All of lore.kernel.org
 help / color / mirror / Atom feed
From: Shuai Ruan <shuai.ruan@linux.intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: andrew.cooper3@citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH V7 1/3] x86/xsaves: fix overwriting between non-lazy/lazy xsaves
Date: Fri, 29 Apr 2016 09:36:16 +0800	[thread overview]
Message-ID: <35810.9452100054$1461893710@news.gmane.org> (raw)
In-Reply-To: <571DDAA002000078000E51A7@prv-mh.provo.novell.com>

On Mon, Apr 25, 2016 at 12:51:44AM -0600, Jan Beulich wrote:
> >>> On 31.03.16 at 10:57, <shuai.ruan@linux.intel.com> wrote:
> > +#define XRSTOR(pfx) \
> > +        if ( v->arch.xcr0_accum & XSTATE_XSAVES_ONLY ) \
> > +        { \
> > +            if ( unlikely(!(ptr->xsave_hdr.xcomp_bv & \
> > +                            XSTATE_COMPACTION_ENABLED)) ) \
> > +                ptr->xsave_hdr.xcomp_bv |= ptr->xsave_hdr.xstate_bv | \
> > +                                           XSTATE_COMPACTION_ENABLED; \
> 
> From v5 to v6 this changed from just = to |=, without any
> explanation, and without me really noticing - why? Weren't
> the other changes done specifically to guarantee xcomp_bv
> to be zero up to this point? In which case I'd prefer to make
> this obvious/explicit, by using = and perhaps an ASSERT()
> here. (I have a patch ready, but I'd like to understand if
> there was a reason for this change that I don't see.)
> 
> Jan
Using "=" is better. xcomp_bv can be guarantee to be zero to this
point.

Thanks

> 
> 
> _______________________________________________
> 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

  reply	other threads:[~2016-04-29  1:36 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-31  8:57 [PATCH V7 0/3] xsaves bug fix Shuai Ruan
2016-03-31  8:57 ` [PATCH V7 1/3] x86/xsaves: fix overwriting between non-lazy/lazy xsaves Shuai Ruan
2016-04-04 15:51   ` Jan Beulich
2016-04-05  5:30     ` Shuai Ruan
     [not found]     ` <20160405053023.GA16876@shuai.ruan@linux.intel.com>
2016-04-05  7:17       ` Jan Beulich
2016-04-05  7:29         ` Shuai Ruan
2016-04-25  6:51   ` Jan Beulich
2016-04-29  1:36     ` Shuai Ruan [this message]
     [not found]     ` <20160429013616.GB4359@shuai.ruan@linux.intel.com>
2016-04-29  7:05       ` Jan Beulich
2016-03-31  8:57 ` [PATCH V7 2/3] x86/xsaves: fix two remained issues Shuai Ruan
2016-04-04 16:03   ` Jan Beulich
2016-03-31  8:57 ` [PATCH V7 3/3] x86/xsaves: ebx may return wrong value using CPUID eax=0xdh, ecx =1 Shuai Ruan
2016-04-05  8:31   ` Jan Beulich
2016-04-06  7:01     ` Shuai Ruan
     [not found]     ` <20160406070034.GA26357@shuai.ruan@linux.intel.com>
2016-04-07  0:29       ` Jan Beulich

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='35810.9452100054$1461893710@news.gmane.org' \
    --to=shuai.ruan@linux.intel.com \
    --cc=JBeulich@suse.com \
    --cc=andrew.cooper3@citrix.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.