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

On 09/10/19 23:40, Sebastian Andrzej Siewior wrote:

...

...

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.

That's not a big deal, every QEMU supports every kernel and vice versa.

Paolo