This is a note to let you know that I've just added the patch titled
KVM: x86: do not save guest-unsupported XSAVE state
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-do-not-save-guest-unsupported-xsave-state.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 00c87e9a70a17b355b81c36adedf05e84f54e10d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@xxxxxxxxxx>
Date: Wed, 1 Feb 2017 14:19:53 +0100
Subject: KVM: x86: do not save guest-unsupported XSAVE state
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From: Radim Krčmář <rkrcmar@xxxxxxxxxx>
commit 00c87e9a70a17b355b81c36adedf05e84f54e10d upstream.
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")
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3057,6 +3057,7 @@ static void fill_xsave(u8 *dest, struct
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;
/*
Patches currently in stable-queue which might be from rkrcmar@xxxxxxxxxx are
queue-4.4/kvm-x86-do-not-save-guest-unsupported-xsave-state.patch
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