virt: acrn: Introduce interfaces to query C-states and P-states allowed by hypervisor

The C-states and P-states data are used to support CPU power management.
The hypervisor controls C-states and P-states for a User VM.

ACRN userspace need to query the data from the hypervisor to build ACPI
tables for a User VM.

HSM provides ioctls for ACRN userspace to query C-states and P-states
data obtained from the hypervisor.

Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Yu Wang <yu1.wang@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Link: https://lore.kernel.org/r/20210207031040.49576-14-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/acrn/hsm.c

@@ -38,6 +38,67 @@ static int acrn_dev_open(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static int pmcmd_ioctl(u64 cmd, void __user *uptr)
+{
+	struct acrn_pstate_data *px_data;
+	struct acrn_cstate_data *cx_data;
+	u64 *pm_info;
+	int ret = 0;
+
+	switch (cmd & PMCMD_TYPE_MASK) {
+	case ACRN_PMCMD_GET_PX_CNT:
+	case ACRN_PMCMD_GET_CX_CNT:
+		pm_info = kmalloc(sizeof(u64), GFP_KERNEL);
+		if (!pm_info)
+			return -ENOMEM;
+
+		ret = hcall_get_cpu_state(cmd, virt_to_phys(pm_info));
+		if (ret < 0) {
+			kfree(pm_info);
+			break;
+		}
+
+		if (copy_to_user(uptr, pm_info, sizeof(u64)))
+			ret = -EFAULT;
+		kfree(pm_info);
+		break;
+	case ACRN_PMCMD_GET_PX_DATA:
+		px_data = kmalloc(sizeof(*px_data), GFP_KERNEL);
+		if (!px_data)
+			return -ENOMEM;
+
+		ret = hcall_get_cpu_state(cmd, virt_to_phys(px_data));
+		if (ret < 0) {
+			kfree(px_data);
+			break;
+		}
+
+		if (copy_to_user(uptr, px_data, sizeof(*px_data)))
+			ret = -EFAULT;
+		kfree(px_data);
+		break;
+	case ACRN_PMCMD_GET_CX_DATA:
+		cx_data = kmalloc(sizeof(*cx_data), GFP_KERNEL);
+		if (!cx_data)
+			return -ENOMEM;
+
+		ret = hcall_get_cpu_state(cmd, virt_to_phys(cx_data));
+		if (ret < 0) {
+			kfree(cx_data);
+			break;
+		}
+
+		if (copy_to_user(uptr, cx_data, sizeof(*cx_data)))
+			ret = -EFAULT;
+		kfree(cx_data);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
 /*
  * HSM relies on hypercall layer of the ACRN hypervisor to do the
  * sanity check against the input parameters.
@@ -54,6 +115,7 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
 	struct acrn_msi_entry *msi;
 	struct acrn_pcidev *pcidev;
 	struct page *page;
+	u64 cstate_cmd;
 	int i, ret = 0;
 
 	if (vm->vmid == ACRN_INVALID_VMID && cmd != ACRN_IOCTL_CREATE_VM) {
@@ -267,6 +329,13 @@ static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
 	case ACRN_IOCTL_CLEAR_VM_IOREQ:
 		acrn_ioreq_request_clear(vm);
 		break;
+	case ACRN_IOCTL_PM_GET_CPU_STATE:
+		if (copy_from_user(&cstate_cmd, (void *)ioctl_param,
+				   sizeof(cstate_cmd)))
+			return -EFAULT;
+
+		ret = pmcmd_ioctl(cstate_cmd, (void __user *)ioctl_param);
+		break;
 	default:
 		dev_dbg(acrn_dev.this_device, "Unknown IOCTL 0x%x!\n", cmd);
 		ret = -ENOTTY;

drivers/virt/acrn/hypercall.h

@@ -39,6 +39,9 @@
 #define HC_ASSIGN_PCIDEV		_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x05)
 #define HC_DEASSIGN_PCIDEV		_HC_ID(HC_ID, HC_ID_PCI_BASE + 0x06)
 
+#define HC_ID_PM_BASE			0x80UL
+#define HC_PM_GET_CPU_STATE		_HC_ID(HC_ID, HC_ID_PM_BASE + 0x00)
+
 /**
  * hcall_create_vm() - Create a User VM
  * @vminfo:	Service VM GPA of info of User VM creation
@@ -225,4 +228,13 @@ static inline long hcall_reset_ptdev_intr(u64 vmid, u64 irq)
 	return acrn_hypercall2(HC_RESET_PTDEV_INTR, vmid, irq);
 }
 
+/*
+ * hcall_get_cpu_state() - Get P-states and C-states info from the hypervisor
+ * @state:	Service VM GPA of buffer of P-states and C-states
+ */
+static inline long hcall_get_cpu_state(u64 cmd, u64 state)
+{
+	return acrn_hypercall2(HC_PM_GET_CPU_STATE, cmd, state);
+}
+
 #endif /* __ACRN_HSM_HYPERCALL_H */

include/uapi/linux/acrn.h

@@ -427,6 +427,58 @@ struct acrn_msi_entry {
 	__u64	msi_data;
 };
 
+struct acrn_acpi_generic_address {
+	__u8	space_id;
+	__u8	bit_width;
+	__u8	bit_offset;
+	__u8	access_size;
+	__u64	address;
+} __attribute__ ((__packed__));
+
+/**
+ * struct acrn_cstate_data - A C state package defined in ACPI
+ * @cx_reg:	Register of the C state object
+ * @type:	Type of the C state object
+ * @latency:	The worst-case latency to enter and exit this C state
+ * @power:	The average power consumption when in this C state
+ */
+struct acrn_cstate_data {
+	struct acrn_acpi_generic_address	cx_reg;
+	__u8					type;
+	__u32					latency;
+	__u64					power;
+};
+
+/**
+ * struct acrn_pstate_data - A P state package defined in ACPI
+ * @core_frequency:	CPU frequency (in MHz).
+ * @power:		Power dissipation (in milliwatts).
+ * @transition_latency:	The worst-case latency in microseconds that CPU is
+ * 			unavailable during a transition from any P state to
+ * 			this P state.
+ * @bus_master_latency:	The worst-case latency in microseconds that Bus Masters
+ * 			are prevented from accessing memory during a transition
+ * 			from any P state to this P state.
+ * @control:		The value to be written to Performance Control Register
+ * @status:		Transition status.
+ */
+struct acrn_pstate_data {
+	__u64	core_frequency;
+	__u64	power;
+	__u64	transition_latency;
+	__u64	bus_master_latency;
+	__u64	control;
+	__u64	status;
+};
+
+#define PMCMD_TYPE_MASK		0x000000ff
+enum acrn_pm_cmd_type {
+	ACRN_PMCMD_GET_PX_CNT,
+	ACRN_PMCMD_GET_PX_DATA,
+	ACRN_PMCMD_GET_CX_CNT,
+	ACRN_PMCMD_GET_CX_DATA,
+};
+
 /* The ioctl type, documented in ioctl-number.rst */
 #define ACRN_IOCTL_TYPE			0xA2
 
@@ -478,4 +530,7 @@ struct acrn_msi_entry {
 #define ACRN_IOCTL_DEASSIGN_PCIDEV	\
 	_IOW(ACRN_IOCTL_TYPE, 0x56, struct acrn_pcidev)
 
+#define ACRN_IOCTL_PM_GET_CPU_STATE	\
+	_IOWR(ACRN_IOCTL_TYPE, 0x60, __u64)
+
 #endif /* _UAPI_ACRN_H */