From: Vitaly Kuznetsov vkuznets@redhat.com
commit 8d68bad6d869fae8f4d50ab6423538dec7da72d1 upstream.
Windows Server 2022 with Hyper-V role enabled failed to boot on KVM when enlightened VMCS is advertised. Debugging revealed there are two exposed secondary controls it is not happy with: SECONDARY_EXEC_ENABLE_VMFUNC and SECONDARY_EXEC_SHADOW_VMCS. These controls are known to be unsupported, as there are no corresponding fields in eVMCSv1 (see the comment above EVMCS1_UNSUPPORTED_2NDEXEC definition).
Previously, commit 31de3d2500e4 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()") introduced the required filtering mechanism for VMX MSRs but for some reason put only known to be problematic (and not full EVMCS1_UNSUPPORTED_* lists) controls there.
Note, Windows Server 2022 seems to have gained some sanity check for VMX MSRs: it doesn't even try to launch a guest when there's something it doesn't like, nested_evmcs_check_controls() mechanism can't catch the problem.
Let's be bold this time and instead of playing whack-a-mole just filter out all unsupported controls from VMX MSRs.
Fixes: 31de3d2500e4 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()") Signed-off-by: Vitaly Kuznetsov vkuznets@redhat.com Message-Id: 20210907163530.110066-1-vkuznets@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/vmx/evmcs.c | 12 +++++++++--- arch/x86/kvm/vmx/vmx.c | 9 +++++---- 2 files changed, 14 insertions(+), 7 deletions(-)
--- a/arch/x86/kvm/vmx/evmcs.c +++ b/arch/x86/kvm/vmx/evmcs.c @@ -352,14 +352,20 @@ void nested_evmcs_filter_control_msr(u32 switch (msr_index) { case MSR_IA32_VMX_EXIT_CTLS: case MSR_IA32_VMX_TRUE_EXIT_CTLS: - ctl_high &= ~VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL; + ctl_high &= ~EVMCS1_UNSUPPORTED_VMEXIT_CTRL; break; case MSR_IA32_VMX_ENTRY_CTLS: case MSR_IA32_VMX_TRUE_ENTRY_CTLS: - ctl_high &= ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL; + ctl_high &= ~EVMCS1_UNSUPPORTED_VMENTRY_CTRL; break; case MSR_IA32_VMX_PROCBASED_CTLS2: - ctl_high &= ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES; + ctl_high &= ~EVMCS1_UNSUPPORTED_2NDEXEC; + break; + case MSR_IA32_VMX_PINBASED_CTLS: + ctl_high &= ~EVMCS1_UNSUPPORTED_PINCTRL; + break; + case MSR_IA32_VMX_VMFUNC: + ctl_low &= ~EVMCS1_UNSUPPORTED_VMFUNC; break; }
--- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1867,10 +1867,11 @@ static int vmx_get_msr(struct kvm_vcpu * &msr_info->data)) return 1; /* - * Enlightened VMCS v1 doesn't have certain fields, but buggy - * Hyper-V versions are still trying to use corresponding - * features when they are exposed. Filter out the essential - * minimum. + * Enlightened VMCS v1 doesn't have certain VMCS fields but + * instead of just ignoring the features, different Hyper-V + * versions are either trying to use them and fail or do some + * sanity checking and refuse to boot. Filter all unsupported + * features out. */ if (!msr_info->host_initiated && vmx->nested.enlightened_vmcs_enabled)