Re: [PATCH AUTOSEL 5.3 28/68] KVM: x86: Expose XSAVEERPTR to the guest

On 2019-10-09 23:15:07 [+0200], Paolo Bonzini wrote:

...

--- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -479,6 +479,7 @@ 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(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);

Yet another example of a patch that shouldn't be stable material (in this case it's fine, but there can certainly be cases where just adding a single flag depends on core kernel changes).

Also, taking advantage of this feature requires changes which just landed in qemu's master branch.

Paolo

Sebastian