From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: "Yang, Wei Y" <wei.y.yang@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [Patch v4 2/4] Add SMEP handling when setting CR4
Date: Tue, 31 May 2011 22:03:26 +0300 [thread overview]
Message-ID: <4DE53B7E.4070403@redhat.com> (raw)
In-Reply-To: <20110531184827.GA4376@amt.cnet>
On 05/31/2011 09:48 PM, Marcelo Tosatti wrote:
> On Tue, May 31, 2011 at 09:05:35PM +0300, Avi Kivity wrote:
> > >> if (is_long_mode(vcpu)) {
> > >> if (!(cr4& X86_CR4_PAE))
> > >> return 1;
> > >
> > >A new field in vcpu->arch.mmu.base_role for smep is required
> > >for shadow MMU (similar to nxe).
> >
> > I plan to add that with my cr0.wp=0 fixup (it's only needed there, right?)
>
> Sptes instantiated when cr4.smep = 0 should not be used when cr4.smep =
> 1, so no (unlikely that guest kernel executes user=1 code anyway, but
> for consistency with other base_role flags).
Why not? The sptes are interpreted exactly the same.
sptes are interpreted differently when efer.nxe=1 - if bit 63 is set, it
will fault when nxe=0 and will not fault when nxe=1 (for non-fetch
accesses). So we can't share those sptes.
> OK then, you'll fix that.
>
Sure. I'll post the patches as soon as this hits 'next'.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2011-05-31 19:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-29 11:41 [Patch v4 2/4] Add SMEP handling when setting CR4 Yang, Wei Y
2011-05-31 17:52 ` Marcelo Tosatti
2011-05-31 18:05 ` Avi Kivity
2011-05-31 18:48 ` Marcelo Tosatti
2011-05-31 19:03 ` Avi Kivity [this message]
2011-06-01 12:32 ` Marcelo Tosatti
2011-06-01 12:36 ` Avi Kivity
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=4DE53B7E.4070403@redhat.com \
--to=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=wei.y.yang@intel.com \
/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.