@@ -179,6 +179,21 @@ xenforeignmemory_resource_handle *xenforeignmemory_map_resource(
int xenforeignmemory_unmap_resource(
xenforeignmemory_handle *fmem, xenforeignmemory_resource_handle *fres);
+/**
+ * Determine the maximum size of a specific resource.
+ *
+ * @parm fmem handle to the open foreignmemory interface
+ * @parm domid the domain id
+ * @parm type the resource type
+ * @parm id the type-specific resource identifier
+ *
+ * Return 0 on success and fills in *nr_frames. Sets errno and return -1 on
+ * error.
+ */
+int xenforeignmemory_resource_size(
+ xenforeignmemory_handle *fmem, domid_t domid, unsigned int type,
+ unsigned int id, unsigned long *nr_frames);
+
#endif
/*
@@ -2,7 +2,7 @@ XEN_ROOT = $(CURDIR)/../../..
include $(XEN_ROOT)/tools/Rules.mk
MAJOR = 1
-MINOR = 3
+MINOR = 4
SRCS-y += core.c
SRCS-$(CONFIG_Linux) += linux.c
@@ -188,6 +188,24 @@ int xenforeignmemory_unmap_resource(
return rc;
}
+int xenforeignmemory_resource_size(
+ xenforeignmemory_handle *fmem, domid_t domid, unsigned int type,
+ unsigned int id, unsigned long *nr_frames)
+{
+ xenforeignmemory_resource_handle fres = {
+ .domid = domid,
+ .type = type,
+ .id = id,
+ };
+ int rc = osdep_xenforeignmemory_map_resource(fmem, &fres);
+
+ if ( rc )
+ return rc;
+
+ *nr_frames = fres.nr_frames;
+ return 0;
+}
+
/*
* Local variables:
* mode: C
@@ -119,6 +119,10 @@ int osdep_xenforeignmemory_map_resource(xenforeignmemory_handle *fmem,
};
int rc;
+ if ( !fres->addr && !fres->nr_frames )
+ /* Request for resource size. Skip mmap(). */
+ goto skip_mmap;
+
fres->addr = mmap(fres->addr, fres->nr_frames << PAGE_SHIFT,
fres->prot, fres->flags | MAP_SHARED, fmem->fd, 0);
if ( fres->addr == MAP_FAILED )
@@ -126,6 +130,7 @@ int osdep_xenforeignmemory_map_resource(xenforeignmemory_handle *fmem,
mr.addr = (uintptr_t)fres->addr;
+ skip_mmap:
rc = ioctl(fmem->fd, IOCTL_PRIVCMD_MMAP_RESOURCE, &mr);
if ( rc )
{
@@ -136,13 +141,20 @@ int osdep_xenforeignmemory_map_resource(xenforeignmemory_handle *fmem,
else
errno = EOPNOTSUPP;
- saved_errno = errno;
- osdep_xenforeignmemory_unmap_resource(fmem, fres);
- errno = saved_errno;
+ if ( fres->addr )
+ {
+ saved_errno = errno;
+ osdep_xenforeignmemory_unmap_resource(fmem, fres);
+ errno = saved_errno;
+ }
return -1;
}
+ /* If requesting size, copy back. */
+ if ( !fres->addr )
+ fres->nr_frames = mr.num;
+
return 0;
}
@@ -19,3 +19,7 @@ VERS_1.3 {
xenforeignmemory_map_resource;
xenforeignmemory_unmap_resource;
} VERS_1.2;
+VERS_1.4 {
+ global:
+ xenforeignmemory_resource_size;
+} VERS_1.3;
@@ -312,6 +312,10 @@ int osdep_xenforeignmemory_map_resource(
};
int rc;
+ if ( !fres->addr && !fres->nr_frames )
+ /* Request for resource size. Skip mmap(). */
+ goto skip_mmap;
+
fres->addr = mmap(fres->addr, fres->nr_frames << PAGE_SHIFT,
fres->prot, fres->flags | MAP_SHARED, fmem->fd, 0);
if ( fres->addr == MAP_FAILED )
@@ -319,6 +323,7 @@ int osdep_xenforeignmemory_map_resource(
mr.addr = (uintptr_t)fres->addr;
+ skip_mmap:
rc = ioctl(fmem->fd, IOCTL_PRIVCMD_MMAP_RESOURCE, &mr);
if ( rc )
{
@@ -329,13 +334,20 @@ int osdep_xenforeignmemory_map_resource(
else
errno = EOPNOTSUPP;
- saved_errno = errno;
- (void)osdep_xenforeignmemory_unmap_resource(fmem, fres);
- errno = saved_errno;
+ if ( fres->addr )
+ {
+ saved_errno = errno;
+ osdep_xenforeignmemory_unmap_resource(fmem, fres);
+ errno = saved_errno;
+ }
return -1;
}
+ /* If requesting size, copy back. */
+ if ( !fres->addr )
+ fres->nr_frames = mr.num;
+
return 0;
}