All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jim Mattson <jmattson@google.com>
To: Mohammed Gamal <mgamal@redhat.com>
Cc: kvm list <kvm@vger.kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR
Date: Fri, 10 Jul 2020 09:30:55 -0700	[thread overview]
Message-ID: <CALMp9eRfZ50iyrED0-LU75VWhHu_kVoB2Qw55VzEFzZ=0QCGow@mail.gmail.com> (raw)
In-Reply-To: <20200710154811.418214-1-mgamal@redhat.com>

On Fri, Jul 10, 2020 at 8:48 AM Mohammed Gamal <mgamal@redhat.com> wrote:
>
> When EPT is enabled, KVM does not really look at guest physical
> address size. Address bits above maximum physical memory size are reserved.
> Because KVM does not look at these guest physical addresses, it currently
> effectively supports guest physical address sizes equal to the host.
>
> This can be problem when having a mixed setup of machines with 5-level page
> tables and machines with 4-level page tables, as live migration can change
> MAXPHYADDR while the guest runs, which can theoretically introduce bugs.

Huh? Changing MAXPHYADDR while the guest runs should be illegal. Or
have I missed some peculiarity of LA57 that makes MAXPHYADDR a dynamic
CPUID information field?

> In this patch series we add checks on guest physical addresses in EPT
> violation/misconfig and NPF vmexits and if needed inject the proper
> page faults in the guest.
>
> A more subtle issue is when the host MAXPHYADDR is larger than that of the
> guest. Page faults caused by reserved bits on the guest won't cause an EPT
> violation/NPF and hence we also check guest MAXPHYADDR and add PFERR_RSVD_MASK
> error code to the page fault if needed.

  parent reply	other threads:[~2020-07-10 16:31 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
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 ` Jim Mattson [this message]
2020-07-10 17:06   ` [PATCH v3 0/9] KVM: Support guest MAXPHYADDR < host MAXPHYADDR 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='CALMp9eRfZ50iyrED0-LU75VWhHu_kVoB2Qw55VzEFzZ=0QCGow@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.