From: David Vrabel <david.vrabel@citrix.com>
To: Jan Beulich <JBeulich@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Keir Fraser <keir@xen.org>
Subject: Re: [PATCH] x86/xstate: undo bogus adjustment to xsave()
Date: Thu, 10 Mar 2016 12:27:37 +0000 [thread overview]
Message-ID: <56E16839.9020204@citrix.com> (raw)
In-Reply-To: <56E132B402000078000DB110@prv-mh.provo.novell.com>
On 10/03/16 07:39, Jan Beulich wrote:
> This reverts an unintended change in commit 879b44b041 ("x86/fpu: add
> a per-domain field to set the width of FIP/FDP"), which I had done
> intermediately while fixing the build issue: After having reverted that
> adjustment I must have forgotten to "git add" the adjustment.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
It think you also need to only clobber fip/fdp in memory if mask &
XSTATE_FP.
But, quite frankly, this logic too complicated and clearly too fragile
and you should just take the simplification I posted.
David
>
> --- a/xen/arch/x86/xstate.c
> +++ b/xen/arch/x86/xstate.c
> @@ -292,7 +292,7 @@ void xsave(struct vcpu *v, uint64_t mask)
>
> XSAVE("0x48,");
>
> - if ( !(ptr->xsave_hdr.xstate_bv & XSTATE_FP) ||
> + if ( !(mask & ptr->xsave_hdr.xstate_bv & XSTATE_FP) ||
> /*
> * AMD CPUs don't save/restore FDP/FIP/FOP unless an exception
> * is pending.
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>
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next prev parent reply other threads:[~2016-03-10 12:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 7:39 [PATCH] x86/xstate: undo bogus adjustment to xsave() Jan Beulich
2016-03-10 12:04 ` Andrew Cooper
2016-03-10 12:27 ` David Vrabel [this message]
2016-03-10 13:16 ` Jan Beulich
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