From 5d5103595e9e53048bb7e70ee2673c897ab38300 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 8 Jun 2020 10:41:34 -0700 Subject: 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 Signed-off-by: Sean Christopherson Signed-off-by: Borislav Petkov Reviewed-by: Liam Merwick Reviewed-by: Maxim Levitsky Tested-by: Brad Campbell Cc: stable@vger.kernel.org # v5.6 Link: https://lkml.kernel.org/r/20200608174134.11157-1-sean.j.christopherson@intel.com --- arch/x86/power/cpu.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/power') 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 */ -- cgit v1.2.3