the information directly from the vCPU
structure. The respective vCPU fields _must_ be written at the same
time in order to maintain consistent state, i.e. it's not random luck
that the value passed in by all callers is grabbed from the vCPU.
Explicitly grabbing the value from the vCPU field in SVM's implementation
in particular will allow for additional cleanup without introducing even
more subtle dependencies. Specifically, SVM can skip the WRMSR if guest
state isn't loaded, i.e. svm_prepare_switch_to_guest() will load the
correct value for the vCPU prior to entering the guest.
This also reconciles KVM's handling of related values that are stored in
the vCPU, as svm_write_tsc_offset() already assumes/requires the caller
to have updated l1_tsc_offset.
Link: https://lore.kernel.org/r/20230729011608.1065019-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Explicitly disable preemption when writing MSR_AMD64_TSC_RATIO only in the
"outer" helper, as all direct callers of the "inner" helper now run with
preemption already disabled. And that isn't a coincidence, as the outer
helper requires a vCPU and is intended to be used when modifying guest
state and/or emulating guest instructions, which are typically done with
preemption enabled.
Direct use of the inner helper should be extremely limited, as the only
time KVM should modify MSR_AMD64_TSC_RATIO without a vCPU is when
sanitizing the MSR for a specific pCPU (currently done when {en,dis}abling
disabling SVM). The other direct caller is svm_prepare_switch_to_guest(),
which does have a vCPU, but is a one-off special case: KVM is about to
enter the guest on a specific pCPU and thus must have preemption disabled.
Link: https://lore.kernel.org/r/20230729011608.1065019-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
When emulating nested SVM transitions, use the outer helper for writing
the TSC multiplier for L2. Using the inner helper only for one-off cases,
i.e. for paths where KVM is NOT emulating or modifying vCPU state, will
allow for multiple cleanups:
- Explicitly disabling preemption only in the outer helper
- Getting the multiplier from the vCPU field in the outer helper
- Skipping the WRMSR in the outer helper if guest state isn't loaded
Opportunistically delete an extra newline.
No functional change intended.
Link: https://lore.kernel.org/r/20230729011608.1065019-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Now that kvm_rebooting is guaranteed to be true prior to disabling SVM
in an emergency, use the existing stgi() helper instead of open coding
STGI. In effect, eat faults on STGI if and only if kvm_rebooting==true.
Link: https://lore.kernel.org/r/20230721201859.2307736-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Set kvm_rebooting when virtualization is disabled in an emergency so that
KVM eats faults on virtualization instructions even if kvm_reboot() isn't
reached.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-18-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move cpu_svm_disable() into KVM proper now that all hardware
virtualization management is routed through KVM. Remove the now-empty
virtext.h.
No functional change intended.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-17-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Check "this" CPU instead of the boot CPU when querying SVM support so that
the per-CPU checks done during hardware enabling actually function as
intended, i.e. will detect issues where SVM isn't support on all CPUs.
Disable migration for the use from svm_init() mostly so that the standard
accessors for the per-CPU data can be used without getting yelled at by
CONFIG_DEBUG_PREEMPT=y sanity checks. Preventing the "disabled by BIOS"
error message from reporting the wrong CPU is largely a bonus, as ensuring
a stable CPU during module load is a non-goal for KVM.
Link: https://lore.kernel.org/all/ZAdxNgv0M6P63odE@google.com
Cc: Kai Huang <kai.huang@intel.com>
Cc: Chao Gao <chao.gao@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-15-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Fold the guts of cpu_has_svm() into kvm_is_svm_supported(), its sole
remaining user.
No functional change intended.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use the virt callback to disable SVM (and set GIF=1) during an emergency
instead of blindly attempting to disable SVM. Like the VMX case, if a
hypervisor, i.e. KVM, isn't loaded/active, SVM can't be in use.
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use the recently introduced svm_get_lbr_vmcb() instead an open coded
equivalent to retrieve the target VMCB when emulating writes to
MSR_IA32_DEBUGCTLMSR.
No functional change intended.
Link: https://lore.kernel.org/r/20230607203519.1570167-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Clean up the enable_lbrv computation in svm_update_lbrv() to consolidate
the logic for computing enable_lbrv into a single statement, and to remove
the coding style violations (lack of curly braces on nested if).
No functional change intended.
Link: https://lore.kernel.org/r/20230607203519.1570167-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Refactor KVM's handling of LBR MSRs on SVM to avoid a second layer of
case statements, and thus eliminate a dead KVM_BUG() call, which (a) will
never be hit in the current code base and (b) if a future commit breaks
things, will never fire as KVM passes "false" instead "true" or '1' for
the KVM_BUG() condition.
Reported-by: Michal Luczaj <mhal@rbox.co>
Cc: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230607203519.1570167-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reject KVM_SET_SREGS{2} with -EINVAL if the incoming CR0 is invalid,
e.g. due to setting bits 63:32, illegal combinations, or to a value that
isn't allowed in VMX (non-)root mode. The VMX checks in particular are
"fun" as failure to disallow Real Mode for an L2 that is configured with
unrestricted guest disabled, when KVM itself has unrestricted guest
enabled, will result in KVM forcing VM86 mode to virtual Real Mode for
L2, but then fail to unwind the related metadata when synthesizing a
nested VM-Exit back to L1 (which has unrestricted guest enabled).
Opportunistically fix a benign typo in the prototype for is_valid_cr4().
Cc: stable@vger.kernel.org
Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000f316b705fdf6e2b4@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230613203037.1968489-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that handle_fastpath_set_msr_irqoff() acquires kvm->srcu, i.e. allows
dereferencing memslots during WRMSR emulation, drop the requirement that
"next RIP" is valid. In hindsight, acquiring kvm->srcu would have been a
better fix than avoiding the pastpath, but at the time it was thought that
accessing SRCU-protected data in the fastpath was a one-off edge case.
This reverts commit 5c30e8101e.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230721224337.2335137-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bail early from svm_enable_nmi_window() for SEV-ES guests without trying
to enable single-step of the guest, as single-stepping an SEV-ES guest is
impossible and the guest is responsible for *telling* KVM when it is ready
for an new NMI to be injected.
Functionally, setting TF and RF in svm->vmcb->save.rflags is benign as the
field is ignored by hardware, but it's all kinds of confusing.
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-10-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Immediately mark NMIs as unmasked in response to #VMGEXIT(NMI complete)
instead of setting awaiting_iret_completion and waiting until the *next*
VM-Exit to unmask NMIs. The whole point of "NMI complete" is that the
guest is responsible for telling the hypervisor when it's safe to inject
an NMI, i.e. there's no need to wait. And because there's no IRET to
single-step, the next VM-Exit could be a long time coming, i.e. KVM could
incorrectly hold an NMI pending for far longer than what is required and
expected.
Opportunistically fix a stale reference to HF_IRET_MASK.
Fixes: 916b54a768 ("KVM: x86: Move HF_NMI_MASK and HF_IRET_MASK into "struct vcpu_svm"")
Fixes: 4444dfe405 ("KVM: SVM: Add NMI support for an SEV-ES guest")
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-9-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Currently SVM setup is done sequentially in
init_vmcb() -> sev_init_vmcb() -> sev_es_init_vmcb()
and tries keeping SVM/SEV/SEV-ES bits separated. One of the exceptions
is DR intercepts which is for SEV-ES before sev_es_init_vmcb() runs.
Move the SEV-ES intercept setup to sev_es_init_vmcb(). From now on
set_dr_intercepts()/clr_dr_intercepts() handle SVM/SEV only.
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-6-aik@amd.com
[sean: drop comment about intercepting DR7]
Signed-off-by: Sean Christopherson <seanjc@google.com>
SVM/SEV enable debug registers intercepts to skip swapping DRs
on entering/exiting the guest. When the guest is in control of
debug registers (vcpu->guest_debug == 0), there is an optimisation to
reduce the number of context switches: intercepts are cleared and
the KVM_DEBUGREG_WONT_EXIT flag is set to tell KVM to do swapping
on guest enter/exit.
The same code also executes for SEV-ES, however it has no effect as
- it always takes (vcpu->guest_debug == 0) branch;
- KVM_DEBUGREG_WONT_EXIT is set but DR7 intercept is not cleared;
- vcpu_enter_guest() writes DRs but VMRUN for SEV-ES swaps them
with the values from _encrypted_ VMSA.
Be explicit about SEV-ES not supporting debug:
- return right away from dr_interception() and skip unnecessary processing;
- return an error right away from the KVM_SEV_LAUNCH_UPDATE_VMSA handler
if debugging was already enabled.
KVM_SET_GUEST_DEBUG are failing already after KVM_SEV_LAUNCH_UPDATE_VMSA
is finished due to vcpu->arch.guest_state_protected set to true.
Add WARN_ON to kvm_x86::sync_dirty_debug_regs() (saves guest DRs on
guest exit) to signify that SEV-ES won't hit that path.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-5-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Currently SVM setup is done sequentially in
init_vmcb() -> sev_init_vmcb() -> sev_es_init_vmcb() and tries
keeping SVM/SEV/SEV-ES bits separated. One of the exceptions
is #GP intercept which init_vmcb() skips setting for SEV guests and
then sev_es_init_vmcb() needlessly clears it.
Remove the SEV check from init_vmcb(). Clear the #GP intercept in
sev_init_vmcb(). SEV-ES will use the SEV setting.
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-3-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Static functions set_dr_intercepts() and clr_dr_intercepts() are only
called from SVM so move them to .c.
No functional change intended.
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-2-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add the option to flush IBPB only on VMEXIT in order to protect from
malicious guests but one otherwise trusts the software that runs on the
hypervisor.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
- Drop manual TR/TSS load after VM-Exit now that KVM uses VMLOAD for host state
- Fix a not-yet-problematic missing call to trace_kvm_exit() for VM-Exits that
are handled in the fastpath
- Print more descriptive information about the status of SEV and SEV-ES during
module load
- Assert that misc_cg_set_capacity() doesn't fail to avoid should-be-impossible
memory leaks
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Merge tag 'kvm-x86-svm-6.5' of https://github.com/kvm-x86/linux into HEAD
KVM SVM changes for 6.5:
- Drop manual TR/TSS load after VM-Exit now that KVM uses VMLOAD for host state
- Fix a not-yet-problematic missing call to trace_kvm_exit() for VM-Exits that
are handled in the fastpath
- Print more descriptive information about the status of SEV and SEV-ES during
module load
- Assert that misc_cg_set_capacity() doesn't fail to avoid should-be-impossible
memory leaks
- Add support for AMD PerfMonV2, with a variety of cleanups and minor fixes
included along the way
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Merge tag 'kvm-x86-pmu-6.5' of https://github.com/kvm-x86/linux into HEAD
KVM x86/pmu changes for 6.5:
- Add support for AMD PerfMonV2, with a variety of cleanups and minor fixes
included along the way
- Move handling of PAT out of MTRR code and dedup SVM+VMX code
- Fix output of PIC poll command emulation when there's an interrupt
- Fix a longstanding bug in the reporting of the number of entries returned by
KVM_GET_CPUID2
- Add a maintainer's handbook to document KVM x86 processes, preferred coding
style, testing expectations, etc.
- Misc cleanups
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Merge tag 'kvm-x86-misc-6.5' of https://github.com/kvm-x86/linux into HEAD
KVM x86 changes for 6.5:
* Move handling of PAT out of MTRR code and dedup SVM+VMX code
* Fix output of PIC poll command emulation when there's an interrupt
* Add a maintainer's handbook to document KVM x86 processes, preferred coding
style, testing expectations, etc.
* Misc cleanups
CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some new
performance monitoring features for AMD processors.
Bit 0 of EAX indicates support for Performance Monitoring Version 2
(PerfMonV2) features. If found to be set during PMU initialization,
the EBX bits of the same CPUID function can be used to determine
the number of available PMCs for different PMU types.
Expose the relevant bits via KVM_GET_SUPPORTED_CPUID so that
guests can make use of the PerfMonV2 features.
Co-developed-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230603011058.1038821-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Enable and advertise PERFCTR_CORE if and only if the minimum number of
required counters are available, i.e. if perf says there are less than six
general purpose counters.
Opportunistically, use kvm_cpu_cap_check_and_set() instead of open coding
the check for host support.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
[sean: massage shortlog and changelog]
Link: https://lore.kernel.org/r/20230603011058.1038821-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
As test_bit() returns bool, explicitly converting result to bool is
unnecessary. Get rid of '!!'.
No functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://lore.kernel.org/r/20230605200158.118109-1-mhal@rbox.co
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move SVM's call to trace_kvm_exit() from the "slow" VM-Exit handler to
svm_vcpu_run() so that KVM traces fastpath VM-Exits that re-enter the
guest without bouncing through the slow path. This bug is benign in the
current code base as KVM doesn't currently support any such exits on SVM.
Fixes: a9ab13ff6e ("KVM: X86: Improve latency for single target IPI fastpath")
Link: https://lore.kernel.org/r/20230602011920.787844-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
While testing Hyper-V enabled Windows Server 2019 guests on Zen4 hardware
I noticed that with vCPU count large enough (> 16) they sometimes froze at
boot.
With vCPU count of 64 they never booted successfully - suggesting some kind
of a race condition.
Since adding "vnmi=0" module parameter made these guests boot successfully
it was clear that the problem is most likely (v)NMI-related.
Running kvm-unit-tests quickly showed failing NMI-related tests cases, like
"multiple nmi" and "pending nmi" from apic-split, x2apic and xapic tests
and the NMI parts of eventinj test.
The issue was that once one NMI was being serviced no other NMI was allowed
to be set pending (NMI limit = 0), which was traced to
svm_is_vnmi_pending() wrongly testing for the "NMI blocked" flag rather
than for the "NMI pending" flag.
Fix this by testing for the right flag in svm_is_vnmi_pending().
Once this is done, the NMI-related kvm-unit-tests pass successfully and
the Windows guest no longer freezes at boot.
Fixes: fa4c027a79 ("KVM: x86: Add support for SVM's Virtual NMI")
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/be4ca192eb0c1e69a210db3009ca984e6a54ae69.1684495380.git.maciej.szmigiero@oracle.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move the common check-and-set handling of PAT MSR writes out of vendor
code and into kvm_set_msr_common(). This aligns writes with reads, which
are already handled in common code, i.e. makes the handling of reads and
writes symmetrical in common code.
Alternatively, the common handling in kvm_get_msr_common() could be moved
to vendor code, but duplicating code is generally undesirable (even though
the duplicatated code is trivial in this case), and guest writes to PAT
should be rare, i.e. the overhead of the extra function call is a
non-issue in practice.
Suggested-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230511233351.635053-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use kvm_pat_valid() directly instead of bouncing through kvm_mtrr_valid().
The PAT is not an MTRR, and kvm_mtrr_valid() just redirects to
kvm_pat_valid(), i.e. is exempt from KVM's "zap SPTEs" logic that's
needed to honor guest MTRRs when the VM has a passthrough device with
non-coherent DMA (KVM does NOT set "ignore guest PAT" in this case, and so
enables hardware virtualization of the guest's PAT, i.e. doesn't need to
manually emulate the PAT memtype).
Signed-off-by: Ke Guo <guoke@uniontech.com>
[sean: massage changelog]
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230511233351.635053-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
* More phys_to_virt conversions
* Improvement of AP management for VSIE (nested virtualization)
ARM64:
* Numerous fixes for the pathological lock inversion issue that
plagued KVM/arm64 since... forever.
* New framework allowing SMCCC-compliant hypercalls to be forwarded
to userspace, hopefully paving the way for some more features
being moved to VMMs rather than be implemented in the kernel.
* Large rework of the timer code to allow a VM-wide offset to be
applied to both virtual and physical counters as well as a
per-timer, per-vcpu offset that complements the global one.
This last part allows the NV timer code to be implemented on
top.
* A small set of fixes to make sure that we don't change anything
affecting the EL1&0 translation regime just after having having
taken an exception to EL2 until we have executed a DSB. This
ensures that speculative walks started in EL1&0 have completed.
* The usual selftest fixes and improvements.
KVM x86 changes for 6.4:
* Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled,
and by giving the guest control of CR0.WP when EPT is enabled on VMX
(VMX-only because SVM doesn't support per-bit controls)
* Add CR0/CR4 helpers to query single bits, and clean up related code
where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return
as a bool
* Move AMD_PSFD to cpufeatures.h and purge KVM's definition
* Avoid unnecessary writes+flushes when the guest is only adding new PTEs
* Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s optimizations
when emulating invalidations
* Clean up the range-based flushing APIs
* Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a single
A/D bit using a LOCK AND instead of XCHG, and skip all of the "handle
changed SPTE" overhead associated with writing the entire entry
* Track the number of "tail" entries in a pte_list_desc to avoid having
to walk (potentially) all descriptors during insertion and deletion,
which gets quite expensive if the guest is spamming fork()
* Disallow virtualizing legacy LBRs if architectural LBRs are available,
the two are mutually exclusive in hardware
* Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES)
after KVM_RUN, similar to CPUID features
* Overhaul the vmx_pmu_caps selftest to better validate PERF_CAPABILITIES
* Apply PMU filters to emulated events and add test coverage to the
pmu_event_filter selftest
x86 AMD:
* Add support for virtual NMIs
* Fixes for edge cases related to virtual interrupts
x86 Intel:
* Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if XTILE_DATA is
not being reported due to userspace not opting in via prctl()
* Fix a bug in emulation of ENCLS in compatibility mode
* Allow emulation of NOP and PAUSE for L2
* AMX selftests improvements
* Misc cleanups
MIPS:
* Constify MIPS's internal callbacks (a leftover from the hardware enabling
rework that landed in 6.3)
Generic:
* Drop unnecessary casts from "void *" throughout kvm_main.c
* Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the struct
size by 8 bytes on 64-bit kernels by utilizing a padding hole
Documentation:
* Fix goof introduced by the conversion to rST
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"s390:
- More phys_to_virt conversions
- Improvement of AP management for VSIE (nested virtualization)
ARM64:
- Numerous fixes for the pathological lock inversion issue that
plagued KVM/arm64 since... forever.
- New framework allowing SMCCC-compliant hypercalls to be forwarded
to userspace, hopefully paving the way for some more features being
moved to VMMs rather than be implemented in the kernel.
- Large rework of the timer code to allow a VM-wide offset to be
applied to both virtual and physical counters as well as a
per-timer, per-vcpu offset that complements the global one. This
last part allows the NV timer code to be implemented on top.
- A small set of fixes to make sure that we don't change anything
affecting the EL1&0 translation regime just after having having
taken an exception to EL2 until we have executed a DSB. This
ensures that speculative walks started in EL1&0 have completed.
- The usual selftest fixes and improvements.
x86:
- Optimize CR0.WP toggling by avoiding an MMU reload when TDP is
enabled, and by giving the guest control of CR0.WP when EPT is
enabled on VMX (VMX-only because SVM doesn't support per-bit
controls)
- Add CR0/CR4 helpers to query single bits, and clean up related code
where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long"
return as a bool
- Move AMD_PSFD to cpufeatures.h and purge KVM's definition
- Avoid unnecessary writes+flushes when the guest is only adding new
PTEs
- Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s
optimizations when emulating invalidations
- Clean up the range-based flushing APIs
- Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a
single A/D bit using a LOCK AND instead of XCHG, and skip all of
the "handle changed SPTE" overhead associated with writing the
entire entry
- Track the number of "tail" entries in a pte_list_desc to avoid
having to walk (potentially) all descriptors during insertion and
deletion, which gets quite expensive if the guest is spamming
fork()
- Disallow virtualizing legacy LBRs if architectural LBRs are
available, the two are mutually exclusive in hardware
- Disallow writes to immutable feature MSRs (notably
PERF_CAPABILITIES) after KVM_RUN, similar to CPUID features
- Overhaul the vmx_pmu_caps selftest to better validate
PERF_CAPABILITIES
- Apply PMU filters to emulated events and add test coverage to the
pmu_event_filter selftest
- AMD SVM:
- Add support for virtual NMIs
- Fixes for edge cases related to virtual interrupts
- Intel AMX:
- Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if
XTILE_DATA is not being reported due to userspace not opting in
via prctl()
- Fix a bug in emulation of ENCLS in compatibility mode
- Allow emulation of NOP and PAUSE for L2
- AMX selftests improvements
- Misc cleanups
MIPS:
- Constify MIPS's internal callbacks (a leftover from the hardware
enabling rework that landed in 6.3)
Generic:
- Drop unnecessary casts from "void *" throughout kvm_main.c
- Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the
struct size by 8 bytes on 64-bit kernels by utilizing a padding
hole
Documentation:
- Fix goof introduced by the conversion to rST"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (211 commits)
KVM: s390: pci: fix virtual-physical confusion on module unload/load
KVM: s390: vsie: clarifications on setting the APCB
KVM: s390: interrupt: fix virtual-physical confusion for next alert GISA
KVM: arm64: Have kvm_psci_vcpu_on() use WRITE_ONCE() to update mp_state
KVM: arm64: Acquire mp_state_lock in kvm_arch_vcpu_ioctl_vcpu_init()
KVM: selftests: Test the PMU event "Instructions retired"
KVM: selftests: Copy full counter values from guest in PMU event filter test
KVM: selftests: Use error codes to signal errors in PMU event filter test
KVM: selftests: Print detailed info in PMU event filter asserts
KVM: selftests: Add helpers for PMC asserts in PMU event filter test
KVM: selftests: Add a common helper for the PMU event filter guest code
KVM: selftests: Fix spelling mistake "perrmited" -> "permitted"
KVM: arm64: vhe: Drop extra isb() on guest exit
KVM: arm64: vhe: Synchronise with page table walker on MMU update
KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc()
KVM: arm64: nvhe: Synchronise with page table walker on TLBI
KVM: arm64: Handle 32bit CNTPCTSS traps
KVM: arm64: nvhe: Synchronise with page table walker on vcpu run
KVM: arm64: vgic: Don't acquire its_lock before config_lock
KVM: selftests: Add test to verify KVM's supported XCR0
...
