Re: [PATCH v3 0/5] KVM: nVMX: Fix Windows 11 + WSL2 + Enlightened VMCS

From: Vitaly Kuznetsov
Date: Thu Jan 27 2022 - 04:36:41 EST


Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes:

> Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes:
>
>> Changes since v2 [Sean]:
>> - Tweak a comment in PATCH5.
>> - Add Reviewed-by: tags to PATCHes 3 and 5.
>>
>> Original description:
>>
>> Windows 11 with enabled Hyper-V role doesn't boot on KVM when Enlightened
>> VMCS interface is provided to it. The observed behavior doesn't conform to
>> Hyper-V TLFS. In particular, I'm observing 'VMREAD' instructions trying to
>> access field 0x4404 ("VM-exit interruption information"). TLFS, however, is
>> very clear this should not be happening:
>>
>> "Any VMREAD or VMWRITE instructions while an enlightened VMCS is active is
>> unsupported and can result in unexpected behavior."
>>
>> Microsoft confirms this is a bug in Hyper-V which is supposed to get fixed
>> eventually. For the time being, implement a workaround in KVM allowing
>> VMREAD instructions to read from the currently loaded Enlightened VMCS.
>>
>> Patches 1-2 are unrelated fixes to VMX feature MSR filtering when eVMCS is
>> enabled. Patches 3 and 4 are preparatory changes, patch 5 implements the
>> workaround.
>>
>
> Paolo,
>
> would it be possible to pick this up for 5.17? Technically, this is a
> "fix", even if the bug itself is not in KVM)

Ping)

--
Vitaly