From: Joerg Roedel <joro@8bytes.org>
To: Alexander Graf <agraf@suse.de>
Cc: "Roedel, Joerg" <joerg.roedel@amd.com>,
Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] KVM: SVM: Clean up rip handling in vmrun emulation
Date: Sat, 4 Sep 2010 21:32:42 +0200 [thread overview]
Message-ID: <20100904193241.GB8162@8bytes.org> (raw)
In-Reply-To: <1E478B32-8E9D-4041-B841-F64016FA5AB1@suse.de>
On Fri, Sep 03, 2010 at 11:29:11PM +0200, Alexander Graf wrote:
> Any reason we can't use the next_rip information here? A hypervisor
> could potentially do badness and put a prefix here, thus break all the
> logic, right?
Next_rip is not available on older hardware. Yes, this problem exists in
theory (as it does with rdmsr/wrmsr, cpuid, ... too). But a fix for this
on non-next-rip capable hardware would involve the instruction emulator
and kills all performance there. So we use this stupid and fast solution
here which works for all hypervisors I tested :-)
> (yes, I know, I wrote that code, but still ...)
When you wrote that code next_rip capable hardware was not available, so
don't worry :-)
Joerg
next prev parent reply other threads:[~2010-09-04 19:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 15:29 [PATCH 0/3] KVM fixes and cleanups Joerg Roedel
2010-09-02 15:29 ` [PATCH 1/3] KVM: MMU: Fix 32 bit legacy paging with NPT Joerg Roedel
2010-09-02 15:56 ` Avi Kivity
2010-09-02 16:32 ` Roedel, Joerg
2010-09-02 15:29 ` [PATCH 2/3] KVM: SVM: Restore correct registers after sel_cr0 intercept emulation Joerg Roedel
2010-09-02 16:02 ` Avi Kivity
2010-09-02 16:29 ` Roedel, Joerg
2010-09-05 7:09 ` Avi Kivity
2010-09-02 15:29 ` [PATCH 3/3] KVM: SVM: Clean up rip handling in vmrun emulation Joerg Roedel
2010-09-03 12:21 ` Roedel, Joerg
2010-09-03 21:29 ` Alexander Graf
2010-09-04 19:32 ` Joerg Roedel [this message]
2010-09-06 18:26 ` [PATCH 0/3] KVM fixes and cleanups Marcelo Tosatti
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