hv:Simplify for-loop when walk through the vcpu

-- Not return NULL for vcpu_from_vid
  We have replaced dynamic memory with static memory for vcpu,
  then if vcpu_id is valid, this API should not return NULL.
-- Simplify the for-loop when walk through the vcpu

Tracked-On: #861
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Reviewed-by: Li, Fei1 <fei1.li@intel.com>
Reviewed-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/guest/guest.c

@@ -38,12 +38,12 @@ uint64_t vcpumask2pcpumask(struct vm *vm, uint64_t vdmask)
 	uint64_t dmask = 0UL;
 	struct vcpu *vcpu;
 
-	for (vcpu_id = ffs64(vdmask); vcpu_id != INVALID_BIT_INDEX;
+	for (vcpu_id = 0U; vcpu_id < vm->hw.created_vcpus; vcpu_id++) {
-		vcpu_id = ffs64(vdmask)) {
+		if (vdmask & (1U << vcpu_id)) {
-		bitmap_clear_lock(vcpu_id, &vdmask);
 			vcpu = vcpu_from_vid(vm, vcpu_id);
 			bitmap_set_lock(vcpu->pcpu_id, &dmask);
 		}
+	}
 
 	return dmask;
 }

hypervisor/arch/x86/guest/vlapic.c

@@ -1020,10 +1020,8 @@ vlapic_calcdest(struct vm *vm, uint64_t *dmask, uint32_t dest,
 		 */
 		*dmask = 0UL;
 		amask = vm_active_cpus(vm);
-		for (vcpu_id = ffs64(amask); vcpu_id != INVALID_BIT_INDEX;
+		for (vcpu_id = 0U; vcpu_id < vm->hw.created_vcpus; vcpu_id++) {
-			vcpu_id = ffs64(amask)) {
+			if (amask & (1U << vcpu_id)) {
-			bitmap_clear_lock(vcpu_id, &amask);
-
 				vlapic = vm_lapic_from_vcpu_id(vm, vcpu_id);
 				dfr = vlapic->apic_page.dfr.v;
 				ldr = vlapic->apic_page.ldr.v;
@@ -1069,6 +1067,7 @@ vlapic_calcdest(struct vm *vm, uint64_t *dmask, uint32_t dest,
 					}
 				}
 			}
+		}
 
 		if (lowprio && (target != NULL)) {
 			bitmap_set_lock(target->vcpu->vcpu_id, dmask);
@@ -1189,13 +1188,9 @@ vlapic_icrlo_write_handler(struct acrn_vlapic *vlapic)
 		break;
 	}
 
-	for (vcpu_id = ffs64(dmask); vcpu_id != INVALID_BIT_INDEX;
+	for (vcpu_id = 0U; vcpu_id < vlapic->vm->hw.created_vcpus; vcpu_id++) {
-		vcpu_id = ffs64(dmask)) {
+		if (dmask & (1U << vcpu_id)) {
-		bitmap_clear_lock(vcpu_id, &dmask);
 			target_vcpu = vcpu_from_vid(vlapic->vm, vcpu_id);
-		if (target_vcpu == NULL) {
-			continue;
-		}
 
 			if (mode == APIC_DELMODE_FIXED) {
 				vlapic_set_intr(target_vcpu, vec,
@@ -1251,6 +1246,7 @@ vlapic_icrlo_write_handler(struct acrn_vlapic *vlapic)
 				pr_err("Unhandled icrlo write with mode %u\n", mode);
 			}
 		}
+	}
 
 	return 0;	/* handled completely in the kernel */
 }
@@ -1723,14 +1719,10 @@ vlapic_deliver_intr(struct vm *vm, bool level, uint32_t dest, bool phys,
 	 */
 	vlapic_calcdest(vm, &dmask, dest, phys, lowprio);
 
-	for (vcpu_id = ffs64(dmask); vcpu_id != INVALID_BIT_INDEX;
+	for (vcpu_id = 0U; vcpu_id < vm->hw.created_vcpus; vcpu_id++) {
-		vcpu_id = ffs64(dmask)) {
 		struct acrn_vlapic *vlapic;
-		bitmap_clear_lock(vcpu_id, &dmask);
+		if (dmask & (1U << vcpu_id)) {
 			target_vcpu = vcpu_from_vid(vm, vcpu_id);
-		if (target_vcpu == NULL) {
-			return;
-		}
 
 			/* only make request when vlapic enabled */
 			vlapic = vcpu_vlapic(target_vcpu);
@@ -1743,6 +1735,7 @@ vlapic_deliver_intr(struct vm *vm, bool level, uint32_t dest, bool phys,
 			}
 		}
 	}
+}
 
 bool
 vlapic_enabled(struct acrn_vlapic *vlapic)
@@ -1875,15 +1868,15 @@ vlapic_set_local_intr(struct vm *vm, uint16_t vcpu_id_arg, uint32_t vector)
 		bitmap_set_lock(vcpu_id, &dmask);
 	}
 	error = 0;
-	for (vcpu_id = ffs64(dmask); vcpu_id != INVALID_BIT_INDEX;
+	for (vcpu_id = 0U; vcpu_id < vm->hw.created_vcpus; vcpu_id++) {
-		vcpu_id = ffs64(dmask)) {
+		if (dmask & (1U << vcpu_id)) {
-		bitmap_clear_lock(vcpu_id, &dmask);
 			vlapic = vm_lapic_from_vcpu_id(vm, vcpu_id);
 			error = vlapic_trigger_lvt(vlapic, vector);
 			if (error != 0) {
 				break;
 			}
 		}
+	}
 
 	return error;
 }

hypervisor/common/hypercall.c

@@ -319,12 +319,12 @@ int32_t hcall_set_vcpu_regs(struct vm *vm, uint16_t vmid, uint64_t param)
 		return -1;
 	}
 
-	vcpu = vcpu_from_vid(target_vm, vcpu_regs.vcpu_id);
+	if (vcpu_regs.vcpu_id >= CONFIG_MAX_VCPUS_PER_VM) {
-	if (vcpu == NULL) {
 		pr_err("%s: invalid vcpu_id for set_vcpu_regs\n", __func__);
 		return -1;
 	}
 
+	vcpu = vcpu_from_vid(target_vm, vcpu_regs.vcpu_id);
 	set_vcpu_regs(vcpu, &(vcpu_regs.vcpu_regs));
 
 	return 0;
@@ -437,13 +437,13 @@ int32_t hcall_notify_ioreq_finish(uint16_t vmid, uint16_t vcpu_id)
 	dev_dbg(ACRN_DBG_HYCALL, "[%d] NOTIFY_FINISH for vcpu %d",
 			vmid, vcpu_id);
 
-	vcpu = vcpu_from_vid(target_vm, vcpu_id);
+	if (vcpu_id >= CONFIG_MAX_VCPUS_PER_VM) {
-	if (vcpu == NULL) {
 		pr_err("%s, failed to get VCPU %d context from VM %d\n",
 			__func__, vcpu_id, target_vm->vm_id);
 		return -EINVAL;
 	}
 
+	vcpu = vcpu_from_vid(target_vm, vcpu_id);
 	emulate_io_post(vcpu);
 
 	return 0;

hypervisor/debug/shell.c

@@ -651,13 +651,13 @@ static int shell_vcpu_dumpreg(int argc, char **argv)
 		goto out;
 	}
 
-	vcpu = vcpu_from_vid(vm, vcpu_id);
+	if (vcpu_id >= CONFIG_MAX_VCPUS_PER_VM) {
-	if (vcpu == NULL) {
 		shell_puts("No vcpu found in the input <vm_id, vcpu_id>\r\n");
 		status = -EINVAL;
 		goto out;
 	}
 
+	vcpu = vcpu_from_vid(vm, vcpu_id);
 	dump.vcpu = vcpu;
 	dump.str = shell_log_buf;
 	dump.str_max = CPU_PAGE_SIZE;

hypervisor/include/arch/x86/guest/vm.h

@@ -199,6 +199,9 @@ static inline bool is_vm0(struct vm *vm)
 	return (vm->vm_id) == 0U;
 }
 
+/*
+ * @pre vcpu_id < CONFIG_MAX_VCPUS_PER_VM
+ */
 static inline struct vcpu *vcpu_from_vid(struct vm *vm, uint16_t vcpu_id)
 {
 	uint16_t i;
@@ -206,12 +209,11 @@ static inline struct vcpu *vcpu_from_vid(struct vm *vm, uint16_t vcpu_id)
 
 	foreach_vcpu(i, vm, vcpu) {
 		if (vcpu->vcpu_id == vcpu_id) {
+			break;
+		}
+	}
 	return vcpu;
 }
-	}
-
-	return NULL;
-}
 
 static inline struct vcpu *vcpu_from_pid(struct vm *vm, uint16_t pcpu_id)
 {