/******************************************************************************
 * xen.h
 * 
 * Guest OS interface to Xen.
 * 
 * SPDX-License-Identifier: MIT
 *
 * Copyright (c) 2004, K A Fraser
 */

#ifndef __XEN_PUBLIC_XEN_H__
#define __XEN_PUBLIC_XEN_H__

//
// Xen interface version used by Tianocore
//
#define __XEN_INTERFACE_VERSION__ 0x00040400

#include "xen-compat.h"

#if defined(MDE_CPU_IA32) || defined(MDE_CPU_X64)
#include "arch-x86/xen.h"
#elif defined(__arm__) || defined (__aarch64__)
#include "arch-arm/xen.h"
#else
#error "Unsupported architecture"
#endif

#ifndef __ASSEMBLY__
/* Guest handles for primitive C types. */
DEFINE_XEN_GUEST_HANDLE(CHAR8);
__DEFINE_XEN_GUEST_HANDLE(uchar, UINT8);
DEFINE_XEN_GUEST_HANDLE(INT32);
__DEFINE_XEN_GUEST_HANDLE(uint,  UINT32);
#if __XEN_INTERFACE_VERSION__ < 0x00040300
DEFINE_XEN_GUEST_HANDLE(INTN);
__DEFINE_XEN_GUEST_HANDLE(ulong, UINTN);
#endif
DEFINE_XEN_GUEST_HANDLE(VOID);

DEFINE_XEN_GUEST_HANDLE(UINT64);
DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
#endif

/*
 * HYPERCALLS
 */

/* `incontents 100 hcalls List of hypercalls
 * ` enum hypercall_num { // __HYPERVISOR_* => HYPERVISOR_*()
 */

#define __HYPERVISOR_set_trap_table        0
#define __HYPERVISOR_mmu_update            1
#define __HYPERVISOR_set_gdt               2
#define __HYPERVISOR_stack_switch          3
#define __HYPERVISOR_set_callbacks         4
#define __HYPERVISOR_fpu_taskswitch        5
#define __HYPERVISOR_sched_op_compat       6 /* compat since 0x00030101 */
#define __HYPERVISOR_platform_op           7
#define __HYPERVISOR_set_debugreg          8
#define __HYPERVISOR_get_debugreg          9
#define __HYPERVISOR_update_descriptor    10
#define __HYPERVISOR_memory_op            12
#define __HYPERVISOR_multicall            13
#define __HYPERVISOR_update_va_mapping    14
#define __HYPERVISOR_set_timer_op         15
#define __HYPERVISOR_event_channel_op_compat 16 /* compat since 0x00030202 */
#define __HYPERVISOR_xen_version          17
#define __HYPERVISOR_console_io           18
#define __HYPERVISOR_physdev_op_compat    19 /* compat since 0x00030202 */
#define __HYPERVISOR_grant_table_op       20
#define __HYPERVISOR_vm_assist            21
#define __HYPERVISOR_update_va_mapping_otherdomain 22
#define __HYPERVISOR_iret                 23 /* x86 only */
#define __HYPERVISOR_vcpu_op              24
#define __HYPERVISOR_set_segment_base     25 /* x86/64 only */
#define __HYPERVISOR_mmuext_op            26
#define __HYPERVISOR_xsm_op               27
#define __HYPERVISOR_nmi_op               28
#define __HYPERVISOR_sched_op             29
#define __HYPERVISOR_callback_op          30
#define __HYPERVISOR_xenoprof_op          31
#define __HYPERVISOR_event_channel_op     32
#define __HYPERVISOR_physdev_op           33
#define __HYPERVISOR_hvm_op               34
#define __HYPERVISOR_sysctl               35
#define __HYPERVISOR_domctl               36
#define __HYPERVISOR_kexec_op             37
#define __HYPERVISOR_tmem_op              38
#define __HYPERVISOR_xc_reserved_op       39 /* reserved for XenClient */

/* Architecture-specific hypercall definitions. */
#define __HYPERVISOR_arch_0               48
#define __HYPERVISOR_arch_1               49
#define __HYPERVISOR_arch_2               50
#define __HYPERVISOR_arch_3               51
#define __HYPERVISOR_arch_4               52
#define __HYPERVISOR_arch_5               53
#define __HYPERVISOR_arch_6               54
#define __HYPERVISOR_arch_7               55

/* ` } */

/*
 * HYPERCALL COMPATIBILITY.
 */

/* New sched_op hypercall introduced in 0x00030101. */
#if __XEN_INTERFACE_VERSION__ < 0x00030101
#undef __HYPERVISOR_sched_op
#define __HYPERVISOR_sched_op __HYPERVISOR_sched_op_compat
#endif

/* New event-channel and physdev hypercalls introduced in 0x00030202. */
#if __XEN_INTERFACE_VERSION__ < 0x00030202
#undef __HYPERVISOR_event_channel_op
#define __HYPERVISOR_event_channel_op __HYPERVISOR_event_channel_op_compat
#undef __HYPERVISOR_physdev_op
#define __HYPERVISOR_physdev_op __HYPERVISOR_physdev_op_compat
#endif

/* New platform_op hypercall introduced in 0x00030204. */
#if __XEN_INTERFACE_VERSION__ < 0x00030204
#define __HYPERVISOR_dom0_op __HYPERVISOR_platform_op
#endif

#ifndef __ASSEMBLY__

typedef UINT16 domid_t;

/* Domain ids >= DOMID_FIRST_RESERVED cannot be used for ordinary domains. */
#define DOMID_FIRST_RESERVED (0x7FF0U)

/* DOMID_SELF is used in certain contexts to refer to oneself. */
#define DOMID_SELF (0x7FF0U)

/*
 * DOMID_IO is used to restrict page-table updates to mapping I/O memory.
 * Although no Foreign Domain need be specified to map I/O pages, DOMID_IO
 * is useful to ensure that no mappings to the OS's own heap are accidentally
 * installed. (e.g., in Linux this could cause havoc as reference counts
 * aren't adjusted on the I/O-mapping code path).
 * This only makes sense in MMUEXT_SET_FOREIGNDOM, but in that context can
 * be specified by any calling domain.
 */
#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)

/*
 * DOMID_COW is used as the owner of sharable pages */
#define DOMID_COW  (0x7FF3U)

/* DOMID_INVALID is used to identify pages with unknown owner. */
#define DOMID_INVALID (0x7FF4U)

/* Idle domain. */
#define DOMID_IDLE (0x7FFFU)

#if __XEN_INTERFACE_VERSION__ < 0x00040400
/*
 * Event channel endpoints per domain (when using the 2-level ABI):
 *  1024 if a INTN is 32 bits; 4096 if a INTN is 64 bits.
 */
#define NR_EVENT_CHANNELS EVTCHN_2L_NR_CHANNELS
#endif

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 version;
    UINT32 pad0;
    UINT64 tsc_timestamp;   /* TSC at last update of time vals.  */
    UINT64 system_time;     /* Time, in nanosecs, since boot.    */
    /*
     * Current system time:
     *   system_time +
     *   ((((tsc - tsc_timestamp) << tsc_shift) * tsc_to_system_mul) >> 32)
     * CPU frequency (Hz):
     *   ((10^9 << 32) / tsc_to_system_mul) >> tsc_shift
     */
    UINT32 tsc_to_system_mul;
    INT8   tsc_shift;
    INT8   pad1[3];
}; /* 32 bytes */
typedef struct vcpu_time_info vcpu_time_info_t;

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 evtchn_upcall_pending;
#ifdef XEN_HAVE_PV_UPCALL_MASK
    UINT8 evtchn_upcall_mask;
#else /* XEN_HAVE_PV_UPCALL_MASK */
    UINT8 pad0;
#endif /* XEN_HAVE_PV_UPCALL_MASK */
    xen_ulong_t evtchn_pending_sel;
    struct arch_vcpu_info arch;
    struct vcpu_time_info time;
}; /* 64 bytes (x86) */
#ifndef __XEN__
typedef struct vcpu_info vcpu_info_t;
#endif

/*
 * `incontents 200 startofday_shared Start-of-day shared data structure
 * Xen/kernel shared data -- pointer provided in start_info.
 *
 * This structure is defined to be both smaller than a page, and the
 * only data on the shared page, but may vary in actual size even within
 * compatible Xen versions; guests should not rely on the size
 * of this structure remaining constant.
 */
struct shared_info {
    struct vcpu_info vcpu_info[XEN_LEGACY_MAX_VCPUS];

    /*
     * 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 INTN' in the PENDING bitfield array.
     */
    xen_ulong_t evtchn_pending[sizeof(xen_ulong_t) * 8];
    xen_ulong_t evtchn_mask[sizeof(xen_ulong_t) * 8];

    /*
     * Wallclock time: updated only by control software. Guests should base
     * their gettimeofday() syscall on this wallclock-base value.
     */
    UINT32 wc_version;      /* Version counter: see vcpu_time_info_t. */
    UINT32 wc_sec;          /* Secs  00:00:00 UTC, Jan 1, 1970.  */
    UINT32 wc_nsec;         /* Nsecs 00:00:00 UTC, Jan 1, 1970.  */

    struct arch_shared_info arch;

};
#ifndef __XEN__
typedef struct shared_info shared_info_t;
#endif

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

__DEFINE_XEN_GUEST_HANDLE(uint8,  UINT8);
__DEFINE_XEN_GUEST_HANDLE(uint16, UINT16);
__DEFINE_XEN_GUEST_HANDLE(uint32, UINT32);
__DEFINE_XEN_GUEST_HANDLE(uint64, UINT64);

#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__ */

/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */
