From: Shuai Ruan <shuai.ruan@linux.intel.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: andrew.cooper3@citrix.com, keir@xen.org, xen-devel@lists.xen.org
Subject: Re: [V3] x86/xsaves: fix overwriting between non-lazy/lazy xsaves
Date: Wed, 9 Mar 2016 20:33:22 +0800 [thread overview]
Message-ID: <27126.8865828917$1457527056@news.gmane.org> (raw)
In-Reply-To: <56DFFA3602000078000E42D4@prv-mh.provo.novell.com>
On Wed, Mar 09, 2016 at 03:25:58AM -0700, Jan Beulich wrote:
> Btw., one more thing: Can't the exclusion of FP and SSE states in the logic
> determining which state set to save be extended to also include YMM? If saved,
> YMM will also always live at a fixed place (an ASSERT() or BUG_ON() to verify
> would of course be desirable). And if the guest didn't touch YMM registers, the
> respective bit in the mask won't be set anyway.
>
YMM do live at the begining of the xsave extended area. But when we
exclude YMM like FP/SSE states ,if guest set YMM | XSTATE_NONLAZY respective bitin xcro_accum, the over-writing may happend too. In such case , vcpu_xsave_mask
will return XSTATE_NONLAZY, the first xstate of XSTATE_NONLAZY will be
xsaved at the begining of xsave extended area which may over-write YMM
state.
Do I miss something ?
> Jan
>
>
> _______________________________________________
> 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:[~2016-03-09 12:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 7:19 [V3] x86/xsaves: fix overwriting between non-lazy/lazy xsaves Shuai Ruan
2016-03-08 10:16 ` Jan Beulich
2016-03-09 9:46 ` Shuai Ruan
[not found] ` <20160309094650.GA23774@shuai.ruan@linux.intel.com>
2016-03-09 10:25 ` Jan Beulich
2016-03-09 12:33 ` Shuai Ruan [this message]
[not found] ` <20160309123322.GA16645@shuai.ruan@linux.intel.com>
2016-03-09 13:41 ` Jan Beulich
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