Commit 504ce195 authored Sep 25, 2019 by Sebastian Andrzej Siewior Committed by Paolo Bonzini Sep 26, 2019

KVM: x86: Expose XSAVEERPTR to the guest



I was surprised to see that the guest reported `fxsave_leak' while the
host did not. After digging deeper I noticed that the bits are simply
masked out during enumeration.

The XSAVEERPTR feature is actually a bug fix on AMD which means the
kernel can disable a workaround.

Pass XSAVEERPTR to the guest if available on the host.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 40bc47b0

arch/x86/kvm/cpuid.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -485,9 +485,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,

		/* cpuid 0x80000008.ebx */
		const u32 kvm_cpuid_8000_0008_ebx_x86_features =
		F(CLZERO) \| F(WBNOINVD) \| F(AMD_IBPB) \| F(AMD_IBRS) \|
		F(AMD_STIBP) \| F(AMD_STIBP_ALWAYS_ON) \| F(AMD_SSBD) \|
		F(VIRT_SSBD) \| F(AMD_SSB_NO);
		F(CLZERO) \| F(XSAVEERPTR) \|
		F(WBNOINVD) \| F(AMD_IBPB) \| F(AMD_IBRS) \| F(AMD_SSBD) \| F(VIRT_SSBD) \|
		F(AMD_SSB_NO) \| F(AMD_STIBP) \| F(AMD_STIBP_ALWAYS_ON);

		/* cpuid 0xC0000001.edx */
		const u32 kvm_cpuid_C000_0001_edx_x86_features =

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