From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Cc: kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>,
linux-kernel@vger.kernel.org, Liran Alon <liran.alon@oracle.com>,
Roman Kagan <rkagan@virtuozzo.com>
Subject: Re: [PATCH RFC 2/3] x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()
Date: Mon, 27 Jan 2020 22:52:24 +0100 [thread overview]
Message-ID: <87tv4glg87.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <437c2710-7148-a675-8945-71dc7a90f7dd@redhat.com>
Paolo Bonzini <pbonzini@redhat.com> writes:
> On 27/01/20 16:38, Vitaly Kuznetsov wrote:
>>>> If there are no objections and if we still think it would be beneficial
>>>> to minimize the list of controls we filter out (and not go with the full
>>>> set like my RFC suggests), I'll prepare v2. (v1, actually, this was RFC).
>>> One last idea, can we keep the MSR filtering as is and add the hack in
>>> vmx_restore_control_msr()? That way the (userspace) host and guest see
>>> the same values when reading the affected MSRs, and eVMCS wouldn't need
>>> it's own hook to do consistency checks.
>> Yes but (if I'm not mistaken) we'll have then to keep the filtering we
>> currently do in nested_enable_evmcs(): if userspace doesn't do
>> KVM_SET_MSR for VMX MSRs (QEMU<4.2) then the filtering in
>> vmx_restore_control_msr() won't happen and the guest will see the
>> unfiltered set of controls...
>>
>
> Indeed. The place you used in the RFC is the best we can do, I am afraid.
>
In case we decide to filter out the full set of unsupported stuff
there's basically nothing to change, feel free to just treat the RFC as
non-RFC :-) (and personally, I'd prefer to keep the 'full set' in the
filter as it is less fragile; the 'short list' I came up with is the
result of my experiments on one hardware host only and I'm not sure what
may make Hyper-V behave differently).
I can re-submit, of course, if needed.
--
Vitaly
next prev parent reply other threads:[~2020-01-27 21:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 17:10 [PATCH RFC 0/3] x86/kvm/hyper-v: fix enlightened VMCS & QEMU4.2 Vitaly Kuznetsov
2020-01-15 17:10 ` [PATCH RFC 1/3] x86/kvm/hyper-v: remove stale evmcs_already_enabled check from nested_enable_evmcs() Vitaly Kuznetsov
2020-01-15 22:50 ` Liran Alon
2020-01-15 17:10 ` [PATCH RFC 2/3] x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs() Vitaly Kuznetsov
2020-01-15 22:49 ` Liran Alon
2020-01-16 8:37 ` Vitaly Kuznetsov
2020-02-03 15:11 ` Vitaly Kuznetsov
2020-01-15 23:27 ` Sean Christopherson
2020-01-15 23:30 ` Liran Alon
2020-01-16 8:51 ` Vitaly Kuznetsov
2020-01-16 16:19 ` Sean Christopherson
2020-01-16 16:57 ` Vitaly Kuznetsov
2020-01-17 6:31 ` Sean Christopherson
2020-01-18 21:42 ` Paolo Bonzini
2020-01-19 8:54 ` Paolo Bonzini
2020-01-22 5:47 ` Sean Christopherson
2020-01-22 9:37 ` Vitaly Kuznetsov
2020-01-22 14:33 ` Paolo Bonzini
2020-01-22 15:08 ` Vitaly Kuznetsov
2020-01-22 15:51 ` Sean Christopherson
2020-01-22 16:29 ` Vitaly Kuznetsov
2020-01-22 16:40 ` Paolo Bonzini
2020-01-23 9:15 ` Vitaly Kuznetsov
2020-01-23 19:09 ` Vitaly Kuznetsov
2020-01-24 17:25 ` Sean Christopherson
2020-01-27 15:38 ` Vitaly Kuznetsov
2020-01-27 17:53 ` Paolo Bonzini
2020-01-27 21:52 ` Vitaly Kuznetsov [this message]
2020-01-27 18:17 ` Sean Christopherson
2020-01-15 17:10 ` [PATCH RFC 3/3] x86/kvm/hyper-v: don't allow to turn on unsupported VMX controls for nested guests Vitaly Kuznetsov
2020-01-15 22:59 ` Liran Alon
2020-01-16 8:55 ` Vitaly Kuznetsov
2020-01-16 16:21 ` Sean Christopherson
2020-01-19 8:57 ` Paolo Bonzini
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