From: Gleb Natapov <gleb@redhat.com>
To: Mohammed Gamal <m.gamal005@gmail.com>
Cc: avi@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCHv2] KVM: inject #UD if instruction emulation fails and exit to userspace
Date: Mon, 10 May 2010 20:33:37 +0300 [thread overview]
Message-ID: <20100510173337.GD4497@redhat.com> (raw)
In-Reply-To: <y2j52d4a3891005100906g1353b394h76ce675fe98f73bc@mail.gmail.com>
On Mon, May 10, 2010 at 07:06:05PM +0300, Mohammed Gamal wrote:
> On Mon, May 10, 2010 at 1:25 PM, Gleb Natapov <gleb@redhat.com> wrote:
> > On Mon, May 10, 2010 at 11:16:56AM +0300, Gleb Natapov wrote:
> >> Do not kill VM when instruction emulation fails. Inject #UD and report
> >> failure to userspace instead. Userspace may choose to reenter guest if
> >> vcpu is in userspace (cpl == 3) in which case guest OS will kill
> >> offending process and continue running.
> >>
>
> I am curious to know what'd happen in case the vcpu is in kernel space
> (cpl == 0). Is that case handled?
>
Currently no matter where emulation fails VM is stopped and cpu state is
printed on stderr. After that patch userspace may choose to continue VM
execution after emulation error (#UD will be injected into VM though). The
policy is in userspace, but I don't see the point to continue execution
after emulation failed in kernel. How kernel can recover from the #UD?
--
Gleb.
next prev parent reply other threads:[~2010-05-10 17:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-10 8:16 [PATCHv2] KVM: inject #UD if instruction emulation fails and exit to userspace Gleb Natapov
2010-05-10 10:25 ` Gleb Natapov
2010-05-10 16:06 ` Mohammed Gamal
2010-05-10 17:33 ` Gleb Natapov [this message]
2010-05-11 2:09 ` Takuya Yoshikawa
2010-05-11 16:47 ` Marcelo Tosatti
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