From: David Matlack <dmatlack@google.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>,
Ben Gardon <bgardon@google.com>
Subject: Re: [PATCH] KVM: x86: Preserve TDP MMU roots until they are explicitly invalidated
Date: Thu, 20 Apr 2023 13:34:51 -0700 [thread overview]
Message-ID: <ZEGh6zrhJX/SN9jp@google.com> (raw)
In-Reply-To: <20230413231251.1481410-1-seanjc@google.com>
On Thu, Apr 13, 2023 at 04:12:51PM -0700, Sean Christopherson wrote:
> Preserve TDP MMU roots until they are explicitly invalidated by gifting
> the TDP MMU itself a reference to a root when it is allocated. Keeping a
> reference in the TDP MMU fixes a flaw where the TDP MMU exhibits terrible
> performance, and can potentially even soft-hang a vCPU, if a vCPU
> frequently unloads its roots, e.g. when KVM is emulating SMI+RSM.
>
[...]
>
> Reported-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
> Link: https://lore.kernel.org/all/959c5bce-beb5-b463-7158-33fc4a4f910c@linux.microsoft.com
> Link: https://lkml.kernel.org/r/20220209170020.1775368-1-pbonzini%40redhat.com
> Link: https://lore.kernel.org/all/20230322013731.102955-1-minipli@grsecurity.net
> Cc: David Matlack <dmatlack@google.com>
> Cc: Ben Gardon <bgardon@google.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
next prev parent reply other threads:[~2023-04-20 20:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-13 23:12 [PATCH] KVM: x86: Preserve TDP MMU roots until they are explicitly invalidated Sean Christopherson
2023-04-14 11:58 ` Jeremi Piotrowski
2023-04-14 16:55 ` Sean Christopherson
2023-04-20 20:34 ` David Matlack [this message]
2023-04-20 23:05 ` Sean Christopherson
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=ZEGh6zrhJX/SN9jp@google.com \
--to=dmatlack@google.com \
--cc=bgardon@google.com \
--cc=jpiotrowski@linux.microsoft.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.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