@@ -4866,12 +4866,26 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
static void kvm_vcpu_ioctl_x86_get_xsave2(struct kvm_vcpu *vcpu,
u8 *state, unsigned int size)
{
+ /*
+ * Only copy state for features that are enabled for the guest. The
+ * state itself isn't problematic, but setting bits in the header for
+ * features that are supported in *this* host but not exposed to the
+ * guest can result in KVM_SET_XSAVE failing when live migrating to a
+ * compatible host without the features that are NOT exposed to the
+ * guest.
+ *
+ * FP+SSE can always be saved/restored via KVM_{G,S}ET_XSAVE, even if
+ * XSAVE/XCRO are not exposed to the guest, and even if XSAVE isn't
+ * supported by the host.
+ */
+ u64 supported_xcr0 = vcpu->arch.guest_supported_xcr0 |
+ XFEATURE_MASK_FPSSE;
+
if (fpstate_is_confidential(&vcpu->arch.guest_fpu))
return;
fpu_copy_guest_fpstate_to_uabi(&vcpu->arch.guest_fpu, state, size,
- vcpu->arch.guest_fpu.fpstate->user_xfeatures,
- vcpu->arch.pkru);
+ supported_xcr0, vcpu->arch.pkru);
}
static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,