From: Gleb Natapov <gleb@redhat.com>
To: Stefan Bader <stefan.bader@canonical.com>
Cc: kvm@vger.kernel.org, Avi Kivity <avi@redhat.com>,
Andy Whitcroft <apw@canonical.com>
Subject: Re: Nested kvm_intel broken on pre 3.3 hosts
Date: Wed, 1 Aug 2012 16:39:40 +0300 [thread overview]
Message-ID: <20120801133940.GB27579@redhat.com> (raw)
In-Reply-To: <50191307.5030107@canonical.com>
On Wed, Aug 01, 2012 at 01:29:11PM +0200, Stefan Bader wrote:
> I have been looking at a report[1] about the kvm_intel module failing to load on
> linux v3.3 and newer guests when running on a v3.2 host. Bisection turned up the
> following patch:
>
> commit fee84b079d5ddee2247b5c1f53162c330c622902
> Author: Avi Kivity <avi@redhat.com>
> Date: Thu Nov 10 14:57:25 2011 +0200
>
> KVM: VMX: Intercept RDPMC
>
> Intercept RDPMC and forward it to the PMU emulation code.
>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
>
> It looks like requiring the feature based on cpu fails when the host (outer kvm
> module) code does not support it. So maybe that should be optional instead of
> required?
According to Intel SDM there was never CPU that didn't support RDPMC
exiting. Looks like unfortunate nested VMX bug.
> Seems also like kvm_amd does not "suffer" from any test that could fail and
> should be ok (though I did not test it personally).
>
> -Stefan
>
> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1031090
>
--
Gleb.
next prev parent reply other threads:[~2012-08-01 13:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-01 11:29 Nested kvm_intel broken on pre 3.3 hosts Stefan Bader
2012-08-01 13:39 ` Gleb Natapov [this message]
2012-08-01 14:08 ` Avi Kivity
2012-08-01 14:26 ` Stefan Bader
2012-08-01 14:29 ` Avi Kivity
2012-08-01 15:07 ` Nadav Har'El
2012-08-01 15:10 ` Gleb Natapov
2012-08-01 15:11 ` Avi Kivity
2012-08-02 15:19 ` Stefan Bader
2012-08-02 15:19 ` [PATCH 1/7] KVM: Move cpuid code to new file Stefan Bader
2012-08-02 15:19 ` [PATCH 2/7] KVM: expose latest Intel cpu new features (BMI1/BMI2/FMA/AVX2) to guest Stefan Bader
2012-08-02 15:19 ` [PATCH 3/7] KVM: Expose kvm_lapic_local_deliver() Stefan Bader
2012-08-02 15:19 ` [PATCH 4/7] KVM: Expose a version 2 architectural PMU to a guests Stefan Bader
2012-08-02 15:19 ` [PATCH 5/7] KVM: Add generic RDPMC support Stefan Bader
2012-08-02 15:19 ` [PATCH 6/7] KVM: SVM: Intercept RDPMC Stefan Bader
2012-08-02 15:19 ` [PATCH 7/7] KVM: VMX: " Stefan Bader
2012-08-02 15:26 ` Nested kvm_intel broken on pre 3.3 hosts Avi Kivity
2012-08-03 10:55 ` (unknown), Stefan Bader
2012-08-03 10:57 ` Nested kvm_intel broken on pre 3.3 hosts Stefan Bader
2012-08-05 9:18 ` Avi Kivity
2012-08-06 14:40 ` Stefan Bader
2012-08-09 7:13 ` Stefan Bader
2012-08-09 9:34 ` Avi Kivity
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