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: [V4] x86/xsaves: calculate the xstate_comp_offsets base on xstate_bv
Date: Wed, 23 Mar 2016 11:28:36 +0800 [thread overview]
Message-ID: <40809.4782186255$1458703938@news.gmane.org> (raw)
In-Reply-To: <20160323012803.GA4131@shuai.ruan@linux.intel.com>
On Wed, Mar 23, 2016 at 09:28:03AM +0800, Shuai Ruan wrote:
> On Tue, Mar 22, 2016 at 04:53:02AM -0600, Jan Beulich wrote:
> > >>> On 16.03.16 at 13:12, <shuai.ruan@linux.intel.com> wrote:
> >
> > Don't you need to use xcomp_bv here? That's what "Extended
> > Region of an XSAVE Area" in SDM Vol 1 suggests to me.
> >
> "OPERATION OF XRSTORS" and "OPERATION OF XSAVES" in SDM Vol1.
>
> For xsaves:
> "Execution of XSAVES performs the init optimization to reduce the amount
> of data written to memory."
>
> For xrstors:
> "XRSTORS updates state component i based on the value of bit i in the
> XSTATE_BV field of the XSAVE header".
>
Ignore this. You are right.
I misunderstand some XSAVES/XRSTORS behaviors in SDM . In the previous versions,
I use xcom_bv to caculate comp_offset (but changing to xstate_bv in this
version:( ).
Thanks.
> > > /* Set XSTATE_BV and XCOMP_BV. */
> > > xsave->xsave_hdr.xstate_bv = xstate_bv;
> > > xsave->xsave_hdr.xcomp_bv = v->arch.xcr0_accum | XSTATE_COMPACTION_ENABLED;
> > > + setup_xstate_comp(xstate_comp_offsets, xstate_bv);
> >
> > Same here then I think.
> >
> > Jan
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
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prev parent reply other threads:[~2016-03-23 3:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 12:12 [V4] x86/xsaves: calculate the xstate_comp_offsets base on xstate_bv Shuai Ruan
2016-03-22 10:53 ` Jan Beulich
2016-03-23 1:28 ` Shuai Ruan
[not found] ` <20160323012803.GA4131@shuai.ruan@linux.intel.com>
2016-03-23 3:28 ` Shuai Ruan [this message]
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