linux-kernel - Re: [PATCH] KVM: x86: do not save guest-unsupported XSAVE state

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Message-ID: <20170204162616.GB5582@potion>
Date:   Sat, 4 Feb 2017 17:26:17 +0100
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        stable <stable@...r.kernel.org>
Subject: Re: [PATCH] KVM: x86: do not save guest-unsupported XSAVE state

2017-02-01 16:13-0800, Paolo Bonzini:
> 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@...hat.com>
> 
> Cc: stable@...r.kernel.org
> Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
> 
> Please apply to kvm/master and send it yourself to Linus since I don't
> have access to my machine this week.

Done, thanks.