From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Peter Feiner <pfeiner@google.com>
Cc: Jon Cargille <jcargill@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kvm: x86 mmu: avoid mmu_page_hash lookup for direct_map-only VM
Date: Tue, 23 Jun 2020 08:59:18 -0700 [thread overview]
Message-ID: <20200623155918.GC23842@linux.intel.com> (raw)
In-Reply-To: <20200623065348.GA23054@linux.intel.com>
On Mon, Jun 22, 2020 at 11:53:48PM -0700, Sean Christopherson wrote:
> If we do get agressive and zap all children (or if my analysis is wrong),
> and prevent the mixed level insansity, then a simpler approach would be to
> skip the lookup if the MMU is direct. I.e. no need for the per-VM toggle.
> Direct vs. indirect MMUs are guaranteed to have different roles and so the
> direct MMU's pages can't be reused/shared.
Clarification on the above. Direct and not-guaranteed-to-be-direct MMUs for
a given VM are guaranteed to have different roles, even for nested NPT vs.
NPT, as nested MMUs will have role.guest_mode=1.
prev parent reply other threads:[~2020-06-23 15:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 18:24 [PATCH] kvm: x86 mmu: avoid mmu_page_hash lookup for direct_map-only VM Jon Cargille
2020-05-08 20:13 ` Sean Christopherson
2020-05-12 22:36 ` Peter Feiner
2020-06-23 6:53 ` Sean Christopherson
2020-06-23 15:59 ` Sean Christopherson [this message]
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=20200623155918.GC23842@linux.intel.com \
--to=sean.j.christopherson@intel.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=jcargill@google.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=pfeiner@google.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@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).