xen.h

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 */
#define DOMID_IO   (0x7FF1U)

/*
 * DOMID_XEN is used to allow privileged domains to map restricted parts of
 * Xen's heap space (e.g., the machine_to_phys table).
 * This only makes sense in MMUEXT_SET_FOREIGNDOM, and is only permitted if
 * the caller is privileged.
 */
#define DOMID_XEN  (0x7FF2U)

/*
 * Send an array of these to HYPERVISOR_mmu_update().
 * NB. The fields are natural pointer/address size for this architecture.
 */
struct mmu_update {
    uint64_t ptr;       /* Machine address of PTE. */
    uint64_t val;       /* New contents of PTE.    */
};
DEFINE_GUEST_HANDLE_STRUCT(mmu_update);

/*
 * Send an array of these to HYPERVISOR_multicall().
 * NB. The fields are natural register size for this architecture.
 */
struct multicall_entry {
    unsigned long op;
    long result;
    unsigned long args[6];
};
DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);

/*
 * Event channel endpoints per domain:
 *  1024 if a long is 32 bits; 4096 if a long is 64 bits.
 */
#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * 64)

struct vcpu_time_info {
	/*
	 * Updates to the following values are preceded and followed
	 * by an increment of 'version'. The guest can therefore
	 * detect updates by looking for changes to 'version'. If the
	 * least-significant bit of the version number is set then an
	 * update is in progress and the guest must wait to read a
	 * consistent set of values.  The correct way to interact with
	 * the version number is similar to Linux's seqlock: see the
	 * implementations of read_seqbegin/read_seqretry.
	 */
	uint32_t version;
	uint32_t pad0;
	uint64_t tsc_timestamp;   /* TSC at last update of time vals.  */
	uint64_t system_time;     /* Time, in nanosecs, since boot.    */
	/*
	 * Current system time:
	 *   system_time + ((tsc - tsc_timestamp) << tsc_shift) * tsc_to_system_mul
	 * CPU frequency (Hz):
	 *   ((10^9 << 32) / tsc_to_system_mul) >> tsc_shift
	 */
	uint32_t tsc_to_system_mul;
	int8_t   tsc_shift;
	int8_t   pad1[3];
}; /* 32 bytes */

struct vcpu_info {
	/*
	 * 'evtchn_upcall_pending' is written non-zero by Xen to indicate
	 * a pending notification for a particular VCPU. It is then cleared
	 * by the guest OS /before/ checking for pending work, thus avoiding
	 * a set-and-check race. Note that the mask is only accessed by Xen
	 * on the CPU that is currently hosting the VCPU. This means that the
	 * pending and mask flags can be updated by the guest without special
	 * synchronisation (i.e., no need for the x86 LOCK prefix).
	 * This may seem suboptimal because if the pending flag is set by
	 * a different CPU then an IPI may be scheduled even when the mask
	 * is set. However, note:
	 *  1. The task of 'interrupt holdoff' is covered by the per-event-
	 *     channel mask bits. A 'noisy' event that is continually being
	 *     triggered can be masked at source at this very precise
	 *     granularity.
	 *  2. The main purpose of the per-VCPU mask is therefore to restrict
	 *     reentrant execution: whether for concurrency control, or to
	 *     prevent unbounded stack usage. Whatever the purpose, we expect
	 *     that the mask will be asserted only for short periods at a time,
	 *     and so the likelihood of a 'spurious' IPI is suitably small.
	 * The mask is read before making an event upcall to the guest: a
	 * non-zero mask therefore guarantees that the VCPU will not receive
	 * an upcall activation. The mask is cleared when the VCPU requests
	 * to block: this avoids wakeup-waiting races.
	 */
	uint8_t evtchn_upcall_pending;
	uint8_t evtchn_upcall_mask;
	unsigned long evtchn_pending_sel;
	struct arch_vcpu_info arch;
	struct vcpu_time_info time;
}; /* 64 bytes (x86) */

/*
 * Xen/kernel shared data -- pointer provided in start_info.
 * NB. We expect that this struct is smaller than a page.
 */
struct shared_info {
	struct vcpu_info vcpu_info[MAX_VIRT_CPUS];

	/*
	 * A domain can create "event channels" on which it can send and receive
	 * asynchronous event notifications. There are three classes of event that
	 * are delivered by this mechanism:
	 *  1. Bi-directional inter- and intra-domain connections. Domains must
	 *     arrange out-of-band to set up a connection (usually by allocating
	 *     an unbound 'listener' port and avertising that via a storage service
	 *     such as xenstore).
	 *  2. Physical interrupts. A domain with suitable hardware-access
	 *     privileges can bind an event-channel port to a physical interrupt
	 *     source.
	 *  3. Virtual interrupts ('events'). A domain can bind an event-channel
	 *     port to a virtual interrupt source, such as the virtual-timer
	 *     device or the emergency console.
	 *
	 * Event channels are addressed by a "port index". Each channel is
	 * associated with two bits of information:
	 *  1. PENDING -- notifies the domain that there is a pending notification
	 *     to be processed. This bit is cleared by the guest.
	 *  2. MASK -- if this bit is clear then a 0->1 transition of PENDING
	 *     will cause an asynchronous upcall to be scheduled. This bit is only
	 *     updated by the guest. It is read-only within Xen. If a channel
	 *     becomes pending while the channel is masked then the 'edge' is lost
	 *     (i.e., when the channel is unmasked, the guest must manually handle
	 *     pending notifications as no upcall will be scheduled by Xen).
	 *
	 * To expedite scanning of pending notifications, any 0->1 pending
	 * transition on an unmasked channel causes a corresponding bit in a
	 * per-vcpu selector word to be set. Each bit in the selector covers a
	 * 'C long' in the PENDING bitfield array.
	 */
	unsigned long evtchn_pending[sizeof(unsigned long) * 8];
	unsigned long evtchn_mask[sizeof(unsigned long) * 8];

	/*
	 * Wallclock time: updated only by control software. Guests should base
	 * their gettimeofday() syscall on this wallclock-base value.
	 */
	uint32_t wc_version;      /* Version counter: see vcpu_time_info_t. */
	uint32_t wc_sec;          /* Secs  00:00:00 UTC, Jan 1, 1970.  */
	uint32_t wc_nsec;         /* Nsecs 00:00:00 UTC, Jan 1, 1970.  */

	struct arch_shared_info arch;

};

/*
 * Start-of-day memory layout for the initial domain (DOM0):
 *  1. The domain is started within contiguous virtual-memory region.
 *  2. The contiguous region begins and ends on an aligned 4MB boundary.
 *  3. The region start corresponds to the load address of the OS image.
 *     If the load address is not 4MB aligned then the address is rounded down.
 *  4. This the order of bootstrap elements in the initial virtual region:
 *      a. relocated kernel image
 *      b. initial ram disk              [mod_start, mod_len]
 *      c. list of allocated page frames [mfn_list, nr_pages]
 *      d. start_info_t structure        [register ESI (x86)]
 *      e. bootstrap page tables         [pt_base, CR3 (x86)]
 *      f. bootstrap stack               [register ESP (x86)]
 *  5. Bootstrap elements are packed together, but each is 4kB-aligned.
 *  6. The initial ram disk may be omitted.
 *  7. The list of page frames forms a contiguous 'pseudo-physical' memory
 *     layout for the domain. In particular, the bootstrap virtual-memory
 *     region is a 1:1 mapping to the first section of the pseudo-physical map.
 *  8. All bootstrap elements are mapped read-writable for the guest OS. The
 *     only exception is the bootstrap page table, which is mapped read-only.
 *  9. There is guaranteed to be at least 512kB padding after the final
 *     bootstrap element. If necessary, the bootstrap virtual region is
 *     extended by an extra 4MB to ensure this.
 */

#define MAX_GUEST_CMDLINE 1024
struct start_info {
	/* THE FOLLOWING ARE FILLED IN BOTH ON INITIAL BOOT AND ON RESUME.    */
	char magic[32];             /* "xen-<version>-<platform>".            */
	unsigned long nr_pages;     /* Total pages allocated to this domain.  */
	unsigned long shared_info;  /* MACHINE address of shared info struct. */
	uint32_t flags;             /* SIF_xxx flags.                         */
	unsigned long store_mfn;    /* MACHINE page number of shared page.    */
	uint32_t store_evtchn;      /* Event channel for store communication. */
	union {
		struct {
			unsigned long mfn;  /* MACHINE page number of console page.   */
			uint32_t  evtchn;   /* Event channel for console page.        */
		} domU;
		struct {
			uint32_t info_off;  /* Offset of console_info struct.         */
			uint32_t info_size; /* Size of console_info struct from start.*/
		} dom0;
	} console;
	/* THE FOLLOWING ARE ONLY FILLED IN ON INITIAL BOOT (NOT RESUME).     */
	unsigned long pt_base;      /* VIRTUAL address of page directory.     */
	unsigned long nr_pt_frames; /* Number of bootstrap p.t. frames.       */
	unsigned long mfn_list;     /* VIRTUAL address of page-frame list.    */
	unsigned long mod_start;    /* VIRTUAL address of pre-loaded module.  */
	unsigned long mod_len;      /* Size (bytes) of pre-loaded module.     */
	int8_t cmd_line[MAX_GUEST_CMDLINE];
};

/* These flags are passed in the 'flags' field of start_info_t. */
#define SIF_PRIVILEGED    (1<<0)  /* Is the domain privileged? */
#define SIF_INITDOMAIN    (1<<1)  /* Is this the initial control domain? */

typedef uint64_t cpumap_t;

typedef uint8_t xen_domain_handle_t[16];

/* Turn a plain number into a C unsigned long constant. */
#define __mk_unsigned_long(x) x ## UL
#define mk_unsigned_long(x) __mk_unsigned_long(x)

#else /* __ASSEMBLY__ */

/* In assembly code we cannot use C numeric constant suffixes. */
#define mk_unsigned_long(x) x

#endif /* !__ASSEMBLY__ */

#endif /* __XEN_PUBLIC_XEN_H__ */