kvm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Gleb Natapov <gleb@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
	Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 6/6] KVM: introduce readonly memslot
Date: Tue, 19 Jun 2012 10:20:30 +0300	[thread overview]
Message-ID: <20120619072030.GM6533@redhat.com> (raw)
In-Reply-To: <20120618202505.GA3650@amt.cnet>

On Mon, Jun 18, 2012 at 05:25:05PM -0300, Marcelo Tosatti wrote:
> On Mon, Jun 18, 2012 at 12:50:10PM +0300, Avi Kivity wrote:
> > On 06/16/2012 05:11 AM, Marcelo Tosatti wrote:
> > > 
> > > Can you introduce a separate exit reason, say KVM_EXIT_READ_FAULT, with
> > > information about the fault?
> > 
> > I think you mean WRITE_FAULT.  
> 
> Yes.
> 
> > But what's wrong with the normal mmio exit?
> 
> It is necessary to perform an address->mmio region lookup, to verify
> whether the mmio exit is due to an actual mmio (no memory slot) or from
> a write access to a write protected slot. That information is readily
> available in the kernel but is lost if the mmio exit is used to transmit 
> the information.
> 
Why is it necessary though? Write access to a write protected slot is
MMIO by (our) definition.

> Moreover, i'd argue the uses are different: one is an mmio emulation
> exit, the other is more like handling a pagefault in qemu.
> 
What do you mean by "handling a pagefault in qemu"?

--
			Gleb.

  reply	other threads:[~2012-06-19  7:20 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-12  2:47 [PATCH v3 1/6] KVM: fix missing check for memslot flags Xiao Guangrong
2012-06-12  2:47 ` [PATCH v3 2/6] KVM: hide KVM_MEMSLOT_INVALID from userspace Xiao Guangrong
2012-06-12  2:47 ` [PATCH v3 3/6] KVM: introduce gfn_to_pfn_memslot_atomic Xiao Guangrong
2012-06-12  2:48 ` [PATCH v3 4/6] KVM: pass slot to hva_to_pfn Xiao Guangrong
2012-06-18 10:15   ` Avi Kivity
2012-06-19  2:17     ` Xiao Guangrong
2012-06-12  2:48 ` [PATCH v3 5/6] KVM: introduce gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic Xiao Guangrong
2012-06-18 10:16   ` Avi Kivity
2012-06-19  2:24     ` Xiao Guangrong
2012-06-12  2:49 ` [PATCH v3 6/6] KVM: introduce readonly memslot Xiao Guangrong
2012-06-16  2:11   ` Marcelo Tosatti
2012-06-18  3:11     ` Xiao Guangrong
2012-06-18  9:50     ` Avi Kivity
2012-06-18 20:25       ` Marcelo Tosatti
2012-06-19  7:20         ` Gleb Natapov [this message]
2012-06-19  8:11         ` Avi Kivity
2012-06-18 10:11   ` Avi Kivity
2012-06-19  2:14     ` 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=20120619072030.GM6533@redhat.com \
    --to=gleb@redhat.com \
    --cc=avi@redhat.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mtosatti@redhat.com \
    --cc=xiaoguangrong@linux.vnet.ibm.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 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).