From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 3/3] KVM: remove dummy pages
Date: Thu, 26 Jul 2012 17:35:13 +0800 [thread overview]
Message-ID: <50110F51.3050903@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120726182033.e127e9e6.yoshikawa.takuya@oss.ntt.co.jp>
On 07/26/2012 05:20 PM, Takuya Yoshikawa wrote:
> On Thu, 26 Jul 2012 11:56:15 +0300
> Avi Kivity <avi@redhat.com> wrote:
>
>> Since my comments are better done as a separate patch, I applied all
>> three patches. Thanks!
>
> Is this patch really safe for all architectures?
>
> IS_ERR_VALUE() casts -MAX_ERRNO to unsigned long and then does comparison.
> Isn't it possible to conflict with valid pfns?
>
See IS_ERR_VALUE():
#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
The minimal value of the error code is:
0xffff f001 on 32-bit and 0x ffff ffff ffff f001 on 64-bit,
it is fair larger that a valid pfn (for the pfn, the most top of 12 bits
are always 0).
Note, PAE is a special case, but only 64G physical memory is valid,
0xffff f001 is also suitable for that.
next prev parent reply other threads:[~2012-07-26 9:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-26 3:56 [PATCH v2 0/3] KVM: remove dummy pages Xiao Guangrong
2012-07-26 3:57 ` [PATCH v2 1/3] KVM: MMU: use kvm_release_pfn_clean to release pfn Xiao Guangrong
2012-07-26 3:58 ` [PATCH v2 2/3] KVM: use kvm_release_page_clean to release the page Xiao Guangrong
2012-07-26 3:58 ` [PATCH v2 3/3] KVM: remove dummy pages Xiao Guangrong
2012-07-26 8:56 ` Avi Kivity
2012-07-26 9:20 ` Takuya Yoshikawa
2012-07-26 9:35 ` Xiao Guangrong [this message]
2012-07-26 9:52 ` Takuya Yoshikawa
2012-07-26 9:25 ` Xiao Guangrong
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=50110F51.3050903@linux.vnet.ibm.com \
--to=xiaoguangrong@linux.vnet.ibm.com \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=yoshikawa.takuya@oss.ntt.co.jp \
/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.