Re: [PATCH v8 0/9] i386: KVM: expand Hyper-V features early

[Eduardo Habkost]

On Tue, Jun 08, 2021 at 02:08:08PM +0200, Vitaly Kuznetsov wrote:
> Changes since v7:
> - Make eVMCS version check future proof [Eduardo]
> - Collect R-b tags [Eduardo]
> - Drop 'if (!strcmp(arch, "i386") || !strcmp(arch, "x86_64"))' check from 
> qtest
>  [Eduardo]
> - s/priviliges/privileges/ [Eric]
> 
> The last two functional patches are inspired by 'Fine-grained access check
> to Hyper-V hypercalls and MSRs' work for KVM:
> https://lore.kernel.org/kvm/20210521095204.2161214-1-vkuznets@redhat.com/
> 
> Original description:
> 
> Upper layer tools like libvirt want to figure out which Hyper-V features are
> supported by the underlying stack (QEMU/KVM) but currently they are unable to
> do so. We have a nice 'hv_passthrough' CPU flag supported by QEMU but it has
> no effect on e.g. QMP's 
> 
> query-cpu-model-expansion type=full 
> model={"name":"host","props":{"hv-passthrough":true}}
> 
> command as we parse Hyper-V features after creating KVM vCPUs and not at
> feature expansion time. To support the use-case we first need to make 
> KVM_GET_SUPPORTED_HV_CPUID ioctl a system-wide ioctl as the existing
> vCPU version can't be used that early. This is what KVM part does. With
> that done, we can make early Hyper-V feature expansion (this series).

I'm finally queueing this (please ignore my reply to v7).
Thanks, and sorry for the delay!

-- 
Eduardo