[PATCH v2 3/3] virt: acrn: Introduce interface to fetch platform info from the hypervisor

[Fei Li]

From: Shuo Liu <shuo.a.liu@xxxxxxxxx>

The ACRN hypervisor configures the guest VMs information statically and
builds guest VM configurations within the hypervisor. There are also
some hardware information are stored in the hypervisor in boot stage.
The ACRN userspace needs platform information to do the orchestration.

The HSM provides the following interface for the ACRN userspace to fetch
platform info:
 - ACRN_IOCTL_GET_PLATFORM_INFO
   Exchange the basic information by a struct acrn_platform_info. If the
   ACRN userspace provides a userspace buffer (whose vma filled in
   vm_configs_addr), the HSM creates a bounce buffer (kmalloced for
   continuous memory region) to fetch VM configurations data from the
   hypervisor.

Signed-off-by: Shuo Liu <shuo.a.liu@xxxxxxxxx>
Signed-off-by: Fei Li <fei1.li@xxxxxxxxx>
---
 drivers/virt/acrn/hsm.c       | 53 +++++++++++++++++++++++++++++++++++
 drivers/virt/acrn/hypercall.h | 12 ++++++++
 include/uapi/linux/acrn.h     | 44 +++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+)

diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
index 5419794fccf1..eb824a1a86a0 100644
--- a/drivers/virt/acrn/hsm.c
+++ b/drivers/virt/acrn/hsm.c
@@ -108,6 +108,7 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
 			   unsigned long ioctl_param)
 {
 	struct acrn_vm *vm = filp->private_data;
+	struct acrn_platform_info *plat_info;
 	struct acrn_vm_creation *vm_param;
 	struct acrn_vcpu_regs *cpu_regs;
 	struct acrn_ioreq_notify notify;
@@ -115,9 +116,12 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
 	struct acrn_ioeventfd ioeventfd;
 	struct acrn_vm_memmap memmap;
 	struct acrn_mmiodev *mmiodev;
+	void __user *vm_configs_user;
 	struct acrn_msi_entry *msi;
 	struct acrn_pcidev *pcidev;
 	struct acrn_irqfd irqfd;
+	void *vm_configs = NULL;
+	size_t vm_configs_size;
 	struct acrn_vdev *vdev;
 	struct page *page;
 	u64 cstate_cmd;
@@ -130,6 +134,55 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
 	}
 
 	switch (cmd) {
+	case ACRN_IOCTL_GET_PLATFORM_INFO:
+		plat_info = memdup_user((void __user *)ioctl_param,
+					sizeof(struct acrn_platform_info));
+		if (IS_ERR(plat_info))
+			return PTR_ERR(plat_info);
+
+		for (i = 0; i < ARRAY_SIZE(plat_info->sw.reserved); i++)
+			if (plat_info->sw.reserved[i])
+				return -EINVAL;
+
+		for (i = 0; i < ARRAY_SIZE(plat_info->hw.reserved); i++)
+			if (plat_info->hw.reserved[i])
+				return -EINVAL;
+
+		vm_configs_size = plat_info->sw.vm_config_size *
+						plat_info->sw.max_vms;
+		if (plat_info->sw.vm_configs_addr && vm_configs_size) {
+			vm_configs_user = plat_info->sw.vm_configs_addr;
+			vm_configs = kzalloc(vm_configs_size, GFP_KERNEL);
+			if (IS_ERR(vm_configs)) {
+				kfree(plat_info);
+				return PTR_ERR(vm_configs);
+			}
+			plat_info->sw.vm_configs_addr =
+					(void __user *)virt_to_phys(vm_configs);
+		}
+
+		ret = hcall_get_platform_info(virt_to_phys(plat_info));
+		if (ret < 0) {
+			kfree(vm_configs);
+			kfree(plat_info);
+			dev_dbg(acrn_dev.this_device,
+				"Failed to get info of VM %u!\n", vm->vmid);
+			break;
+		}
+
+		if (vm_configs) {
+			if (copy_to_user(vm_configs_user, vm_configs,
+					 vm_configs_size))
+				ret = -EFAULT;
+			plat_info->sw.vm_configs_addr = vm_configs_user;
+		}
+		if (!ret && copy_to_user((void __user *)ioctl_param, plat_info,
+					 sizeof(*plat_info)))
+			ret = -EFAULT;
+
+		kfree(vm_configs);
+		kfree(plat_info);
+		break;
 	case ACRN_IOCTL_CREATE_VM:
 		vm_param = memdup_user((void __user *)ioctl_param,
 				       sizeof(struct acrn_vm_creation));
diff --git a/drivers/virt/acrn/hypercall.h b/drivers/virt/acrn/hypercall.h
index 71d300821a18..440e204d731a 100644
--- a/drivers/virt/acrn/hypercall.h
+++ b/drivers/virt/acrn/hypercall.h
@@ -15,6 +15,7 @@
 
 #define HC_ID_GEN_BASE			0x0UL
 #define HC_SOS_REMOVE_CPU		_HC_ID(HC_ID, HC_ID_GEN_BASE + 0x01)
+#define HC_GET_PLATFORM_INFO		_HC_ID(HC_ID, HC_ID_GEN_BASE + 0x03)
 
 #define HC_ID_VM_BASE			0x10UL
 #define HC_CREATE_VM			_HC_ID(HC_ID, HC_ID_VM_BASE + 0x00)
@@ -60,6 +61,17 @@ static inline long hcall_sos_remove_cpu(u64 cpu)
 	return acrn_hypercall1(HC_SOS_REMOVE_CPU, cpu);
 }
 
+/**
+ * hcall_get_platform_info() - Get platform information from the hypervisor
+ * @platform_info: Service VM GPA of the &struct acrn_platform_info
+ *
+ * Return: 0 on success, <0 on failure
+ */
+static inline long hcall_get_platform_info(u64 platform_info)
+{
+	return acrn_hypercall1(HC_GET_PLATFORM_INFO, platform_info);
+}
+
 /**
  * hcall_create_vm() - Create a User VM
  * @vminfo:	Service VM GPA of info of User VM creation
diff --git a/include/uapi/linux/acrn.h b/include/uapi/linux/acrn.h
index 1408d1063339..2675d17bc803 100644
--- a/include/uapi/linux/acrn.h
+++ b/include/uapi/linux/acrn.h
@@ -580,12 +580,56 @@ struct acrn_irqfd {
 	struct acrn_msi_entry	msi;
 };
 
+#define ACRN_PLATFORM_LAPIC_IDS_MAX	64
+/**
+ * struct acrn_platform_info - Information of a platform from hypervisor
+ * @hw.cpu_num:			Physical CPU number of the platform
+ * @hw.version:			Version of this structure
+ * @hw.l2_cat_shift:		Order of the number of threads sharing L2 cache
+ * @hw.l3_cat_shift:		Order of the number of threads sharing L3 cache
+ * @hw.lapic_ids:		IDs of LAPICs of all threads
+ * @hw.reserved:		Reserved for alignment and should be 0
+ * @sw.max_vcpus_per_vm:	Maximum number of vCPU of a VM
+ * @sw.max_vms:			Maximum number of VM
+ * @sw.vm_config_size:		Size of configuration of a VM
+ * @sw.vm_configss_addr:	Memory address which user space provided to
+ *				store the VM configurations
+ * @sw.max_kata_containers:	Maximum number of VM for Kata containers
+ * @sw.reserved:		Reserved for alignment and should be 0
+ *
+ * If vm_configs_addr is provided, the driver uses a bounce buffer (kmalloced
+ * for continuous memory region) to fetch VM configurations data from the
+ * hypervisor.
+ */
+struct acrn_platform_info {
+	struct {
+		__u16	cpu_num;
+		__u16	version;
+		__u32	l2_cat_shift;
+		__u32	l3_cat_shift;
+		__u8	lapic_ids[ACRN_PLATFORM_LAPIC_IDS_MAX];
+		__u8	reserved[52];
+	} hw;
+
+	struct {
+		__u16	max_vcpus_per_vm;
+		__u16	max_vms;
+		__u32	vm_config_size;
+		void	__user *vm_configs_addr;
+		__u64	max_kata_containers;
+		__u8	reserved[104];
+	} sw;
+};
+
 /* The ioctl type, documented in ioctl-number.rst */
 #define ACRN_IOCTL_TYPE			0xA2
 
 /*
  * Common IOCTL IDs definition for ACRN userspace
  */
+#define ACRN_IOCTL_GET_PLATFORM_INFO	\
+	_IOR(ACRN_IOCTL_TYPE, 0x03, struct acrn_platform_info)
+
 #define ACRN_IOCTL_CREATE_VM		\
 	_IOWR(ACRN_IOCTL_TYPE, 0x10, struct acrn_vm_creation)
 #define ACRN_IOCTL_DESTROY_VM		\
-- 
2.25.1