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/*
* QEMU Xen emulation: Grant table support
*
* Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Authors: David Woodhouse <dwmw2@infradead.org>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "qemu/module.h"
#include "qemu/lockable.h"
#include "qemu/main-loop.h"
#include "qapi/error.h"
#include "qom/object.h"
#include "exec/target_page.h"
#include "exec/address-spaces.h"
#include "migration/vmstate.h"
#include "hw/sysbus.h"
#include "hw/xen/xen.h"
#include "xen_overlay.h"
#include "xen_gnttab.h"
#include "sysemu/kvm.h"
#include "sysemu/kvm_xen.h"
#include "hw/xen/interface/memory.h"
#include "hw/xen/interface/grant_table.h"
#define TYPE_XEN_GNTTAB "xen-gnttab"
OBJECT_DECLARE_SIMPLE_TYPE(XenGnttabState, XEN_GNTTAB)
#define XEN_PAGE_SHIFT 12
#define XEN_PAGE_SIZE (1ULL << XEN_PAGE_SHIFT)
#define ENTRIES_PER_FRAME_V1 (XEN_PAGE_SIZE / sizeof(grant_entry_v1_t))
struct XenGnttabState {
/*< private >*/
SysBusDevice busdev;
/*< public >*/
QemuMutex gnt_lock;
uint32_t nr_frames;
uint32_t max_frames;
union {
grant_entry_v1_t *v1;
/* Theoretically, v2 support could be added here. */
} entries;
MemoryRegion gnt_frames;
MemoryRegion *gnt_aliases;
uint64_t *gnt_frame_gpas;
};
struct XenGnttabState *xen_gnttab_singleton;
static void xen_gnttab_realize(DeviceState *dev, Error **errp)
{
XenGnttabState *s = XEN_GNTTAB(dev);
int i;
if (xen_mode != XEN_EMULATE) {
error_setg(errp, "Xen grant table support is for Xen emulation");
return;
}
s->nr_frames = 0;
s->max_frames = kvm_xen_get_gnttab_max_frames();
memory_region_init_ram(&s->gnt_frames, OBJECT(dev), "xen:grant_table",
XEN_PAGE_SIZE * s->max_frames, &error_abort);
memory_region_set_enabled(&s->gnt_frames, true);
s->entries.v1 = memory_region_get_ram_ptr(&s->gnt_frames);
memset(s->entries.v1, 0, XEN_PAGE_SIZE * s->max_frames);
/* Create individual page-sizes aliases for overlays */
s->gnt_aliases = (void *)g_new0(MemoryRegion, s->max_frames);
s->gnt_frame_gpas = (void *)g_new(uint64_t, s->max_frames);
for (i = 0; i < s->max_frames; i++) {
memory_region_init_alias(&s->gnt_aliases[i], OBJECT(dev),
NULL, &s->gnt_frames,
i * XEN_PAGE_SIZE, XEN_PAGE_SIZE);
s->gnt_frame_gpas[i] = INVALID_GPA;
}
qemu_mutex_init(&s->gnt_lock);
xen_gnttab_singleton = s;
}
static int xen_gnttab_post_load(void *opaque, int version_id)
{
XenGnttabState *s = XEN_GNTTAB(opaque);
uint32_t i;
for (i = 0; i < s->nr_frames; i++) {
if (s->gnt_frame_gpas[i] != INVALID_GPA) {
xen_overlay_do_map_page(&s->gnt_aliases[i], s->gnt_frame_gpas[i]);
}
}
return 0;
}
static bool xen_gnttab_is_needed(void *opaque)
{
return xen_mode == XEN_EMULATE;
}
static const VMStateDescription xen_gnttab_vmstate = {
.name = "xen_gnttab",
.version_id = 1,
.minimum_version_id = 1,
.needed = xen_gnttab_is_needed,
.post_load = xen_gnttab_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT32(nr_frames, XenGnttabState),
VMSTATE_VARRAY_UINT32(gnt_frame_gpas, XenGnttabState, nr_frames, 0,
vmstate_info_uint64, uint64_t),
VMSTATE_END_OF_LIST()
}
};
static void xen_gnttab_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = xen_gnttab_realize;
dc->vmsd = &xen_gnttab_vmstate;
}
static const TypeInfo xen_gnttab_info = {
.name = TYPE_XEN_GNTTAB,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(XenGnttabState),
.class_init = xen_gnttab_class_init,
};
void xen_gnttab_create(void)
{
xen_gnttab_singleton = XEN_GNTTAB(sysbus_create_simple(TYPE_XEN_GNTTAB,
-1, NULL));
}
static void xen_gnttab_register_types(void)
{
type_register_static(&xen_gnttab_info);
}
type_init(xen_gnttab_register_types)
int xen_gnttab_map_page(uint64_t idx, uint64_t gfn)
{
XenGnttabState *s = xen_gnttab_singleton;
uint64_t gpa = gfn << XEN_PAGE_SHIFT;
if (!s) {
return -ENOTSUP;
}
if (idx >= s->max_frames) {
return -EINVAL;
}
QEMU_IOTHREAD_LOCK_GUARD();
QEMU_LOCK_GUARD(&s->gnt_lock);
xen_overlay_do_map_page(&s->gnt_aliases[idx], gpa);
s->gnt_frame_gpas[idx] = gpa;
if (s->nr_frames <= idx) {
s->nr_frames = idx + 1;
}
return 0;
}
int xen_gnttab_set_version_op(struct gnttab_set_version *set)
{
int ret;
switch (set->version) {
case 1:
ret = 0;
break;
case 2:
/* Behave as before set_version was introduced. */
ret = -ENOSYS;
break;
default:
ret = -EINVAL;
}
set->version = 1;
return ret;
}
int xen_gnttab_get_version_op(struct gnttab_get_version *get)
{
if (get->dom != DOMID_SELF && get->dom != xen_domid) {
return -ESRCH;
}
get->version = 1;
return 0;
}
int xen_gnttab_query_size_op(struct gnttab_query_size *size)
{
XenGnttabState *s = xen_gnttab_singleton;
if (!s) {
return -ENOTSUP;
}
if (size->dom != DOMID_SELF && size->dom != xen_domid) {
size->status = GNTST_bad_domain;
return 0;
}
size->status = GNTST_okay;
size->nr_frames = s->nr_frames;
size->max_nr_frames = s->max_frames;
return 0;
}
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