xref: /linux-6.15/include/xen/interface/vcpu.h (revision 9e2b3e83)

/* SPDX-License-Identifier: MIT */
/******************************************************************************
 * vcpu.h
 *
 * VCPU initialisation, query, and hotplug.
 *
 * Copyright (c) 2005, Keir Fraser <[email protected]>
 */

#ifndef __XEN_PUBLIC_VCPU_H__
#define __XEN_PUBLIC_VCPU_H__

/*
 * Prototype for this hypercall is:
 *	int vcpu_op(int cmd, int vcpuid, void *extra_args)
 * @cmd		   == VCPUOP_??? (VCPU operation).
 * @vcpuid	   == VCPU to operate on.
 * @extra_args == Operation-specific extra arguments (NULL if none).
 */

/*
 * Initialise a VCPU. Each VCPU can be initialised only once. A
 * newly-initialised VCPU will not run until it is brought up by VCPUOP_up.
 *
 * @extra_arg == pointer to vcpu_guest_context structure containing initial
 *				 state for the VCPU.
 */
#define VCPUOP_initialise			 0

/*
 * Bring up a VCPU. This makes the VCPU runnable. This operation will fail
 * if the VCPU has not been initialised (VCPUOP_initialise).
 */
#define VCPUOP_up					 1

/*
 * Bring down a VCPU (i.e., make it non-runnable).
 * There are a few caveats that callers should observe:
 *	1. This operation may return, and VCPU_is_up may return false, before the
 *	   VCPU stops running (i.e., the command is asynchronous). It is a good
 *	   idea to ensure that the VCPU has entered a non-critical loop before
 *	   bringing it down. Alternatively, this operation is guaranteed
 *	   synchronous if invoked by the VCPU itself.
 *	2. After a VCPU is initialised, there is currently no way to drop all its
 *	   references to domain memory. Even a VCPU that is down still holds
 *	   memory references via its pagetable base pointer and GDT. It is good
 *	   practise to move a VCPU onto an 'idle' or default page table, LDT and
 *	   GDT before bringing it down.
 */
#define VCPUOP_down					 2

/* Returns 1 if the given VCPU is up. */
#define VCPUOP_is_up				 3

/*
 * Return information about the state and running time of a VCPU.
 * @extra_arg == pointer to vcpu_runstate_info structure.
 */
#define VCPUOP_get_runstate_info	 4
struct vcpu_runstate_info {
	/* VCPU's current state (RUNSTATE_*). */
	int		 state;
	/* When was current state entered (system time, ns)? */
	uint64_t state_entry_time;
	/*
	 * Update indicator set in state_entry_time:
	 * When activated via VMASST_TYPE_runstate_update_flag, set during
	 * updates in guest memory mapped copy of vcpu_runstate_info.
	 */
#define XEN_RUNSTATE_UPDATE	(1ULL << 63)
	/*
	 * Time spent in each RUNSTATE_* (ns). The sum of these times is
	 * guaranteed not to drift from system time.
	 */
	uint64_t time[4];
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_runstate_info);

/* VCPU is currently running on a physical CPU. */
#define RUNSTATE_running  0

/* VCPU is runnable, but not currently scheduled on any physical CPU. */
#define RUNSTATE_runnable 1

/* VCPU is blocked (a.k.a. idle). It is therefore not runnable. */
#define RUNSTATE_blocked  2

/*
 * VCPU is not runnable, but it is not blocked.
 * This is a 'catch all' state for things like hotplug and pauses by the
 * system administrator (or for critical sections in the hypervisor).
 * RUNSTATE_blocked dominates this state (it is the preferred state).
 */
#define RUNSTATE_offline  3

/*
 * Register a shared memory area from which the guest may obtain its own
 * runstate information without needing to execute a hypercall.
 * Notes:
 *	1. The registered address may be virtual or physical, depending on the
 *	   platform. The virtual address should be registered on x86 systems.
 *	2. Only one shared area may be registered per VCPU. The shared area is
 *	   updated by the hypervisor each time the VCPU is scheduled. Thus
 *	   runstate.state will always be RUNSTATE_running and
 *	   runstate.state_entry_time will indicate the system time at which the
 *	   VCPU was last scheduled to run.
 * @extra_arg == pointer to vcpu_register_runstate_memory_area structure.
 */
#define VCPUOP_register_runstate_memory_area 5
struct vcpu_register_runstate_memory_area {
		union {
				GUEST_HANDLE(vcpu_runstate_info) h;
				struct vcpu_runstate_info *v;
				uint64_t p;
		} addr;
};

/*
 * Set or stop a VCPU's periodic timer. Every VCPU has one periodic timer
 * which can be set via these commands. Periods smaller than one millisecond
 * may not be supported.
 */
#define VCPUOP_set_periodic_timer	 6 /* arg == vcpu_set_periodic_timer_t */
#define VCPUOP_stop_periodic_timer	 7 /* arg == NULL */
struct vcpu_set_periodic_timer {
		uint64_t period_ns;
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_set_periodic_timer);

/*
 * Set or stop a VCPU's single-shot timer. Every VCPU has one single-shot
 * timer which can be set via these commands.
 */
#define VCPUOP_set_singleshot_timer	 8 /* arg == vcpu_set_singleshot_timer_t */
#define VCPUOP_stop_singleshot_timer 9 /* arg == NULL */
struct vcpu_set_singleshot_timer {
		uint64_t timeout_abs_ns;
		uint32_t flags;			   /* VCPU_SSHOTTMR_??? */
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_set_singleshot_timer);

/* Flags to VCPUOP_set_singleshot_timer. */
 /* Require the timeout to be in the future (return -ETIME if it's passed). */
#define _VCPU_SSHOTTMR_future (0)
#define VCPU_SSHOTTMR_future  (1U << _VCPU_SSHOTTMR_future)

/*
 * Register a memory location in the guest address space for the
 * vcpu_info structure.  This allows the guest to place the vcpu_info
 * structure in a convenient place, such as in a per-cpu data area.
 * The pointer need not be page aligned, but the structure must not
 * cross a page boundary.
 */
#define VCPUOP_register_vcpu_info   10  /* arg == struct vcpu_info */
struct vcpu_register_vcpu_info {
    uint64_t mfn;    /* mfn of page to place vcpu_info */
    uint32_t offset; /* offset within page */
    uint32_t rsvd;   /* unused */
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_register_vcpu_info);

/* Send an NMI to the specified VCPU. @extra_arg == NULL. */
#define VCPUOP_send_nmi             11

/*
 * Get the physical ID information for a pinned vcpu's underlying physical
 * processor.  The physical ID informmation is architecture-specific.
 * On x86: id[31:0]=apic_id, id[63:32]=acpi_id.
 * This command returns -EINVAL if it is not a valid operation for this VCPU.
 */
#define VCPUOP_get_physid           12 /* arg == vcpu_get_physid_t */
struct vcpu_get_physid {
	uint64_t phys_id;
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_get_physid);
#define xen_vcpu_physid_to_x86_apicid(physid) ((uint32_t)(physid))
#define xen_vcpu_physid_to_x86_acpiid(physid) ((uint32_t)((physid) >> 32))

/*
 * Register a memory location to get a secondary copy of the vcpu time
 * parameters.  The master copy still exists as part of the vcpu shared
 * memory area, and this secondary copy is updated whenever the master copy
 * is updated (and using the same versioning scheme for synchronisation).
 *
 * The intent is that this copy may be mapped (RO) into userspace so
 * that usermode can compute system time using the time info and the
 * tsc.  Usermode will see an array of vcpu_time_info structures, one
 * for each vcpu, and choose the right one by an existing mechanism
 * which allows it to get the current vcpu number (such as via a
 * segment limit).  It can then apply the normal algorithm to compute
 * system time from the tsc.
 *
 * @extra_arg == pointer to vcpu_register_time_info_memory_area structure.
 */
#define VCPUOP_register_vcpu_time_memory_area   13
DEFINE_GUEST_HANDLE_STRUCT(vcpu_time_info);
struct vcpu_register_time_memory_area {
	union {
		GUEST_HANDLE(vcpu_time_info) h;
		struct pvclock_vcpu_time_info *v;
		uint64_t p;
	} addr;
};
DEFINE_GUEST_HANDLE_STRUCT(vcpu_register_time_memory_area);

#endif /* __XEN_PUBLIC_VCPU_H__ */