hw/xen: Support mapping grant frames
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
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@ -37,13 +37,26 @@ OBJECT_DECLARE_SIMPLE_TYPE(XenGnttabState, XEN_GNTTAB)
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#define XEN_PAGE_SHIFT 12
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#define XEN_PAGE_SIZE (1ULL << XEN_PAGE_SHIFT)
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#define ENTRIES_PER_FRAME_V1 (XEN_PAGE_SIZE / sizeof(grant_entry_v1_t))
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struct XenGnttabState {
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/*< private >*/
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SysBusDevice busdev;
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/*< public >*/
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QemuMutex gnt_lock;
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uint32_t nr_frames;
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uint32_t max_frames;
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union {
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grant_entry_v1_t *v1;
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/* Theoretically, v2 support could be added here. */
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} entries;
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MemoryRegion gnt_frames;
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MemoryRegion *gnt_aliases;
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uint64_t *gnt_frame_gpas;
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};
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struct XenGnttabState *xen_gnttab_singleton;
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@ -51,6 +64,7 @@ struct XenGnttabState *xen_gnttab_singleton;
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static void xen_gnttab_realize(DeviceState *dev, Error **errp)
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{
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XenGnttabState *s = XEN_GNTTAB(dev);
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int i;
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if (xen_mode != XEN_EMULATE) {
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error_setg(errp, "Xen grant table support is for Xen emulation");
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@ -58,6 +72,38 @@ static void xen_gnttab_realize(DeviceState *dev, Error **errp)
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}
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s->nr_frames = 0;
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s->max_frames = kvm_xen_get_gnttab_max_frames();
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memory_region_init_ram(&s->gnt_frames, OBJECT(dev), "xen:grant_table",
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XEN_PAGE_SIZE * s->max_frames, &error_abort);
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memory_region_set_enabled(&s->gnt_frames, true);
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s->entries.v1 = memory_region_get_ram_ptr(&s->gnt_frames);
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memset(s->entries.v1, 0, XEN_PAGE_SIZE * s->max_frames);
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/* Create individual page-sizes aliases for overlays */
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s->gnt_aliases = (void *)g_new0(MemoryRegion, s->max_frames);
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s->gnt_frame_gpas = (void *)g_new(uint64_t, s->max_frames);
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for (i = 0; i < s->max_frames; i++) {
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memory_region_init_alias(&s->gnt_aliases[i], OBJECT(dev),
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NULL, &s->gnt_frames,
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i * XEN_PAGE_SIZE, XEN_PAGE_SIZE);
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s->gnt_frame_gpas[i] = INVALID_GPA;
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}
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qemu_mutex_init(&s->gnt_lock);
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xen_gnttab_singleton = s;
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}
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static int xen_gnttab_post_load(void *opaque, int version_id)
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{
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XenGnttabState *s = XEN_GNTTAB(opaque);
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uint32_t i;
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for (i = 0; i < s->nr_frames; i++) {
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if (s->gnt_frame_gpas[i] != INVALID_GPA) {
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xen_overlay_do_map_page(&s->gnt_aliases[i], s->gnt_frame_gpas[i]);
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}
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}
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return 0;
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}
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static bool xen_gnttab_is_needed(void *opaque)
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@ -70,8 +116,11 @@ static const VMStateDescription xen_gnttab_vmstate = {
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.version_id = 1,
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.minimum_version_id = 1,
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.needed = xen_gnttab_is_needed,
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.post_load = xen_gnttab_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32(nr_frames, XenGnttabState),
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VMSTATE_VARRAY_UINT32(gnt_frame_gpas, XenGnttabState, nr_frames, 0,
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vmstate_info_uint64, uint64_t),
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VMSTATE_END_OF_LIST()
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}
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};
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@ -106,6 +155,28 @@ type_init(xen_gnttab_register_types)
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int xen_gnttab_map_page(uint64_t idx, uint64_t gfn)
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{
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return -ENOSYS;
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XenGnttabState *s = xen_gnttab_singleton;
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uint64_t gpa = gfn << XEN_PAGE_SHIFT;
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if (!s) {
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return -ENOTSUP;
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}
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if (idx >= s->max_frames) {
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return -EINVAL;
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}
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QEMU_IOTHREAD_LOCK_GUARD();
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QEMU_LOCK_GUARD(&s->gnt_lock);
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xen_overlay_do_map_page(&s->gnt_aliases[idx], gpa);
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s->gnt_frame_gpas[idx] = gpa;
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if (s->nr_frames <= idx) {
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s->nr_frames = idx + 1;
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}
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return 0;
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}
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@ -49,7 +49,7 @@ struct XenOverlayState {
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struct XenOverlayState *xen_overlay_singleton;
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static void xen_overlay_do_map_page(MemoryRegion *page, uint64_t gpa)
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void xen_overlay_do_map_page(MemoryRegion *page, uint64_t gpa)
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{
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/*
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* Xen allows guests to map the same page as many times as it likes
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@ -21,4 +21,6 @@ int xen_sync_long_mode(void);
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int xen_set_long_mode(bool long_mode);
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bool xen_is_long_mode(void);
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void xen_overlay_do_map_page(MemoryRegion *page, uint64_t gpa);
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#endif /* QEMU_XEN_OVERLAY_H */
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