# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 294b3a447dce176db3ca11afed1d7317d5ba36db
# Parent 201d48272a57a650a264b9672c14fb6caa86d8e7
Provide a simpler, higher-level interface for mapping in pages from another
domain.
I also added a one-liner that causes xenbus_dev_(error|fatal) to output
to the kernel log buffer (and thus syslog) which was invaluable to me
while debugging (by default, error messages only appear in xenstore).
Signed-off-by: Ryan Wilson <hap9@xxxxxxxxxxxxxx>
diff -r 201d48272a57 -r 294b3a447dce
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_client.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_client.c Thu Feb 16
22:00:00 2006
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_client.c Thu Feb 16
22:37:40 2006
@@ -30,6 +30,7 @@
#include <xen/evtchn.h>
#include <xen/gnttab.h>
#include <xen/xenbus.h>
+#include <xen/driver_util.h>
/* xenbus_probe.c */
extern char *kasprintf(const char *fmt, ...);
@@ -139,6 +140,8 @@
BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
dev->has_error = 1;
+ dev_err(&dev->dev, "%s\n", printf_buffer);
+
path_buffer = error_path(dev);
if (path_buffer == NULL) {
@@ -202,7 +205,8 @@
evtchn_op_t op = {
.cmd = EVTCHNOP_alloc_unbound,
.u.alloc_unbound.dom = DOMID_SELF,
- .u.alloc_unbound.remote_dom = dev->otherend_id };
+ .u.alloc_unbound.remote_dom = dev->otherend_id
+ };
int err = HYPERVISOR_event_channel_op(&op);
if (err)
@@ -212,6 +216,167 @@
return err;
}
EXPORT_SYMBOL(xenbus_alloc_evtchn);
+
+
+int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
+{
+ evtchn_op_t op = {
+ .cmd = EVTCHNOP_bind_interdomain,
+ .u.bind_interdomain.remote_dom = dev->otherend_id,
+ .u.bind_interdomain.remote_port = remote_port,
+ };
+
+ int err = HYPERVISOR_event_channel_op(&op);
+ if (err)
+ xenbus_dev_fatal(dev, err,
+ "binding to event channel %d from domain %d",
+ remote_port, dev->otherend_id);
+ else
+ *port = op.u.bind_interdomain.local_port;
+ return err;
+}
+EXPORT_SYMBOL(xenbus_bind_evtchn);
+
+
+int xenbus_free_evtchn(struct xenbus_device *dev, int port)
+{
+ evtchn_op_t op = {
+ .cmd = EVTCHNOP_close,
+ .u.close.port = port,
+ };
+ int err = HYPERVISOR_event_channel_op(&op);
+ if (err)
+ xenbus_dev_error(dev, err, "freeing event channel %d", port);
+ return err;
+}
+
+
+/* Based on Rusty Russell's skeleton driver's map_page */
+int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void
**vaddr)
+{
+ struct gnttab_map_grant_ref op = {
+ .flags = GNTMAP_host_map,
+ .ref = gnt_ref,
+ .dom = dev->otherend_id,
+ };
+ struct vm_struct *area;
+
+ *vaddr = NULL;
+
+ area = alloc_vm_area(PAGE_SIZE);
+ if (!area)
+ return -ENOMEM;
+
+ op.host_addr = (unsigned long)area->addr;
+
+ lock_vm_area(area);
+ BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ unlock_vm_area(area);
+
+ if (op.status != GNTST_okay) {
+ free_vm_area(area);
+ xenbus_dev_fatal(dev, op.status,
+ "mapping in shared page %d from domain %d",
+ gnt_ref, dev->otherend_id);
+ return op.status;
+ }
+
+ /* Stuff the handle in an unused field */
+ area->phys_addr = (unsigned long)op.handle;
+
+ *vaddr = area->addr;
+ return 0;
+}
+EXPORT_SYMBOL(xenbus_map_ring_valloc);
+
+
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
+ grant_handle_t *handle, void *vaddr)
+{
+ struct gnttab_map_grant_ref op = {
+ .host_addr = (unsigned long)vaddr,
+ .flags = GNTMAP_host_map,
+ .ref = gnt_ref,
+ .dom = dev->otherend_id,
+ };
+
+ BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+
+ if (op.status != GNTST_okay) {
+ xenbus_dev_fatal(dev, op.status,
+ "mapping in shared page %d from domain %d",
+ gnt_ref, dev->otherend_id);
+ } else
+ *handle = op.handle;
+
+ return op.status;
+}
+EXPORT_SYMBOL(xenbus_map_ring);
+
+
+/* Based on Rusty Russell's skeleton driver's unmap_page */
+int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
+{
+ struct vm_struct *area;
+ struct gnttab_unmap_grant_ref op = {
+ .host_addr = (unsigned long)vaddr,
+ };
+
+ /* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr)
+ * method so that we don't have to muck with vmalloc internals here.
+ * We could force the user to hang on to their struct vm_struct from
+ * xenbus_map_ring_valloc, but these 6 lines considerably simplify
+ * this API.
+ */
+ read_lock(&vmlist_lock);
+ for (area = vmlist; area != NULL; area = area->next) {
+ if (area->addr == vaddr)
+ break;
+ }
+ read_unlock(&vmlist_lock);
+
+ if (!area) {
+ xenbus_dev_error(dev, -ENOENT,
+ "can't find mapped virtual address %p", vaddr);
+ return GNTST_bad_virt_addr;
+ }
+
+ op.handle = (grant_handle_t)area->phys_addr;
+
+ lock_vm_area(area);
+ BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ unlock_vm_area(area);
+
+ if (op.status == GNTST_okay)
+ free_vm_area(area);
+ else
+ xenbus_dev_error(dev, op.status,
+ "unmapping page at handle %d error %d",
+ (int16_t)area->phys_addr, op.status);
+
+ return op.status;
+}
+EXPORT_SYMBOL(xenbus_unmap_ring_vfree);
+
+
+int xenbus_unmap_ring(struct xenbus_device *dev,
+ grant_handle_t handle, void *vaddr)
+{
+ struct gnttab_unmap_grant_ref op = {
+ .host_addr = (unsigned long)vaddr,
+ .handle = handle,
+ };
+
+ BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+
+ if (op.status != GNTST_okay)
+ xenbus_dev_error(dev, op.status,
+ "unmapping page at handle %d error %d",
+ handle, op.status);
+
+ return op.status;
+}
+EXPORT_SYMBOL(xenbus_unmap_ring);
XenbusState xenbus_read_driver_state(const char *path)
diff -r 201d48272a57 -r 294b3a447dce linux-2.6-xen-sparse/include/xen/xenbus.h
--- a/linux-2.6-xen-sparse/include/xen/xenbus.h Thu Feb 16 22:00:00 2006
+++ b/linux-2.6-xen-sparse/include/xen/xenbus.h Thu Feb 16 22:37:40 2006
@@ -34,6 +34,7 @@
#include <linux/device.h>
#include <linux/notifier.h>
#include <asm/semaphore.h>
+#include <xen/interface/grant_table.h>
#include <xen/interface/io/xenbus.h>
#include <xen/interface/io/xs_wire.h>
@@ -209,12 +210,54 @@
/**
+ * Map a page of memory into this domain from another domain's grant table.
+ * xenbus_map_ring_valloc allocates a page of virtual address space, maps the
+ * page to that address, and sets *vaddr to that address.
+ * xenbus_map_ring does not allocate the virtual address space (you must do
+ * this yourself!). It only maps in the page to the specified address.
+ * Returns 0 on success, and GNTST_* (see xen/include/public/grant_table.h) or
+ * -ENOMEM on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the error message will be saved in XenStore.
+ */
+int xenbus_map_ring_valloc(struct xenbus_device *dev,
+ int gnt_ref, void **vaddr);
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
+ grant_handle_t *handle, void *vaddr);
+
+
+/**
+ * Unmap a page of memory in this domain that was imported from another domain.
+ * Use xenbus_unmap_ring_vfree if you mapped in your memory with
+ * xenbus_map_ring_valloc (it will free the virtual address space).
+ * Returns 0 on success and returns GNTST_* on error
+ * (see xen/include/public/grant_table.h).
+ */
+int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
+int xenbus_unmap_ring(struct xenbus_device *dev,
+ grant_handle_t handle, void *vaddr);
+
+
+/**
* Allocate an event channel for the given xenbus_device, assigning the newly
* created local port to *port. Return 0 on success, or -errno on error. On
* error, the device will switch to XenbusStateClosing, and the error will be
* saved in the store.
*/
int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
+
+
+/**
+ * Bind to an existing interdomain event channel in another domain. Returns 0
+ * on success and stores the local port in *port. On error, returns -errno,
+ * switches the device to XenbusStateClosing, and saves the error in XenStore.
+ */
+int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);
+
+
+/**
+ * Free an existing event channel. Returns 0 on success or -errno on error.
+ */
+int xenbus_free_evtchn(struct xenbus_device *dev, int port);
/**
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