Commit ca0056d9 authored Dec 05, 2018 by Eduardo Habkost Committed by Greg Kroah-Hartman May 14, 2019

kvm: x86: Report STIBP on GET_SUPPORTED_CPUID



commit d7b09c827a6cf291f66637a36f46928dd1423184 upstream

Months ago, we have added code to allow direct access to MSR_IA32_SPEC_CTRL
to the guest, which makes STIBP available to guests.  This was implemented
by commits d28b387f ("KVM/VMX: Allow direct access to
MSR_IA32_SPEC_CTRL") and b2ac58f9 ("KVM/SVM: Allow direct access to
MSR_IA32_SPEC_CTRL").

However, we never updated GET_SUPPORTED_CPUID to let userspace know that
STIBP can be enabled in CPUID.  Fix that by updating
kvm_cpuid_8000_0008_ebx_x86_features and kvm_cpuid_7_0_edx_x86_features.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1f1bc822

arch/x86/kvm/cpuid.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -382,7 +382,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
		/* cpuid 0x80000008.ebx */
		const u32 kvm_cpuid_8000_0008_ebx_x86_features =
		F(AMD_IBPB) \| F(AMD_IBRS) \| F(AMD_SSBD) \| F(VIRT_SSBD) \|
		F(AMD_SSB_NO);
		F(AMD_SSB_NO) \| F(AMD_STIBP);

		/* cpuid 0xC0000001.edx */
		const u32 kvm_cpuid_C000_0001_edx_x86_features =
		@@ -412,7 +412,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
		/* cpuid 7.0.edx*/
		const u32 kvm_cpuid_7_0_edx_x86_features =
		F(AVX512_4VNNIW) \| F(AVX512_4FMAPS) \| F(SPEC_CTRL) \|
		F(SPEC_CTRL_SSBD) \| F(ARCH_CAPABILITIES);
		F(SPEC_CTRL_SSBD) \| F(ARCH_CAPABILITIES) \| F(INTEL_STIBP);

		/* all calls to cpuid_count() should be made on the same cpu */
		get_cpu();