Re: [PATCH v4 18/21] kvm: x86: Add support for getting/setting expanded xstate buffer

On Wed, Dec 29, 2021, Yang Zhong wrote:

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bdf89c28d2ce..76e1941db223 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4296,6 +4296,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) else r = 0; break;

• case KVM_CAP_XSAVE2:

• r = kvm->vcpus[0]->arch.guest_fpu.uabi_size;
  

a) This does not compile against kvm/queue.

arch/x86/kvm/x86.c: In function ‘kvm_vm_ioctl_check_extension’: arch/x86/kvm/x86.c:4317:24: error: ‘struct kvm’ has no member named ‘vcpus’ 4317 | r = kvm->vcpus[0]->arch.guest_fpu.uabi_size;

b) vcpu0 is not guaranteed to be non-NULL at this point.

• if (r < sizeof(struct kvm_xsave))
  

• 	r = sizeof(struct kvm_xsave);
  

• break;
  

  default: break; }