From: Paolo Bonzini <pbonzini@redhat.com>
To: Jim Mattson <jmattson@google.com>, Wanpeng Li <kernellwp@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
"kvm list" <kvm@vger.kernel.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Wanpeng Li" <wanpeng.li@hotmail.com>
Subject: Re: [PATCH v2] KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0
Date: Thu, 2 Nov 2017 18:35:44 +0100 [thread overview]
Message-ID: <6e8a071e-0d5a-45d2-b2ef-4f6172ef4cff@redhat.com> (raw)
In-Reply-To: <CALMp9eQFEVLwV8ZW3HtO__rOfEd1Qs-ZJvqwT-5SAmU2zRonvA@mail.gmail.com>
On 19/10/2017 20:09, Jim Mattson wrote:
> "(offset & 0x3) == 1" seems like an obfuscated way of writing the
> predicate, is_mci_status_msr(msr). But other than that, this change
> looks fine to me.
>
> I'm a little more concerned about the code above. At the very least,
> it needs to let the host set an arbitrary value for save/restore to
> work.
Why? The guest cannot have written anything but the three allowed
values, userspace cannot write anything else either outside save/restore
without KVM_SET_MSR failing, and KVM itself (specifically
kvm_vcpu_ioctl_x86_setup_mce) only ever initializes IA32_MCi_CTL to all
ones. So save will only ever find those three values, and restore's
KVM_SET_MSR restore should never fail either.
Thanks,
Paolo
> Reviewed-by: Jim Mattson <jmattson@google.com>
next prev parent reply other threads:[~2017-11-02 17:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-19 13:47 Wanpeng Li
2017-10-19 18:09 ` Jim Mattson
2017-11-02 17:35 ` Paolo Bonzini [this message]
2017-11-02 18:57 ` Jim Mattson
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=6e8a071e-0d5a-45d2-b2ef-4f6172ef4cff@redhat.com \
--to=pbonzini@redhat.com \
--cc=jmattson@google.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rkrcmar@redhat.com \
--cc=wanpeng.li@hotmail.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
all inboxes | Powered by JetHome®