This patch adds grant table helper functions to the xen_backend code to
localize error reporting and use of xen_domid.
The patch also defers the call to xengnttab_open() until just before the
initialise method in XenDevOps is invoked. This method is responsible for
mapping the shared ring. No prior method requires access to the grant table.
Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Anthony Perard <anthony.per...@citrix.com>
v2:
- New in v2
---
hw/xen/xen_backend.c | 123 ++++++++++++++++++++++++++++++++++++++-----
include/hw/xen/xen_backend.h | 33 ++++++++++++
2 files changed, 144 insertions(+), 12 deletions(-)
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index 7445b50..50412d6 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -106,6 +106,103 @@ int xen_be_set_state(struct XenDevice *xendev, enum
xenbus_state state)
return 0;
}
+void xen_be_set_max_grant_refs(struct XenDevice *xendev,
+ unsigned int nr_refs)
+{
+ assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV);
+
+ if (xengnttab_set_max_grants(xendev->gnttabdev, nr_refs)) {
+ xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
+ strerror(errno));
+ }
+}
+
+void *xen_be_map_grant_refs(struct XenDevice *xendev, uint32_t *refs,
+ unsigned int nr_refs, int prot)
+{
+ void *ptr;
+
+ assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV);
+
+ ptr = xengnttab_map_domain_grant_refs(xendev->gnttabdev, nr_refs,
+ xen_domid, refs, prot);
+ if (!ptr) {
+ xen_pv_printf(xendev, 0,
+ "xengnttab_map_domain_grant_refs failed: %s\n",
+ strerror(errno));
+ }
+
+ return ptr;
+}
+
+void xen_be_unmap_grant_refs(struct XenDevice *xendev, void *ptr,
+ unsigned int nr_refs)
+{
+ assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV);
+
+ if (xengnttab_unmap(xendev->gnttabdev, ptr, nr_refs)) {
+ xen_pv_printf(xendev, 0, "xengnttab_unmap failed: %s\n",
+ strerror(errno));
+ }
+}
+
+int xen_be_copy_grant_refs(struct XenDevice *xendev,
+ bool to_domain,
+ XenGrantCopySegment segs[],
+ unsigned int nr_segs)
+{
+ xengnttab_grant_copy_segment_t *xengnttab_segs;
+ unsigned int i;
+ int rc;
+
+ assert(xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV);
+
+ xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs);
+
+ for (i = 0; i < nr_segs; i++) {
+ XenGrantCopySegment *seg = &segs[i];
+ xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i];
+
+ if (to_domain) {
+ xengnttab_seg->flags = GNTCOPY_dest_gref;
+ xengnttab_seg->dest.foreign.domid = xen_domid;
+ xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref;
+ xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset;
+ xengnttab_seg->source.virt = seg->source.virt;
+ } else {
+ xengnttab_seg->flags = GNTCOPY_source_gref;
+ xengnttab_seg->source.foreign.domid = xen_domid;
+ xengnttab_seg->source.foreign.ref = seg->source.foreign.ref;
+ xengnttab_seg->source.foreign.offset =
+ seg->source.foreign.offset;
+ xengnttab_seg->dest.virt = seg->dest.virt;
+ }
+
+ xengnttab_seg->len = seg->len;
+ }
+
+ rc = xengnttab_grant_copy(xendev->gnttabdev, nr_segs, xengnttab_segs);
+
+ if (rc) {
+ xen_pv_printf(xendev, 0, "xengnttab_copy failed: %s\n",
+ strerror(errno));
+ }
+
+ for (i = 0; i < nr_segs; i++) {
+ xengnttab_grant_copy_segment_t *xengnttab_seg =
+ &xengnttab_segs[i];
+
+ if (xengnttab_seg->status != GNTST_okay) {
+ xen_pv_printf(xendev, 0, "segment[%u] status: %d\n", i,
+ xengnttab_seg->status);
+ rc = -1;
+ }
+ }
+
+ g_free(xengnttab_segs);
+ return rc;
+}
+
/*
* get xen backend device, allocate a new one if it doesn't exist.
*/
@@ -149,18 +246,6 @@ static struct XenDevice *xen_be_get_xendev(const char
*type, int dom, int dev,
}
qemu_set_cloexec(xenevtchn_fd(xendev->evtchndev));
- if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
- xendev->gnttabdev = xengnttab_open(NULL, 0);
- if (xendev->gnttabdev == NULL) {
- xen_pv_printf(NULL, 0, "can't open gnttab device\n");
- xenevtchn_close(xendev->evtchndev);
- qdev_unplug(DEVICE(xendev), NULL);
- return NULL;
- }
- } else {
- xendev->gnttabdev = NULL;
- }
-
xen_pv_insert_xendev(xendev);
if (xendev->ops->alloc) {
@@ -322,6 +407,16 @@ static int xen_be_try_initialise(struct XenDevice *xendev)
}
}
+ if (xendev->ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
+ xendev->gnttabdev = xengnttab_open(NULL, 0);
+ if (xendev->gnttabdev == NULL) {
+ xen_pv_printf(NULL, 0, "can't open gnttab device\n");
+ return -1;
+ }
+ } else {
+ xendev->gnttabdev = NULL;
+ }
+
if (xendev->ops->initialise) {
rc = xendev->ops->initialise(xendev);
}
@@ -369,6 +464,10 @@ static void xen_be_disconnect(struct XenDevice *xendev,
enum xenbus_state state)
xendev->ops->disconnect) {
xendev->ops->disconnect(xendev);
}
+ if (xendev->gnttabdev) {
+ xengnttab_close(xendev->gnttabdev);
+ xendev->gnttabdev = NULL;
+ }
if (xendev->be_state != state) {
xen_be_set_state(xendev, state);
}
diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
index 3a27692..29bf1c3 100644
--- a/include/hw/xen/xen_backend.h
+++ b/include/hw/xen/xen_backend.h
@@ -42,6 +42,39 @@ void xen_be_register_common(void);
int xen_be_register(const char *type, struct XenDevOps *ops);
int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state);
int xen_be_bind_evtchn(struct XenDevice *xendev);
+void xen_be_set_max_grant_refs(struct XenDevice *xendev,
+ unsigned int nr_refs);
+void *xen_be_map_grant_refs(struct XenDevice *xendev, uint32_t *refs,
+ unsigned int nr_refs, int prot);
+void xen_be_unmap_grant_refs(struct XenDevice *xendev, void *ptr,
+ unsigned int nr_refs);
+
+typedef struct XenGrantCopySegment {
+ union {
+ void *virt;
+ struct {
+ uint32_t ref;
+ off_t offset;
+ } foreign;
+ } source, dest;
+ size_t len;
+} XenGrantCopySegment;
+
+int xen_be_copy_grant_refs(struct XenDevice *xendev,
+ bool to_domain, XenGrantCopySegment segs[],
+ unsigned int nr_segs);
+
+static inline void *xen_be_map_grant_ref(struct XenDevice *xendev,
+ uint32_t ref, int prot)
+{
+ return xen_be_map_grant_refs(xendev, &ref, 1, prot);
+}
+
+static inline void xen_be_unmap_grant_ref(struct XenDevice *xendev,
+ void *ptr)
+{
+ return xen_be_unmap_grant_refs(xendev, ptr, 1);
+}
/* actual backend drivers */
extern struct XenDevOps xen_console_ops; /* xen_console.c */
--
2.1.4
