From: Avi Kivity <avi@redhat.com>
To: Stefan Bader <stefan.bader@canonical.com>
Cc: Gleb Natapov <gleb@redhat.com>,
kvm@vger.kernel.org, Andy Whitcroft <apw@canonical.com>
Subject: Re: Nested kvm_intel broken on pre 3.3 hosts
Date: Wed, 01 Aug 2012 17:29:18 +0300 [thread overview]
Message-ID: <50193D3E.9090100@redhat.com> (raw)
In-Reply-To: <50193C94.1030809@canonical.com>
On 08/01/2012 05:26 PM, Stefan Bader wrote:
>>> According to Intel SDM there was never CPU that didn't support RDPMC
>>> exiting. Looks like unfortunate nested VMX bug.
>>
>> Moreover, that same commit fixes the bug in nested vmx. So if you
>> update your host kernel to the same version as your L1 guest (or, at
>> your option, any later version) it should work.
>>
>> We could backport that part of the patch, though as nested vmx is still
>> experimential, I don't think it's worth it.
>>
> Though this is probably what people will (or will have to) do. The host is not
> always under your control. Even with it being experimental, it was working (at
> least the module was loadable) before and is now broken on Intel hosts.
> But ok, so the recommendation is to rather backport support to the host kernel
> than to try handling this differently in the guest module, right?
Right - it's not just kvm-as-a-guest that will trip on this. But
there's no point in everyone backporting it on their own. If you're
doing the backport, please post it here and we'll forward it to the
stable branch.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-08-01 14:29 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
2012-08-01 14:08 ` Avi Kivity
2012-08-01 14:26 ` Stefan Bader
2012-08-01 14:29 ` Avi Kivity [this message]
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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