@@ -2019,8 +2019,8 @@ u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu);
* VMware backdoor emulation handles select instructions
* and reinjects the #GP for all other cases.
*
- * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which
- * case the CR2/GPA value pass on the stack is valid.
+ * EMULTYPE_PF - Set when an intercepted #PF triggers the emulation, in which case
+ * the CR2/GPA value pass on the stack is valid.
*
* EMULTYPE_COMPLETE_USER_EXIT - Set when the emulator should update interruptibility
* state and inject single-step #DBs after skipping
@@ -2055,6 +2055,11 @@ u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu);
#define EMULTYPE_COMPLETE_USER_EXIT (1 << 7)
#define EMULTYPE_WRITE_PF_TO_SP (1 << 8)
+static inline bool kvm_can_emulate_event_vectoring(int emul_type)
+{
+ return !(emul_type & EMULTYPE_PF);
+}
+
int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);
int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
void *insn, int insn_len);
@@ -1705,6 +1705,12 @@ int vmx_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,
kvm_queue_exception(vcpu, UD_VECTOR);
return X86EMUL_PROPAGATE_FAULT;
}
+
+ /* Check that emulation is possible during event vectoring */
+ if ((to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
+ !kvm_can_emulate_event_vectoring(emul_type))
+ return X86EMUL_UNHANDLEABLE_VECTORING;
+
return X86EMUL_CONTINUE;
}
@@ -6543,26 +6549,15 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
return 0;
}
- /*
- * Note:
- * Do not try to fix EXIT_REASON_EPT_MISCONFIG if it caused by
- * delivery event since it indicates guest is accessing MMIO.
- * The vm-exit can be triggered again after return to guest that
- * will cause infinite loop.
- */
if ((vectoring_info & VECTORING_INFO_VALID_MASK) &&
(exit_reason.basic != EXIT_REASON_EXCEPTION_NMI &&
exit_reason.basic != EXIT_REASON_EPT_VIOLATION &&
exit_reason.basic != EXIT_REASON_PML_FULL &&
exit_reason.basic != EXIT_REASON_APIC_ACCESS &&
exit_reason.basic != EXIT_REASON_TASK_SWITCH &&
- exit_reason.basic != EXIT_REASON_NOTIFY)) {
- gpa_t gpa = INVALID_GPA;
-
- if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG)
- gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
-
- kvm_prepare_event_vectoring_exit(vcpu, gpa);
+ exit_reason.basic != EXIT_REASON_NOTIFY &&
+ exit_reason.basic != EXIT_REASON_EPT_MISCONFIG)) {
+ kvm_prepare_event_vectoring_exit(vcpu, INVALID_GPA);
return 0;
}
Move unhandleable vmexit during vectoring error detection into check_emulate_instruction. Implement the function which prohibits the emulation if EMULTYPE_PF is set when vectoring, otherwise such a situation may occur: 1. CPU executes an instruction and hits a #GP 2. While vectoring the #GP, a shadow #PF occurs 3. On vmexit, KVM re-injects #GP 4. KVM emulates because of the write-protected page 5. KVM "successfully" emulates and also detects the #GP 6. KVM synthesizes a #GP, and since #GP has already been injected, incorrectly escalates to a #DF. Fix the comment about EMULTYPE_PF as this flag doesn't necessarily mean MMIO anymore: it can also be set due to the write protection violation. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Ivan Orlov <iorlov@amazon.com> --- V1 -> V2: - Detect the unhandleable vectoring error in vmx_check_emulate_instruction instead of handling it in the common MMU code (which is specific for cached MMIO) V2 -> V3: - Prohibit any emulation during vectoring if it happens due to an intercepted #PF. arch/x86/include/asm/kvm_host.h | 9 +++++++-- arch/x86/kvm/vmx/vmx.c | 23 +++++++++-------------- 2 files changed, 16 insertions(+), 16 deletions(-)