From: "Jan Beulich" <JBeulich@suse.com>
To: Shuai Ruan <shuai.ruan@linux.intel.com>
Cc: andrew.cooper3@citrix.com, keir@xen.org, xen-devel@lists.xen.org
Subject: Re: [PATCH V6 1/2] x86/xsaves: calculate the comp_offsets base on xcomp_bv
Date: Tue, 29 Mar 2016 08:35:34 -0600 [thread overview]
Message-ID: <56FAAED602000078000E0EF2@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1458808173-23279-2-git-send-email-shuai.ruan@linux.intel.com>
>>> On 24.03.16 at 09:29, <shuai.ruan@linux.intel.com> wrote:
> static void *get_xsave_addr(struct xsave_struct *xsave,
> - unsigned int xfeature_idx)
> + const uint16_t *comp_offsets,
> + unsigned int xfeature_idx)
> {
> if ( !((1ul << xfeature_idx) & xsave->xsave_hdr.xstate_bv) )
> return NULL;
While not a problem in this patch, I think this being at least
questionable now becomes more obvious: With XSAVEC and
XSAVES this field may have clear bits just because the
component was in init state. Yet I don't think this should be
fixed here - instead the consumer(s) should better deal with
NULL coming back here (i.e. expand_xsave_states() should
probably memset() the area in an "else" to the if() leading to
memcpy(), whereas compress_xsave_states() is fine as is).
That's a 3rd patch, though.
> + return (void *)xsave + (xsave_area_compressed(xsave) ?
> + comp_offsets[xfeature_idx] :
> + xstate_offsets[xfeature_idx]);
This function doesn't ever get called when
!xsave_area_compressed(xsave), so I don't really see why this
conditional expression ever got added. Yet another follow-up
patch I would say.
The patch here looks okay to me now.
Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-29 14:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 8:29 [PATCH V6 0/2] xsaves bug fix Shuai Ruan
2016-03-24 8:29 ` [PATCH V6 1/2] x86/xsaves: calculate the comp_offsets base on xcomp_bv Shuai Ruan
2016-03-29 14:35 ` Jan Beulich [this message]
2016-03-30 5:48 ` Shuai Ruan
2016-03-24 8:29 ` [PATCH V6 2/2] x86/xsaves: fix overwriting between non-lazy/lazy xsaves Shuai Ruan
2016-03-29 15:00 ` Jan Beulich
2016-03-30 5:46 ` Shuai Ruan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56FAAED602000078000E0EF2@prv-mh.provo.novell.com \
--to=jbeulich@suse.com \
--cc=andrew.cooper3@citrix.com \
--cc=keir@xen.org \
--cc=shuai.ruan@linux.intel.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).