Re: [PATCH RFC 2/3] x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()

From: Sean Christopherson
Date: Wed Jan 15 2020 - 18:27:42 EST


On Wed, Jan 15, 2020 at 06:10:13PM +0100, Vitaly Kuznetsov wrote:
> With fine grained VMX feature enablement QEMU>=4.2 tries to do KVM_SET_MSRS
> with default (matching CPU model) values and in case eVMCS is also enabled,
> fails.

As in, Qemu is blindly throwing values at KVM and complains on failure?
That seems like a Qemu bug, especially since Qemu needs to explicitly do
KVM_CAP_HYPERV_ENLIGHTENED_VMCS to enable eVMCS.