diff options
Diffstat (limited to 'hw/i386/kvm/xen_gnttab.c')
| -rw-r--r-- | hw/i386/kvm/xen_gnttab.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/hw/i386/kvm/xen_gnttab.c b/hw/i386/kvm/xen_gnttab.c new file mode 100644 index 0000000000..1e691ded32 --- /dev/null +++ b/hw/i386/kvm/xen_gnttab.c @@ -0,0 +1,232 @@ +/* + * 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; +} |