On 1/18/22 15:22, Vitaly Kuznetsov wrote:
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)
Yes, it is. I have queued the patch, and feel free to send a 5.16 backport too.
Paolo
