From: Andi Kleen <andi@firstfloor.org>
To: Avi Kivity <avi.kivity@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
peterz@infradead.org, gleb@kernel.org, pbonzini@redhat.com,
eranian@google.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 4/4] kvm: Implement PEBS virtualization
Date: Sun, 22 Jun 2014 21:02:25 +0200 [thread overview]
Message-ID: <20140622190225.GN5714@two.firstfloor.org> (raw)
In-Reply-To: <53A6E0B9.10408@gmail.com>
> First, it's not sufficient to pin the debug store area, you also
> have to pin the guest page tables that are used to map the debug
> store. But even if you do that, as soon as the guest fork()s, it
> will create a new pgd which the host will be free to swap out. The
> processor can then attempt a PEBS store to an unmapped address which
> will fail, even though the guest is configured correctly.
That's a good point. You're right of course.
The only way I can think around it would be to intercept CR3 writes
while PEBS is active and always pin all the table pages leading
to the PEBS buffer. That's slow, but should be only needed
while PEBS is running.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2014-06-22 19:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 1:12 Implement PEBS virtualization for Silvermont Andi Kleen
2014-05-30 1:12 ` [PATCH 1/4] perf: Add PEBS virtualization enable " Andi Kleen
2014-05-30 1:12 ` [PATCH 2/4] perf: Allow guest PEBS for KVM owned counters Andi Kleen
2014-05-30 7:31 ` Peter Zijlstra
2014-05-30 16:03 ` Andi Kleen
2014-05-30 16:17 ` Peter Zijlstra
2014-05-30 1:12 ` [PATCH 3/4] perf: Handle guest PEBS events with a fake event Andi Kleen
2014-05-30 7:34 ` Peter Zijlstra
2014-05-30 16:29 ` Andi Kleen
2014-05-30 1:12 ` [PATCH 4/4] kvm: Implement PEBS virtualization Andi Kleen
2014-05-30 8:21 ` Gleb Natapov
2014-05-30 16:24 ` Andi Kleen
2014-06-02 16:45 ` Gleb Natapov
2014-06-02 16:52 ` Andi Kleen
2014-06-02 19:09 ` Marcelo Tosatti
2014-06-02 19:05 ` Eric Northup
2014-06-02 19:57 ` Andi Kleen
2014-06-19 14:39 ` Paolo Bonzini
2014-06-10 18:04 ` Marcelo Tosatti
2014-06-10 19:22 ` Andi Kleen
2014-06-10 21:06 ` Marcelo Tosatti
2014-06-19 14:42 ` Paolo Bonzini
2014-06-19 17:33 ` Andi Kleen
2014-06-19 20:33 ` Paolo Bonzini
2014-06-22 13:57 ` Avi Kivity
2014-06-22 19:02 ` Andi Kleen [this message]
2014-06-24 16:45 ` Marcelo Tosatti
2014-06-25 7:04 ` Avi Kivity
2014-05-30 7:39 ` Implement PEBS virtualization for Silvermont Peter Zijlstra
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=20140622190225.GN5714@two.firstfloor.org \
--to=andi@firstfloor.org \
--cc=ak@linux.intel.com \
--cc=avi.kivity@gmail.com \
--cc=eranian@google.com \
--cc=gleb@kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.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