hv: pio_region: add hypercalls to support pio device pass through

Add two hypercalls HC_ASSIGN_PIO_REGION and HC_DEASSIGN_PIO_REGION to
support PIO device pass through for post-launched VM.

Add has_direct_pio_access function to check the pio access state of VM
before allow/deny guest pio access.

Align querying, setting and clearing interfaces of VM io.bitmap with
general bitmap operation function.

Tracked-On: #8635
Signed-off-by: Yichong Tang <yichong.tang@intel.com>
Reviewed-by: Junjie Mao <junjie.mao@intel.com>

hypervisor/arch/x86/guest/vmcall.c

@@ -82,6 +82,10 @@ static const struct hc_dispatch hc_dispatch_table[] = {
 		.handler = hcall_add_vdev},
 	[HC_IDX(HC_REMOVE_VDEV)] = {
 		.handler = hcall_remove_vdev},
+	[HC_IDX(HC_ASSIGN_PIO_REGION)] = {
+		.handler = hcall_assign_pio_region},
+	[HC_IDX(HC_DEASSIGN_PIO_REGION)] = {
+		.handler = hcall_deassign_pio_region},
 	[HC_IDX(HC_SET_PTDEV_INTR_INFO)] = {
 		.handler = hcall_set_ptdev_intr_info},
 	[HC_IDX(HC_RESET_PTDEV_INTR_INFO)] = {

hypervisor/arch/x86/guest/vmx_io.c

@@ -204,7 +204,7 @@ void allow_guest_pio_access(struct acrn_vm *vm, uint16_t port_address,
 
 	b = (uint32_t *)vm->arch_vm.io_bitmap;
 	for (i = 0U; i < nbytes; i++) {
-		b[address >> 5U] &= ~(1U << (address & 0x1fU));
+		bitmap32_clear_nolock(address & 0x1fU, &b[address >> 5U]);
 		address++;
 	}
 }
@@ -218,7 +218,35 @@ void deny_guest_pio_access(struct acrn_vm *vm, uint16_t port_address,
 
 	b = (uint32_t *)vm->arch_vm.io_bitmap;
 	for (i = 0U; i < nbytes; i++) {
-		b[address >> 5U] |= (1U << (address & 0x1fU));
+		bitmap32_set_nolock(address & 0x1fU, &b[address >> 5U]);
 		address++;
 	}
 }
+
+/**
+ * @brief Check if a VM has full access to a port I/O range
+ *
+ * This API check if given \p vm has direct access to the port I/O space
+ * starting from \p port_address to \p port_address + \p nbytes - 1.
+ *
+ * @param vm The VM whose port I/O access permissions is to be checked
+ * @param port_address The start address of the port I/O range
+ * @param nbytes The size of the range, in bytes
+ */
+bool has_direct_pio_access(struct acrn_vm *vm, uint16_t port_address, uint32_t nbytes)
+{
+	uint16_t address = port_address;
+	uint32_t *b;
+	uint32_t i;
+	bool ret = true;
+
+	b = (uint32_t *)vm->arch_vm.io_bitmap;
+	for (i = 0U; i < nbytes; i++) {
+		if (bitmap32_test(address & 0x1fU, &b[address >> 5U])) {
+			ret = false;
+			break;
+		}
+		address++;
+	}
+	return ret;
+}

hypervisor/common/hypercall.c

@@ -1354,3 +1354,75 @@ int32_t hcall_remove_vdev(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm, __u
 	}
 	return ret;
 }
+
+/**
+ * @brief Assign PIO device resource to a VM.
+ *
+ * @param vcpu Pointer to vCPU that initiates the hypercall
+ * @param target_vm Pointer to target VM data structure
+ * @param param2 guest physical address. This gpa points to data structure of
+ *              acrn_pio_region including assign PIO resource info
+ *
+ * @pre is_service_vm(vcpu->vm)
+ * @return 0 on success, non-zero on error.
+ */
+int32_t hcall_assign_pio_region(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm,
+		__unused uint64_t param1, uint64_t param2)
+{
+	struct acrn_vm *vm = vcpu->vm;
+	int32_t ret = -EINVAL;
+	struct acrn_pio_region pio_region;
+
+	/* We should only assign a device to a post-launched VM at creating time for safety, not runtime or other cases*/
+	if (is_created_vm(target_vm)) {
+		if (copy_from_gpa(vm, &pio_region, param2, sizeof(pio_region)) == 0) {
+			if (has_direct_pio_access(vm, pio_region.res.port_address, pio_region.res.size)) {
+				deny_guest_pio_access(vm, pio_region.res.port_address, pio_region.res.size);
+				allow_guest_pio_access(target_vm, pio_region.res.port_address, pio_region.res.size);
+				ret = 0;
+			} else {
+				pr_err("vm[%d] %s failed: pio region not fully accessible for vm[%d].\n",target_vm->vm_id, __func__, vm->vm_id);
+			}
+		}
+	} else {
+		pr_err("vm[%d] %s failed: target vm not created.\n",target_vm->vm_id, __func__);
+	}
+
+	return ret;
+}
+
+/**
+ * @brief Deassign PIO device resource from a VM.
+ *
+ * @param vcpu Pointer to vCPU that initiates the hypercall
+ * @param target_vm Pointer to target VM data structure
+ * @param param2 guest physical address. This gpa points to data structure of
+ *              acrn_pio_region including deassign PIO device info
+ *
+ * @pre is_service_vm(vcpu->vm)
+ * @return 0 on success, non-zero on error.
+ */
+int32_t hcall_deassign_pio_region(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm,
+		__unused uint64_t param1, uint64_t param2)
+{
+	struct acrn_vm *vm = vcpu->vm;
+	int32_t ret = -EINVAL;
+	struct acrn_pio_region pio_region;
+
+	/* We should only de-assign a device from a post-launched VM at creating/shutdown/reset time */
+	if ((is_paused_vm(target_vm) || is_created_vm(target_vm))) {
+		if (copy_from_gpa(vm, &pio_region, param2, sizeof(pio_region)) == 0) {
+			if (has_direct_pio_access(target_vm, pio_region.res.port_address, pio_region.res.size)) {
+				deny_guest_pio_access(target_vm, pio_region.res.port_address, pio_region.res.size);
+				allow_guest_pio_access(vm, pio_region.res.port_address, pio_region.res.size);
+				ret = 0;
+			} else {
+				pr_err("vm[%d] %s failed: pio region not fully accessible for vm[%d].\n",vm->vm_id, __func__, target_vm->vm_id);
+			}
+		}
+	} else {
+		pr_err("vm[%d] %s failed: target vm not created or not paused.\n",target_vm->vm_id, __func__);
+	}
+
+	return ret;
+}

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

@@ -80,6 +80,18 @@ void   allow_guest_pio_access(struct acrn_vm *vm, uint16_t port_address, uint32_
  */
 void deny_guest_pio_access(struct acrn_vm *vm, uint16_t port_address, uint32_t nbytes);
 
+/**
+ * @brief Check if a VM has full access to a port I/O range
+ *
+ * This API check if given \p vm has direct access to the port I/O space
+ * starting from \p port_address to \p port_address + \p nbytes - 1.
+ *
+ * @param vm The VM whose port I/O access permissions is to be checked
+ * @param port_address The start address of the port I/O range
+ * @param nbytes The size of the range, in bytes
+ */
+bool has_direct_pio_access(struct acrn_vm *vm, uint16_t port_address, uint32_t nbytes);
+
 /**
  * @brief Fire HSM interrupt to Service VM
  */

hypervisor/include/common/hypercall.h

@@ -346,6 +346,34 @@ int32_t hcall_add_vdev(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm, uint64
  */
 int32_t hcall_remove_vdev(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm, uint64_t param1, uint64_t param2);
 
+/**
+ * @brief Assign PIO device resource to VM.
+ *
+ * @param vcpu Pointer to vCPU that initiates the hypercall
+ * @param target_vm Pointer to target VM data structure
+ * @param param1 not used
+ * @param param2 guest physical address. This gpa points to data structure of
+ *              acrn_mmiores including assign PIO device resource info
+ *
+ * @pre is_service_vm(vcpu->vm)
+ * @return 0 on success, non-zero on error.
+ */
+int32_t hcall_assign_pio_region(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm, uint64_t param1, uint64_t param2);
+
+/**
+ * @brief Deassign PIO device resource from VM.
+ *
+ * @param vcpu Pointer to vCPU that initiates the hypercall
+ * @param target_vm Pointer to target VM data structure
+ * @param param1 not used
+ * @param param2 guest physical address. This gpa points to data structure of
+ *              acrn_mmiores including assign PIO device resource info
+ *
+ * @pre is_service_vm(vcpu->vm)
+ * @return 0 on success, non-zero on error.
+ */
+int32_t hcall_deassign_pio_region(struct acrn_vcpu *vcpu, struct acrn_vm *target_vm, uint64_t param1, uint64_t param2);
+
 /**
  * @brief Set interrupt mapping info of ptdev.
  *

hypervisor/include/public/acrn_common.h

@@ -707,6 +707,19 @@ struct acrn_mmiodev {
 	} res[MMIODEV_RES_NUM];
 };
 
+/**
+ * @brief Info to assign or deassign a PIO device for a VM
+ */
+struct acrn_pio_region {
+	char name[8];
+	struct acrn_piores {
+		/** the io port address for PIO device */
+		uint16_t port_address;
+		/** the size of the io port for the PIO resource */
+		uint16_t size;
+	} res;
+};
+
 /**
  * @brief Info to create or destroy a virtual PCI or legacy device for a VM
  *

hypervisor/include/public/acrn_hv_defs.h

@@ -74,6 +74,8 @@
 #define HC_DEASSIGN_MMIODEV         BASE_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x08UL)
 #define HC_ADD_VDEV                 BASE_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x09UL)
 #define HC_REMOVE_VDEV              BASE_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x0AUL)
+#define HC_ASSIGN_PIO_REGION        BASE_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x0BUL)
+#define HC_DEASSIGN_PIO_REGION      BASE_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x0CUL)
 
 /* DEBUG */
 #define HC_ID_DBG_BASE              0x60UL