[PATCH 6/6] KVM: VMX: pass a proper reason in kvm_emulate_instruction()

From: David Edmondson
Date: Mon Apr 12 2021 - 09:10:04 EST


From: Joao Martins <joao.m.martins@xxxxxxxxxx>

Declare various causes of emulation and use them as appropriate.

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Signed-off-by: David Edmondson <david.edmondson@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 5 +++++
arch/x86/kvm/vmx/vmx.c | 17 +++++++++--------
2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e1284680cbdc..f401e7c79ded 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1541,6 +1541,11 @@ enum {
EMULREASON_SVM_CR,
EMULREASON_SVM_DR,
EMULREASON_SVM_AVIC_UNACCEL,
+ EMULREASON_VMX_APIC_ACCESS,
+ EMULREASON_VMX_EPT_VIOLATION,
+ EMULREASON_VMX_DESC,
+ EMULREASON_VMX_INV_GUEST,
+ EMULREASON_VMX_RMODE_EX,
};

int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 037b01b5a54b..799eb0713b76 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1600,7 +1600,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
#endif
kvm_rip_write(vcpu, rip);
} else {
- if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP, 0))
+ if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP, EMULREASON_SKIP))
return 0;
}

@@ -4738,7 +4738,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
* Cause the #SS fault with 0 error code in VM86 mode.
*/
if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0) {
- if (kvm_emulate_instruction(vcpu, 0, 0)) {
+ if (kvm_emulate_instruction(vcpu, 0, EMULREASON_VMX_RMODE_EX)) {
if (vcpu->arch.halt_request) {
vcpu->arch.halt_request = 0;
return kvm_vcpu_halt(vcpu);
@@ -4816,7 +4816,8 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
return 1;
}
- return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP, 0);
+ return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP,
+ EMULREASON_GP);
}

/*
@@ -4930,7 +4931,7 @@ static int handle_io(struct kvm_vcpu *vcpu)
++vcpu->stat.io_exits;

if (string)
- return kvm_emulate_instruction(vcpu, 0, 0);
+ return kvm_emulate_instruction(vcpu, 0, EMULREASON_IO);

port = exit_qualification >> 16;
size = (exit_qualification & 7) + 1;
@@ -5004,7 +5005,7 @@ static int handle_set_cr4(struct kvm_vcpu *vcpu, unsigned long val)
static int handle_desc(struct kvm_vcpu *vcpu)
{
WARN_ON(!(vcpu->arch.cr4 & X86_CR4_UMIP));
- return kvm_emulate_instruction(vcpu, 0, 0);
+ return kvm_emulate_instruction(vcpu, 0, EMULREASON_VMX_DESC);
}

static int handle_cr(struct kvm_vcpu *vcpu)
@@ -5244,7 +5245,7 @@ static int handle_apic_access(struct kvm_vcpu *vcpu)
return kvm_skip_emulated_instruction(vcpu);
}
}
- return kvm_emulate_instruction(vcpu, 0, 0);
+ return kvm_emulate_instruction(vcpu, 0, EMULREASON_VMX_APIC_ACCESS);
}

static int handle_apic_eoi_induced(struct kvm_vcpu *vcpu)
@@ -5375,7 +5376,7 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
* reconstruct the page fault error code.
*/
if (unlikely(allow_smaller_maxphyaddr && kvm_vcpu_is_illegal_gpa(vcpu, gpa)))
- return kvm_emulate_instruction(vcpu, 0, 0);
+ return kvm_emulate_instruction(vcpu, 0, EMULREASON_VMX_EPT_VIOLATION);

return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
}
@@ -5424,7 +5425,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
if (kvm_test_request(KVM_REQ_EVENT, vcpu))
return 1;

- if (!kvm_emulate_instruction(vcpu, 0, 0))
+ if (!kvm_emulate_instruction(vcpu, 0, EMULREASON_VMX_INV_GUEST))
return 0;

if (vmx->emulation_required && !vmx->rmode.vm86_active &&
--
2.30.2