KVM: VMX: Support for injecting software exceptions

VMX differentiates between processor and software generated exceptions
when injecting them into the guest. Extend vmx_queue_exception
accordingly (and refactor related constants) so that we can use this
service reliably for the new guest debugging framework.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 22 insertions, 16 deletions

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index d0238e6151d8..32159f034efc 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -270,8 +270,9 @@ enum vmcs_field {
 
 #define INTR_TYPE_EXT_INTR              (0 << 8) /* external interrupt */
 #define INTR_TYPE_NMI_INTR              (2 << 8) /* NMI */
-#define INTR_TYPE_EXCEPTION             (3 << 8) /* processor exception */
+#define INTR_TYPE_HARD_EXCEPTION        (3 << 8) /* processor exception */
 #define INTR_TYPE_SOFT_INTR             (4 << 8) /* software interrupt */
+#define INTR_TYPE_SOFT_EXCEPTION        (6 << 8) /* software exception */
 
 /* GUEST_INTERRUPTIBILITY_INFO flags. */
 #define GUEST_INTR_STATE_STI            0x00000001
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7611af576829..1d974c1eaa7d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -189,21 +189,21 @@ static inline int is_page_fault(u32 intr_info)
 {
         return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                              INTR_INFO_VALID_MASK)) ==
-                (INTR_TYPE_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
+                (INTR_TYPE_HARD_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_no_device(u32 intr_info)
 {
         return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                              INTR_INFO_VALID_MASK)) ==
-                (INTR_TYPE_EXCEPTION | NM_VECTOR | INTR_INFO_VALID_MASK);
+                (INTR_TYPE_HARD_EXCEPTION | NM_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_invalid_opcode(u32 intr_info)
 {
         return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
                              INTR_INFO_VALID_MASK)) ==
-                (INTR_TYPE_EXCEPTION | UD_VECTOR | INTR_INFO_VALID_MASK);
+                (INTR_TYPE_HARD_EXCEPTION | UD_VECTOR | INTR_INFO_VALID_MASK);
 }
 
 static inline int is_external_interrupt(u32 intr_info)
@@ -747,29 +747,33 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
                                 bool has_error_code, u32 error_code)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
+        u32 intr_info = nr | INTR_INFO_VALID_MASK;
 
-        if (has_error_code)
+        if (has_error_code) {
                 vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
+                intr_info |= INTR_INFO_DELIVER_CODE_MASK;
+        }
 
         if (vcpu->arch.rmode.active) {
                 vmx->rmode.irq.pending = true;
                 vmx->rmode.irq.vector = nr;
                 vmx->rmode.irq.rip = kvm_rip_read(vcpu);
-                if (nr == BP_VECTOR)
+                if (nr == BP_VECTOR || nr == OF_VECTOR)
                         vmx->rmode.irq.rip++;
-                vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
-                             nr | INTR_TYPE_SOFT_INTR
-                             | (has_error_code ? INTR_INFO_DELIVER_CODE_MASK : 0)
-                             | INTR_INFO_VALID_MASK);
+                intr_info |= INTR_TYPE_SOFT_INTR;
+                vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
                 vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
                 kvm_rip_write(vcpu, vmx->rmode.irq.rip - 1);
                 return;
         }
 
-        vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
-                     nr | INTR_TYPE_EXCEPTION
-                     | (has_error_code ? INTR_INFO_DELIVER_CODE_MASK : 0)
-                     | INTR_INFO_VALID_MASK);
+        if (nr == BP_VECTOR || nr == OF_VECTOR) {
+                vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, 1);
+                intr_info |= INTR_TYPE_SOFT_EXCEPTION;
+        } else
+                intr_info |= INTR_TYPE_HARD_EXCEPTION;
+
+        vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
 }
 
 static bool vmx_exception_injected(struct kvm_vcpu *vcpu)
@@ -2650,7 +2654,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         }
 
         if ((intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK)) ==
-            (INTR_TYPE_EXCEPTION | 1)) {
+            (INTR_TYPE_HARD_EXCEPTION | 1)) {
                 kvm_run->exit_reason = KVM_EXIT_DEBUG;
                 return 0;
         }
@@ -3238,7 +3242,8 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
                         vmx->vcpu.arch.nmi_injected = false;
         }
         kvm_clear_exception_queue(&vmx->vcpu);
-        if (idtv_info_valid && type == INTR_TYPE_EXCEPTION) {
+        if (idtv_info_valid && (type == INTR_TYPE_HARD_EXCEPTION ||
+                                type == INTR_TYPE_SOFT_EXCEPTION)) {
                 if (idt_vectoring_info & VECTORING_INFO_DELIVER_CODE_MASK) {
                         error = vmcs_read32(IDT_VECTORING_ERROR_CODE);
                         kvm_queue_exception_e(&vmx->vcpu, vector, error);