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Subject[PATCH 4.4 227/266] kvm: x86: Report STIBP on GET_SUPPORTED_CPUID
Date
From: Eduardo Habkost <ehabkost@redhat.com>

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 d28b387fb74d ("KVM/VMX: Allow direct access to
MSR_IA32_SPEC_CTRL") and b2ac58f90540 ("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>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/cpuid.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -344,7 +344,7 @@ static inline int __do_cpuid_ent(struct
/* 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_supported_word5_x86_features =
@@ -365,7 +365,8 @@ static inline int __do_cpuid_ent(struct

/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
- F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES);
+ F(SPEC_CTRL) | F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) |
+ F(INTEL_STIBP);

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

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