From b045ae906b42afb361dc7ecf1a3cea110fb0a65f Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 14 Apr 2020 22:47:45 +0000 Subject: [PATCH] kvm: nVMX: reflect MTF VM-exits if injected by L1 According to SDM 26.6.2, it is possible to inject an MTF VM-exit via the VM-entry interruption-information field regardless of the 'monitor trap flag' VM-execution control. KVM appropriately copies the VM-entry interruption-information field from vmcs12 to vmcs02. However, if L1 has not set the 'monitor trap flag' VM-execution control, KVM fails to reflect the subsequent MTF VM-exit into L1. Fix this by consulting the VM-entry interruption-information field of vmcs12 to determine if L1 has injected the MTF VM-exit. If so, reflect the exit, regardless of the 'monitor trap flag' VM-execution control. Fixes: 5f3d45e7f282 ("kvm/x86: add support for MONITOR_TRAP_FLAG") Signed-off-by: Oliver Upton Reviewed-by: Peter Shier Reviewed-by: Jim Mattson Message-Id: <20200414224746.240324-1-oupton@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index cbc9ea2..0d1400f 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -5533,6 +5533,23 @@ static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu, return 1 & (b >> (field & 7)); } +static bool nested_vmx_exit_handled_mtf(struct vmcs12 *vmcs12) +{ + u32 entry_intr_info = vmcs12->vm_entry_intr_info_field; + + if (nested_cpu_has_mtf(vmcs12)) + return true; + + /* + * An MTF VM-exit may be injected into the guest by setting the + * interruption-type to 7 (other event) and the vector field to 0. Such + * is the case regardless of the 'monitor trap flag' VM-execution + * control. + */ + return entry_intr_info == (INTR_INFO_VALID_MASK + | INTR_TYPE_OTHER_EVENT); +} + /* * Return 1 if we should exit from L2 to L1 to handle an exit, or 0 if we * should handle it ourselves in L0 (and then continue L2). Only call this @@ -5633,7 +5650,7 @@ bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason) case EXIT_REASON_MWAIT_INSTRUCTION: return nested_cpu_has(vmcs12, CPU_BASED_MWAIT_EXITING); case EXIT_REASON_MONITOR_TRAP_FLAG: - return nested_cpu_has_mtf(vmcs12); + return nested_vmx_exit_handled_mtf(vmcs12); case EXIT_REASON_MONITOR_INSTRUCTION: return nested_cpu_has(vmcs12, CPU_BASED_MONITOR_EXITING); case EXIT_REASON_PAUSE_INSTRUCTION: -- 2.7.4