From: Paolo Bonzini <pbonzini@redhat.com>
To: Lai Jiangshan <jiangshanlai@gmail.com>,
David Matlack <dmatlack@google.com>
Cc: Sean Christopherson <seanjc@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Lai Jiangshan <jiangshan.ljs@antgroup.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>,
Dave Hansen <dave.hansen@linux.intel.com>,
X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Avi Kivity <avi@redhat.com>, kvm list <kvm@vger.kernel.org>
Subject: Re: [PATCH] kvm: x86/svm/nested: Cache PDPTEs for nested NPT in PAE paging mode
Date: Thu, 26 May 2022 11:33:20 +0200 [thread overview]
Message-ID: <70cec00b-428f-9310-96b6-c6257fe36dec@redhat.com> (raw)
In-Reply-To: <CAJhGHyBtVwZ9G+Mv8FMwC4Uku_gK4-Ng7+x+FqykZLftANm0Yg@mail.gmail.com>
On 5/26/22 10:38, Lai Jiangshan wrote:
>> (Although the APM does say that "modern processors" do not pre-load
>> PDPTEs.)
This changed between the Oct 2020 and Nov 2021, so I suppose the change
was done in Zen 3.
> Oh, I also missed the fact that L1 is the host when emulating it.
>
> The code is for host-mode (L1)'s nested_cr3 which is using the
> traditional PAE PDPTEs loading and checking.
>
> So using caches is the only correct way, right?
The caching behavior for NPT PDPTEs does not matter too much. What
matters is that a PDPTE with reserved bits should cause a #NPF at usage
time rather than a VMentry failure or a #NPF immediately after VMentry.
Paolo
next prev parent reply other threads:[~2022-05-26 9:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-15 10:34 Lai Jiangshan
2022-05-13 8:54 ` Lai Jiangshan
2022-05-16 20:45 ` Sean Christopherson
2022-05-17 1:02 ` Lai Jiangshan
2022-05-17 1:10 ` Lai Jiangshan
2022-05-25 21:45 ` David Matlack
2022-05-26 8:38 ` Lai Jiangshan
2022-05-26 9:33 ` Paolo Bonzini [this message]
2022-05-26 9:52 ` Lai Jiangshan
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=70cec00b-428f-9310-96b6-c6257fe36dec@redhat.com \
--to=pbonzini@redhat.com \
--cc=avi@redhat.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=dmatlack@google.com \
--cc=hpa@zytor.com \
--cc=jiangshan.ljs@antgroup.com \
--cc=jiangshanlai@gmail.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=mtosatti@redhat.com \
--cc=seanjc@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
all inboxes | Powered by JetHome®