[PATCH 3/6] KVM: x86: add emulation_reason to kvm_emulate_instruction()

From: David Edmondson
Date: Mon Apr 12 2021 - 09:10:00 EST


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

Allow kvm_emulate_instruction() callers to provide the cause of
instruction emulation, which is then passed along to
x86_emulation_instruction().

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Signed-off-by: David Edmondson <david.edmondson@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 10 ++++++++--
arch/x86/kvm/svm/avic.c | 2 +-
arch/x86/kvm/svm/svm.c | 12 ++++++------
arch/x86/kvm/vmx/vmx.c | 16 ++++++++--------
arch/x86/kvm/x86.c | 16 ++++++++++------
5 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3768819693e5..556dc51e322a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1527,9 +1527,15 @@ extern u64 kvm_mce_cap_supported;
#define EMULTYPE_VMWARE_GP (1 << 5)
#define EMULTYPE_PF (1 << 6)

-int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);
+enum {
+ EMULREASON_UNKNOWN = 0,
+};
+
+int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type,
+ int emulation_reason);
int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
- void *insn, int insn_len);
+ void *insn, int insn_len,
+ int emulation_reason);

void kvm_enable_efer_bits(u64);
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 78bdcfac4e40..31a17fa6a37c 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -558,7 +558,7 @@ int avic_unaccelerated_access_interception(struct vcpu_svm *svm)
ret = avic_unaccel_trap_write(svm);
} else {
/* Handling Fault */
- ret = kvm_emulate_instruction(&svm->vcpu, 0);
+ ret = kvm_emulate_instruction(&svm->vcpu, 0, 0);
}

return ret;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 58a45bb139f8..bba3b72390a8 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -344,7 +344,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
}

if (!svm->next_rip) {
- if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP))
+ if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP, 0))
return 0;
} else {
kvm_rip_write(vcpu, svm->next_rip);
@@ -2077,7 +2077,7 @@ static int io_interception(struct vcpu_svm *svm)
if (sev_es_guest(vcpu->kvm))
return sev_es_string_io(svm, size, port, in);
else
- return kvm_emulate_instruction(vcpu, 0);
+ return kvm_emulate_instruction(vcpu, 0, 0);
}

svm->next_rip = svm->vmcb->control.exit_info_2;
@@ -2263,7 +2263,7 @@ static int gp_interception(struct vcpu_svm *svm)
*/
if (!is_guest_mode(vcpu))
return kvm_emulate_instruction(vcpu,
- EMULTYPE_VMWARE_GP | EMULTYPE_NO_DECODE);
+ EMULTYPE_VMWARE_GP | EMULTYPE_NO_DECODE, 0);
} else
return emulate_svm_instr(vcpu, opcode);

@@ -2459,7 +2459,7 @@ static int invd_interception(struct vcpu_svm *svm)
static int invlpg_interception(struct vcpu_svm *svm)
{
if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
- return kvm_emulate_instruction(&svm->vcpu, 0);
+ return kvm_emulate_instruction(&svm->vcpu, 0, 0);

kvm_mmu_invlpg(&svm->vcpu, svm->vmcb->control.exit_info_1);
return kvm_skip_emulated_instruction(&svm->vcpu);
@@ -2467,12 +2467,12 @@ static int invlpg_interception(struct vcpu_svm *svm)

static int emulate_on_interception(struct vcpu_svm *svm)
{
- return kvm_emulate_instruction(&svm->vcpu, 0);
+ return kvm_emulate_instruction(&svm->vcpu, 0, 0);
}

static int rsm_interception(struct vcpu_svm *svm)
{
- return kvm_emulate_instruction_from_buffer(&svm->vcpu, rsm_ins_bytes, 2);
+ return kvm_emulate_instruction_from_buffer(&svm->vcpu, rsm_ins_bytes, 2, 0);
}

static int rdpmc_interception(struct vcpu_svm *svm)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 32cf8287d4a7..037b01b5a54b 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))
+ if (!kvm_emulate_instruction(vcpu, EMULTYPE_SKIP, 0))
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)) {
+ if (kvm_emulate_instruction(vcpu, 0, 0)) {
if (vcpu->arch.halt_request) {
vcpu->arch.halt_request = 0;
return kvm_vcpu_halt(vcpu);
@@ -4816,7 +4816,7 @@ 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);
+ return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP, 0);
}

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

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

port = exit_qualification >> 16;
size = (exit_qualification & 7) + 1;
@@ -5004,7 +5004,7 @@ 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);
+ return kvm_emulate_instruction(vcpu, 0, 0);
}

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

static int handle_apic_eoi_induced(struct kvm_vcpu *vcpu)
@@ -5375,7 +5375,7 @@ 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);
+ return kvm_emulate_instruction(vcpu, 0, 0);

return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
}
@@ -5424,7 +5424,7 @@ 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))
+ if (!kvm_emulate_instruction(vcpu, 0, 0))
return 0;

if (vmx->emulation_required && !vmx->rmode.vm86_active &&
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b9225012ebd2..88519bf6bd00 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6197,7 +6197,7 @@ int handle_ud(struct kvm_vcpu *vcpu)
emul_type = EMULTYPE_TRAP_UD_FORCED;
}

- return kvm_emulate_instruction(vcpu, emul_type);
+ return kvm_emulate_instruction(vcpu, emul_type, 0);
}
EXPORT_SYMBOL_GPL(handle_ud);

@@ -7608,16 +7608,20 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
return r;
}

-int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type)
+int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type,
+ int emulation_reason)
{
- return x86_emulate_instruction(vcpu, 0, emulation_type, 0, NULL, 0);
+ return x86_emulate_instruction(vcpu, 0, emulation_type,
+ emulation_reason, NULL, 0);
}
EXPORT_SYMBOL_GPL(kvm_emulate_instruction);

int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
- void *insn, int insn_len)
+ void *insn, int insn_len,
+ int emulation_reason)
{
- return x86_emulate_instruction(vcpu, 0, 0, 0, insn, insn_len);
+ return x86_emulate_instruction(vcpu, 0, 0,
+ emulation_reason, insn, insn_len);
}
EXPORT_SYMBOL_GPL(kvm_emulate_instruction_from_buffer);

@@ -9339,7 +9343,7 @@ static inline int complete_emulated_io(struct kvm_vcpu *vcpu)
int r;

vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
- r = kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
+ r = kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE, 0);
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
return r;
}
--
2.30.2