From: Paolo Bonzini <pbonzini@redhat.com>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: stable@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>
Subject: Re: [PATCH 1/2] KVM: MMU: fix ept=0/pte.u=0/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo
Date: Thu, 10 Mar 2016 11:03:07 +0100 [thread overview]
Message-ID: <56E1465B.3030507@redhat.com> (raw)
In-Reply-To: <56E13454.3080604@linux.intel.com>
On 10/03/2016 09:46, Xiao Guangrong wrote:
>
>> Yes, all of these are needed. :) This is admittedly a bit odd, but
>> kvm-unit-tests access.flat tests this if you run it with "-cpu host"
>> and of course ept=0.
>>
>> KVM handles supervisor writes of a pte.u=0/pte.w=0/CR0.WP=0 page by
>> setting U=0 and W=1 in the shadow PTE. This will cause a user write
>> to fault and a supervisor write to succeed (which is correct because
>> CR0.WP=0). A user read instead will flip U=0 to 1 and W=1 back to 0.
>
> BTW, it should be pte.u = 1 where you mentioned above.
Ok, will fix.
Paolo
next prev parent reply other threads:[~2016-03-10 10:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 11:44 [PATCH 0/2] KVM: MMU: fix ept=0/pte.u=0/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 Paolo Bonzini
2016-03-08 11:44 ` [PATCH 1/2] KVM: MMU: fix ept=0/pte.u=0/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo Paolo Bonzini
2016-03-10 8:27 ` Xiao Guangrong
2016-03-10 10:01 ` Paolo Bonzini
2016-03-10 10:09 ` Paolo Bonzini
2016-03-10 12:14 ` Xiao Guangrong
2016-03-10 12:26 ` Paolo Bonzini
2016-03-10 8:46 ` Xiao Guangrong
2016-03-10 10:03 ` Paolo Bonzini [this message]
2016-03-08 11:44 ` [PATCH 2/2] KVM: MMU: fix reserved bit check for pte.u=0/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 Paolo Bonzini
2016-03-10 8:36 ` Xiao Guangrong
2016-03-10 10:02 ` Paolo Bonzini
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=56E1465B.3030507@redhat.com \
--to=pbonzini@redhat.com \
--cc=guangrong.xiao@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=stable@vger.kernel.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).