vmexit: refine vmexit loop

- move vmexit handling into vmexit_handler
- add error handling, failure will inject #GP

Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

Author: JasonChenCJ

hypervisor/arch/x86/vmexit.c

@@ -156,10 +156,16 @@ static const struct vm_exit_dispatch dispatch_table[] = {
 		.need_exit_qualification = 1}
 };
 
-struct vm_exit_dispatch *vmexit_handler(struct vcpu *vcpu)
+int vmexit_handler(struct vcpu *vcpu)
 {
 	struct vm_exit_dispatch *dispatch = HV_NULL;
 	uint16_t basic_exit_reason;
+	int ret;
+
+	if ((int)get_cpu_id() != vcpu->pcpu_id) {
+		pr_fatal("vcpu is not running on its pcpu!");
+		return -EINVAL;
+	}
 
 	/* Obtain interrupt info */
 	vcpu->arch_vcpu.idt_vectoring_info =
@@ -190,8 +196,19 @@ struct vm_exit_dispatch *vmexit_handler(struct vcpu *vcpu)
 	/* Update current vcpu in VM that caused vm exit */
 	vcpu->vm->current_vcpu = vcpu;
 
-	/* Return pointer to exit dispatch entry */
-	return dispatch;
+	/* exit dispatch handling */
+	if (basic_exit_reason == VMX_EXIT_REASON_EXTERNAL_INTERRUPT) {
+		/* Handling external_interrupt
+		 * should disable intr
+		 */
+		ret = dispatch->handler(vcpu);
+	} else {
+		CPU_IRQ_ENABLE();
+		ret = dispatch->handler(vcpu);
+		CPU_IRQ_DISABLE();
+	}
+
+	return ret;
 }
 
 static int unhandled_vmexit_handler(__unused struct vcpu *vcpu)

hypervisor/common/hv_main.c

@@ -53,7 +53,6 @@ void vcpu_thread(struct vcpu *vcpu)
 	uint64_t vmexit_begin = 0, vmexit_end = 0;
 	uint16_t basic_exit_reason = 0;
 	uint64_t tsc_aux_hyp_cpu = vcpu->pcpu_id;
-	struct vm_exit_dispatch *vmexit_hdlr;
 	int ret = 0;
 
 	/* If vcpu is not launched, we need to do init_vmcs first */
@@ -97,7 +96,11 @@ void vcpu_thread(struct vcpu *vcpu)
 		}
 
 		ret = start_vcpu(vcpu);
-		ASSERT(ret == 0, "vcpu resume failed");
+		if (ret != 0) {
+			pr_fatal("vcpu resume failed");
+			pause_vcpu(vcpu, VCPU_ZOMBIE);
+			continue;
+		}
 
 		vmexit_begin = rdtsc();
 
@@ -106,28 +109,21 @@ void vcpu_thread(struct vcpu *vcpu)
 		CPU_MSR_READ(MSR_IA32_TSC_AUX, &vcpu->msr_tsc_aux_guest);
 		/* Restore native TSC_AUX */
 		CPU_MSR_WRITE(MSR_IA32_TSC_AUX, tsc_aux_hyp_cpu);
-		ASSERT((int)get_cpu_id() == vcpu->pcpu_id, "");
 
 		/* Dispatch handler */
-		vmexit_hdlr = vmexit_handler(vcpu);
-		ASSERT(vmexit_hdlr != 0,
-				"Unable to dispatch VM exit handler!");
+		ret = vmexit_handler(vcpu);
+		if (ret < 0) {
+			pr_fatal("dispatch VM exit handler failed for reason"
+				" %d, ret = %d!",
+				vcpu->arch_vcpu.exit_reason & 0xFFFF, ret);
+			vcpu_inject_gp(vcpu);
+			continue;
+		}
 
 		basic_exit_reason = vcpu->arch_vcpu.exit_reason & 0xFFFF;
 		per_cpu(vmexit_cnt, vcpu->pcpu_id)[basic_exit_reason]++;
 		TRACE_2L(TRACE_VM_EXIT, basic_exit_reason,
 		vcpu->arch_vcpu.contexts[vcpu->arch_vcpu.cur_context].rip);
-
-		if (basic_exit_reason == VMX_EXIT_REASON_EXTERNAL_INTERRUPT) {
-			/* Handling external_interrupt
-			 * should disable intr
-			 */
-			vmexit_hdlr->handler(vcpu);
-		} else {
-			CPU_IRQ_ENABLE();
-			vmexit_hdlr->handler(vcpu);
-			CPU_IRQ_DISABLE();
-		}
 	} while (1);
 }
 

hypervisor/include/arch/x86/vmexit.h

@@ -36,7 +36,7 @@ struct vm_exit_dispatch {
 	uint32_t need_exit_qualification;
 };
 
-struct vm_exit_dispatch *vmexit_handler(struct vcpu *vcpu);
+int vmexit_handler(struct vcpu *vcpu);
 int vmcall_vmexit_handler(struct vcpu *vcpu);
 int cpuid_vmexit_handler(struct vcpu *vcpu);
 int cr_access_vmexit_handler(struct vcpu *vcpu);