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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-06-08 10:41:34 -0700 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-06-15 14:18:37 +0200 |
| commit | 5d5103595e9e53048bb7e70ee2673c897ab38300 (patch) | |
| tree | 733c865296305bee65d1f418f2a4816ead780237 /arch/x86/power | |
| parent | 8e742aa79780b13cd300a42198c1a4cea9c89905 (diff) | |
| download | lwn-5d5103595e9e53048bb7e70ee2673c897ab38300.tar.gz lwn-5d5103595e9e53048bb7e70ee2673c897ab38300.zip | |
x86/cpu: Reinitialize IA32_FEAT_CTL MSR on BSP during wakeup
Reinitialize IA32_FEAT_CTL on the BSP during wakeup to handle the case
where firmware doesn't initialize or save/restore across S3. This fixes
a bug where IA32_FEAT_CTL is left uninitialized and results in VMXON
taking a #GP due to VMX not being fully enabled, i.e. breaks KVM.
Use init_ia32_feat_ctl() to "restore" IA32_FEAT_CTL as it already deals
with the case where the MSR is locked, and because APs already redo
init_ia32_feat_ctl() during suspend by virtue of the SMP boot flow being
used to reinitialize APs upon wakeup. Do the call in the early wakeup
flow to avoid dependencies in the syscore_ops chain, e.g. simply adding
a resume hook is not guaranteed to work, as KVM does VMXON in its own
resume hook, kvm_resume(), when KVM has active guests.
Fixes: 21bd3467a58e ("KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR")
Reported-by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Brad Campbell <lists2009@fnarfbargle.com>
Cc: stable@vger.kernel.org # v5.6
Link: https://lkml.kernel.org/r/20200608174134.11157-1-sean.j.christopherson@intel.com
Diffstat (limited to 'arch/x86/power')
| -rw-r--r-- | arch/x86/power/cpu.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 7c65102debaf..db1378c6ff26 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -193,6 +193,8 @@ static void fix_processor_context(void) */ static void notrace __restore_processor_state(struct saved_context *ctxt) { + struct cpuinfo_x86 *c; + if (ctxt->misc_enable_saved) wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable); /* @@ -263,6 +265,10 @@ static void notrace __restore_processor_state(struct saved_context *ctxt) mtrr_bp_restore(); perf_restore_debug_store(); msr_restore_context(ctxt); + + c = &cpu_data(smp_processor_id()); + if (cpu_has(c, X86_FEATURE_MSR_IA32_FEAT_CTL)) + init_ia32_feat_ctl(c); } /* Needed by apm.c */ |