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authorSean Christopherson <sean.j.christopherson@intel.com>2020-06-08 10:41:34 -0700
committerBorislav Petkov <bp@suse.de>2020-06-15 14:18:37 +0200
commit5d5103595e9e53048bb7e70ee2673c897ab38300 (patch)
tree733c865296305bee65d1f418f2a4816ead780237 /arch/x86/include
parent8e742aa79780b13cd300a42198c1a4cea9c89905 (diff)
downloadlinux-5d5103595e9e53048bb7e70ee2673c897ab38300.tar.gz
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/include')
-rw-r--r--arch/x86/include/asm/cpu.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index dd17c2da1af5..da78ccbd493b 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -58,4 +58,9 @@ static inline bool handle_guest_split_lock(unsigned long ip)
return false;
}
#endif
+#ifdef CONFIG_IA32_FEAT_CTL
+void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
+#else
+static inline void init_ia32_feat_ctl(struct cpuinfo_x86 *c) {}
+#endif
#endif /* _ASM_X86_CPU_H */