From: Jim Mattson <jmattson@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Mohammed Gamal <mgamal@redhat.com>,
kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v3 7/9] KVM: VMX: Add guest physical address check in EPT violation and misconfig
Date: Fri, 23 Oct 2020 10:23:43 -0700 [thread overview]
Message-ID: <CALMp9eRGBiQDPr1wpAY34V=T6Jjij_iuHOX+_-QQPP=5SEw3GQ@mail.gmail.com> (raw)
In-Reply-To: <f40e5d23-88b6-01c0-60f9-5419dac703a2@redhat.com>
On Fri, Oct 23, 2020 at 10:16 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 23/10/20 18:59, Jim Mattson wrote:
> >> The problem is that page fault error code bits cannot be reconstructed
> >> from bits 0..2 of the EPT violation exit qualification, if bit 8 is
> >> clear in the exit qualification (that is, if the access causing the EPT
> >> violation is to a paging-structure entry). In that case bits 0..2 refer
> >> to the paging-structure access rather than to the final access. In fact
> >> advanced information is not available at all for paging-structure access
> >> EPT violations.
> >
> > True, but the in-kernel emulator can only handle a very small subset
> > of the available instructions.
> >
> > If bit 8 is set in the exit qualification, we should use the advanced
> > VM-exit information. If it's clear, we should just do a software page
> > walk of the guest's x86 page tables.
>
> The information that we need is _not_ that provided by the advanced
> VM-exit information (or by a page walk). If a page is neither writable
> nor executable, the advanced information doesn't say if the injected #PF
> should be a W=1 or a F=1 fault. We need the information in bits 0..2 of
> the exit qualification for the final access, which however is not
> available for the paging-structure access.
>
Are you planning to extend the emulator, then, to support all
instructions? I'm not sure where you are going with this.
next prev parent reply other threads:[~2020-10-23 17:24 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 15:48 [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 1/9] KVM: x86: Add helper functions for illegal GPA checking and page fault injection Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 2/9] KVM: x86: mmu: Move translate_gpa() to mmu.c Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 3/9] KVM: x86: mmu: Add guest physical address check in translate_gpa() Mohammed Gamal
2020-07-10 17:41 ` Paolo Bonzini
2020-07-10 15:48 ` [PATCH v3 4/9] KVM: x86: rename update_bp_intercept to update_exception_bitmap Mohammed Gamal
2020-07-10 16:15 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 5/9] KVM: x86: update exception bitmap on CPUID changes Mohammed Gamal
2020-07-10 16:25 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 6/9] KVM: VMX: introduce vmx_need_pf_intercept Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 7/9] KVM: VMX: Add guest physical address check in EPT violation and misconfig Mohammed Gamal
2020-07-13 18:32 ` Sean Christopherson
2020-07-15 23:00 ` Sean Christopherson
2020-08-17 17:22 ` Sean Christopherson
2020-08-17 18:01 ` Paolo Bonzini
2020-10-09 16:17 ` Jim Mattson
2020-10-14 23:44 ` Jim Mattson
2020-10-23 3:14 ` Sean Christopherson
2020-10-23 9:22 ` Paolo Bonzini
2020-10-23 16:59 ` Jim Mattson
2020-10-23 17:16 ` Paolo Bonzini
2020-10-23 17:23 ` Jim Mattson [this message]
2020-10-23 17:43 ` Paolo Bonzini
2021-01-15 19:35 ` Jim Mattson
2021-01-20 21:16 ` Jim Mattson
2021-01-27 20:57 ` Jim Mattson
2021-06-21 18:31 ` Jim Mattson
2020-07-10 15:48 ` [PATCH v3 8/9] KVM: VMX: optimize #PF injection when MAXPHYADDR does not match Mohammed Gamal
2020-07-10 15:48 ` [PATCH v3 9/9] KVM: x86: SVM: VMX: Make GUEST_MAXPHYADDR < HOST_MAXPHYADDR support configurable Mohammed Gamal
2020-07-10 17:40 ` Paolo Bonzini
2020-07-10 16:30 ` [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR Jim Mattson
2020-07-10 17:06 ` Paolo Bonzini
2020-07-10 17:13 ` Jim Mattson
2020-07-10 17:16 ` Paolo Bonzini
2020-07-10 17:26 ` Sean Christopherson
2020-07-10 17:26 ` Jim Mattson
2020-07-10 17:40 ` Paolo Bonzini
2020-07-10 17:49 ` Paolo Bonzini
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='CALMp9eRGBiQDPr1wpAY34V=T6Jjij_iuHOX+_-QQPP=5SEw3GQ@mail.gmail.com' \
--to=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mgamal@redhat.com \
--cc=pbonzini@redhat.com \
--cc=sean.j.christopherson@intel.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.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).