From: Joerg Roedel <joro@8bytes.org>
To: Bandan Das <bsd@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
kvm@vger.kernel.org, "Dirk Müller" <dmueller@suse.com>
Subject: Re: [PATCH] Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS
Date: Tue, 6 Oct 2015 12:23:29 +0200 [thread overview]
Message-ID: <20151006102329.GC20886@8bytes.org> (raw)
In-Reply-To: <jpg7fn1tdnw.fsf@linux.bootlegged.copy>
On Mon, Oct 05, 2015 at 01:42:43PM -0400, Bandan Das wrote:
> Joerg Roedel <joro@8bytes.org> writes:
>
> > On Mon, Oct 05, 2015 at 12:54:43PM -0400, Bandan Das wrote:
> >> Joerg Roedel <joro@8bytes.org> writes:
> >> The problems is that the next_rip field could be stale. If the processor supports
> >> next_rip, then it will clear it out on the next entry. If it doesn't,
> >> an old value just sits there (no matter who wrote it) and the problem
> >> happens when skip_emulated_instruction advances the rip with an incorrect
> >> value.
> >
> > So the right fix would be to just set the guests next_rip to 0 when we
> > emulate vmrun, just like real hardware does, no?
>
> Agreed, resetting to 0 if nrips isn't supported seems right. It would still
> help having a printk_once in this case IMO :)
I meant to reset it always to 0 on vmrun, like real hardware does.
Joerg
next prev parent reply other threads:[~2015-10-06 10:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-01 11:43 [PATCH] Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS Dirk Müller
2015-10-01 12:25 ` Paolo Bonzini
2015-10-01 12:45 ` Dirk Müller
2015-10-01 12:31 ` Paolo Bonzini
2015-10-01 22:31 ` Bandan Das
2015-10-02 6:43 ` Dirk Müller
2015-10-05 1:15 ` Bandan Das
2015-10-05 9:50 ` Joerg Roedel
2015-10-05 16:54 ` Bandan Das
2015-10-05 17:15 ` Joerg Roedel
2015-10-05 17:42 ` Bandan Das
2015-10-06 10:23 ` Joerg Roedel [this message]
2015-10-06 18:02 ` Bandan Das
2015-10-05 20:12 ` Dirk Müller
2015-10-05 22:00 ` Bandan Das
2015-10-06 10:28 ` Joerg Roedel
2015-10-06 17:59 ` Bandan Das
2015-10-07 11:03 ` Joerg Roedel
2015-10-07 12:47 ` [PATCH] kvm: svm: Only propagate next_rip when guest supports it Joerg Roedel
2015-10-07 12:57 ` kbuild test robot
2015-10-07 15:48 ` Bandan Das
2015-10-07 16:14 ` Joerg Roedel
2015-10-07 17:03 ` Dirk Müller
2015-10-07 14:58 ` [PATCH] Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS Bandan Das
2015-10-07 15:24 ` Joerg Roedel
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