hv: support asyncio request

Current IO emulation is synchronous. The user VM need to wait for the
completion of the the I/O request before return. But Virtio Spec
introduces introduces asynchronous IO with a new register in MMIO/PIO
space named NOTIFY, to be used for FE driver to notify BE driver, ACRN
hypervisor can emulate this register by sending a notification to vCPU
in Service VM side. This way, FE side can resume to work without waiting
for the full completion of BE side response.

Tracked-On: #8209
Signed-off-by: Conghui <conghui.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/guest/vm.c

@@ -758,6 +758,7 @@ int32_t create_vm(uint16_t vm_id, uint64_t pcpu_bitmap, struct acrn_vm_config *v
 			/* Populate return VM handle */
 			*rtn_vm = vm;
 			vm->sw.io_shared_page = NULL;
+			vm->sw.asyncio_sbuf = NULL;
 			if ((vm_config->load_order == POST_LAUNCHED_VM)
 				&& ((vm_config->guest_flags & GUEST_FLAG_IO_COMPLETION_POLLING) != 0U)) {
 				/* enable IO completion polling mode per its guest flags in vm_config. */

hypervisor/common/sbuf.c

@@ -77,7 +77,7 @@ uint32_t sbuf_put(struct shared_buf *sbuf, uint8_t *data)
 	return ele_size;
 }
 
-int32_t sbuf_setup_common(__unused struct acrn_vm *vm, uint16_t cpu_id, uint32_t sbuf_id, uint64_t *hva)
+int32_t sbuf_setup_common(struct acrn_vm *vm, uint16_t cpu_id, uint32_t sbuf_id, uint64_t *hva)
 {
 	int32_t ret = 0;
 
@@ -88,6 +88,9 @@ int32_t sbuf_setup_common(__unused struct acrn_vm *vm, uint16_t cpu_id, uint32_t
 		case ACRN_SOCWATCH:
 			ret = sbuf_share_setup(cpu_id, sbuf_id, hva);
 			break;
+		case ACRN_ASYNCIO:
+			ret = init_asyncio(vm, hva);
+			break;
 		default:
 			pr_err("%s not support sbuf_id %d", __func__, sbuf_id);
 			ret = -1;

hypervisor/debug/sbuf.c

@@ -17,7 +17,7 @@
 
 int32_t sbuf_share_setup(uint16_t pcpu_id, uint32_t sbuf_id, uint64_t *hva)
 {
-	if ((pcpu_id >= get_pcpu_nums()) || (sbuf_id >= ACRN_SBUF_ID_MAX)) {
+	if ((pcpu_id >= get_pcpu_nums()) || (sbuf_id >= ACRN_SBUF_PER_PCPU_ID_MAX)) {
 		return -EINVAL;
 	}
 
@@ -33,7 +33,7 @@ void sbuf_reset(void)
 	uint16_t pcpu_id, sbuf_id;
 
 	for (pcpu_id = 0U; pcpu_id < get_pcpu_nums(); pcpu_id++) {
-		for (sbuf_id = 0U; sbuf_id < ACRN_SBUF_ID_MAX; sbuf_id++) {
+		for (sbuf_id = 0U; sbuf_id < ACRN_SBUF_PER_PCPU_ID_MAX; sbuf_id++) {
 			per_cpu(sbuf, pcpu_id)[sbuf_id] = 0U;
 		}
 	}

hypervisor/dm/io_req.c

@@ -177,6 +177,23 @@ void set_io_req_state(struct acrn_vm *vm, uint16_t vcpu_id, uint32_t state)
 	}
 }
 
+int init_asyncio(struct acrn_vm *vm, uint64_t *hva)
+{
+	struct shared_buf *sbuf = (struct shared_buf *)hva;
+	int ret = -1;
+
+	stac();
+	if (sbuf != NULL) {
+		if (sbuf->magic == SBUF_MAGIC) {
+			vm->sw.asyncio_sbuf = sbuf;
+			ret = 0;
+		}
+	}
+	clac();
+
+	return ret;
+}
+
 void set_hsm_notification_vector(uint32_t vector)
 {
 	acrn_hsm_notification_vector = vector;

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

@@ -69,6 +69,7 @@ struct vm_sw_info {
 	struct sw_module_info acpi_info;
 	/* HVA to IO shared page */
 	void *io_shared_page;
+	void *asyncio_sbuf;
 	/* If enable IO completion polling mode */
 	bool is_polling_ioreq;
 };

hypervisor/include/arch/x86/asm/per_cpu.h

@@ -25,7 +25,7 @@ struct per_cpu_region {
 	uint8_t vmxon_region[PAGE_SIZE];
 	void *vmcs_run;
 #ifdef HV_DEBUG
-	struct shared_buf *sbuf[ACRN_SBUF_ID_MAX];
+	struct shared_buf *sbuf[ACRN_SBUF_PER_PCPU_ID_MAX];
 	char logbuf[LOG_MESSAGE_MAX_SIZE];
 	uint32_t npk_log_ref;
 #endif

hypervisor/include/dm/io_req.h

@@ -291,6 +291,8 @@ void register_mmio_emulation_handler(struct acrn_vm *vm,
 void unregister_mmio_emulation_handler(struct acrn_vm *vm,
 					uint64_t start, uint64_t end);
 void deinit_emul_io(struct acrn_vm *vm);
+
+int init_asyncio(struct acrn_vm *vm, uint64_t *hva);
 /**
  * @}
  */

hypervisor/include/public/acrn_common.h

@@ -746,7 +746,9 @@ enum {
 	ACRN_HVLOG,
 	ACRN_SEP,
 	ACRN_SOCWATCH,
-	ACRN_SBUF_ID_MAX,
+	/* The sbuf with above ids are created each pcpu */
+	ACRN_SBUF_PER_PCPU_ID_MAX,
+	ACRN_ASYNCIO = 64,
 };
 
 /* Make sure sizeof(struct shared_buf) == SBUF_HEAD_SIZE */