On 01/02/2017 05:19, Radim Krčmář wrote:
> Saving unsupported state prevents migration when the new host does not
> support a XSAVE feature of the original host, even if the feature is not
> exposed to the guest.
>
> We've masked host features with guest-visible features before, with
> 4344ee981e21 ("KVM: x86: only copy XSAVE state for the supported
> features") and dropped it when implementing XSAVES. Do it again.
>
> Fixes: df1daba7d1cb ("KVM: x86: support XSAVES usage in the host")
> Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Please apply to kvm/master and send it yourself to Linus since I don't
have access to my machine this week.
Paolo
> ---
> arch/x86/kvm/x86.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 96dd7dd13ee6..5f013ad89b57 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3221,6 +3221,7 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
> memcpy(dest, xsave, XSAVE_HDR_OFFSET);
>
> /* Set XSTATE_BV */
> + xstate_bv &= vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FPSSE;
> *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv;
>
> /*
>
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