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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 0/5] KVM: nVMX: Fix Windows 11 + WSL2 + Enlightened VMCS
Date: Tue, 14 Dec 2021 15:38:54 +0100	[thread overview]
Message-ID: <20211214143859.111602-1-vkuznets@redhat.com> (raw)

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.

Vitaly Kuznetsov (5):
  KVM: nVMX: Also filter MSR_IA32_VMX_TRUE_PINBASED_CTLS when eVMCS
  KVM: nVMX: eVMCS: Filter out VM_EXIT_SAVE_VMX_PREEMPTION_TIMER
  KVM: nVMX: Rename vmcs_to_field_offset{,_table} to
    vmcs12_field_offset{,_table}
  KVM: nVMX: Implement evmcs_field_offset() suitable for handle_vmread()
  KVM: nVMX: Allow VMREAD when Enlightened VMCS is in use

 arch/x86/kvm/vmx/evmcs.c  |  4 ++--
 arch/x86/kvm/vmx/evmcs.h  | 48 +++++++++++++++++++++++++++++++--------
 arch/x86/kvm/vmx/nested.c | 42 ++++++++++++++++++++++++----------
 arch/x86/kvm/vmx/vmcs12.c |  4 ++--
 arch/x86/kvm/vmx/vmcs12.h |  6 ++---
 5 files changed, 76 insertions(+), 28 deletions(-)

-- 
2.33.1


             reply	other threads:[~2021-12-14 14:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-14 14:38 Vitaly Kuznetsov [this message]
2021-12-14 14:38 ` [PATCH 1/5] KVM: nVMX: Also filter MSR_IA32_VMX_TRUE_PINBASED_CTLS when eVMCS Vitaly Kuznetsov
2021-12-14 14:38 ` [PATCH 2/5] KVM: nVMX: eVMCS: Filter out VM_EXIT_SAVE_VMX_PREEMPTION_TIMER Vitaly Kuznetsov
2021-12-14 14:38 ` [PATCH 3/5] KVM: nVMX: Rename vmcs_to_field_offset{,_table} to vmcs12_field_offset{,_table} Vitaly Kuznetsov
2022-01-06 23:36   ` Sean Christopherson
2022-01-07  8:45     ` Vitaly Kuznetsov
2021-12-14 14:38 ` [PATCH 4/5] KVM: nVMX: Implement evmcs_field_offset() suitable for handle_vmread() Vitaly Kuznetsov
2021-12-14 14:38 ` [PATCH 5/5] KVM: nVMX: Allow VMREAD when Enlightened VMCS is in use Vitaly Kuznetsov
2022-01-07  0:03   ` Sean Christopherson
2022-01-07  8:49     ` Vitaly Kuznetsov

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