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authorDaniel De Graaf <dgdegra@tycho.nsa.gov>2011-12-19 14:55:14 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-12-20 17:02:35 -0500
commit2c5d37d30fbd27d424a18abc16786cb152a37017 (patch)
treea721776de9157570120057a31de7e271cbe56b28 /drivers/xen/xenbus
parentcb85f123cd2393581bcffad335bfc6bcdd58569c (diff)
downloadvexpress-lsk-2c5d37d30fbd27d424a18abc16786cb152a37017.tar.gz
xenbus: Support HVM backends
Add HVM implementations of xenbus_(map,unmap)_ring_v(alloc,free) so that ring mappings can be done without using GNTMAP_contains_pte which is not supported on HVM. This also removes the need to use vmlist_lock on PV by tracking the allocated xenbus rings. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> [v1: Fix compile error when XENBUS_FRONTEND is defined as module] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen/xenbus')
-rw-r--r--drivers/xen/xenbus/xenbus_client.c176
-rw-r--r--drivers/xen/xenbus/xenbus_probe.c2
-rw-r--r--drivers/xen/xenbus/xenbus_probe.h2
3 files changed, 159 insertions, 21 deletions
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 1906125eab4..0fa52916ad0 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -32,15 +32,39 @@
#include <linux/slab.h>
#include <linux/types.h>
+#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/export.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/page.h>
#include <xen/interface/xen.h>
#include <xen/interface/event_channel.h>
+#include <xen/balloon.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/xenbus.h>
+#include <xen/xen.h>
+
+#include "xenbus_probe.h"
+
+struct xenbus_map_node {
+ struct list_head next;
+ union {
+ struct vm_struct *area; /* PV */
+ struct page *page; /* HVM */
+ };
+ grant_handle_t handle;
+};
+
+static DEFINE_SPINLOCK(xenbus_valloc_lock);
+static LIST_HEAD(xenbus_valloc_pages);
+
+struct xenbus_ring_ops {
+ int (*map)(struct xenbus_device *dev, int gnt, void **vaddr);
+ int (*unmap)(struct xenbus_device *dev, void *vaddr);
+};
+
+static const struct xenbus_ring_ops *ring_ops __read_mostly;
const char *xenbus_strstate(enum xenbus_state state)
{
@@ -436,19 +460,33 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
*/
int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
{
+ return ring_ops->map(dev, gnt_ref, vaddr);
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
+
+static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
+ int gnt_ref, void **vaddr)
+{
struct gnttab_map_grant_ref op = {
.flags = GNTMAP_host_map | GNTMAP_contains_pte,
.ref = gnt_ref,
.dom = dev->otherend_id,
};
+ struct xenbus_map_node *node;
struct vm_struct *area;
pte_t *pte;
*vaddr = NULL;
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
area = alloc_vm_area(PAGE_SIZE, &pte);
- if (!area)
+ if (!area) {
+ kfree(node);
return -ENOMEM;
+ }
op.host_addr = arbitrary_virt_to_machine(pte).maddr;
@@ -457,19 +495,59 @@ int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
if (op.status != GNTST_okay) {
free_vm_area(area);
+ kfree(node);
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;
+ node->handle = op.handle;
+ node->area = area;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_add(&node->next, &xenbus_valloc_pages);
+ spin_unlock(&xenbus_valloc_lock);
*vaddr = area->addr;
return 0;
}
-EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
+
+static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
+ int gnt_ref, void **vaddr)
+{
+ struct xenbus_map_node *node;
+ int err;
+ void *addr;
+
+ *vaddr = NULL;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
+ if (err)
+ goto out_err;
+
+ addr = pfn_to_kaddr(page_to_pfn(node->page));
+
+ err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
+ if (err)
+ goto out_err;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_add(&node->next, &xenbus_valloc_pages);
+ spin_unlock(&xenbus_valloc_lock);
+
+ *vaddr = addr;
+ return 0;
+
+ out_err:
+ free_xenballooned_pages(1, &node->page);
+ kfree(node);
+ return err;
+}
/**
@@ -525,32 +603,36 @@ EXPORT_SYMBOL_GPL(xenbus_map_ring);
*/
int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
{
- struct vm_struct *area;
+ return ring_ops->unmap(dev, vaddr);
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
+
+static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
+{
+ struct xenbus_map_node *node;
struct gnttab_unmap_grant_ref op = {
.host_addr = (unsigned long)vaddr,
};
unsigned int level;
- /* 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;
+ spin_lock(&xenbus_valloc_lock);
+ list_for_each_entry(node, &xenbus_valloc_pages, next) {
+ if (node->area->addr == vaddr) {
+ list_del(&node->next);
+ goto found;
+ }
}
- read_unlock(&vmlist_lock);
+ node = NULL;
+ found:
+ spin_unlock(&xenbus_valloc_lock);
- if (!area) {
+ if (!node) {
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;
+ op.handle = node->handle;
op.host_addr = arbitrary_virt_to_machine(
lookup_address((unsigned long)vaddr, &level)).maddr;
@@ -558,16 +640,50 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
BUG();
if (op.status == GNTST_okay)
- free_vm_area(area);
+ free_vm_area(node->area);
else
xenbus_dev_error(dev, op.status,
"unmapping page at handle %d error %d",
- (int16_t)area->phys_addr, op.status);
+ node->handle, op.status);
+ kfree(node);
return op.status;
}
-EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
+static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
+{
+ int rv;
+ struct xenbus_map_node *node;
+ void *addr;
+
+ spin_lock(&xenbus_valloc_lock);
+ list_for_each_entry(node, &xenbus_valloc_pages, next) {
+ addr = pfn_to_kaddr(page_to_pfn(node->page));
+ if (addr == vaddr) {
+ list_del(&node->next);
+ goto found;
+ }
+ }
+ node = NULL;
+ found:
+ spin_unlock(&xenbus_valloc_lock);
+
+ if (!node) {
+ xenbus_dev_error(dev, -ENOENT,
+ "can't find mapped virtual address %p", vaddr);
+ return GNTST_bad_virt_addr;
+ }
+
+ rv = xenbus_unmap_ring(dev, node->handle, addr);
+
+ if (!rv)
+ free_xenballooned_pages(1, &node->page);
+ else
+ WARN(1, "Leaking %p\n", vaddr);
+
+ kfree(node);
+ return rv;
+}
/**
* xenbus_unmap_ring
@@ -617,3 +733,21 @@ enum xenbus_state xenbus_read_driver_state(const char *path)
return result;
}
EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
+
+static const struct xenbus_ring_ops ring_ops_pv = {
+ .map = xenbus_map_ring_valloc_pv,
+ .unmap = xenbus_unmap_ring_vfree_pv,
+};
+
+static const struct xenbus_ring_ops ring_ops_hvm = {
+ .map = xenbus_map_ring_valloc_hvm,
+ .unmap = xenbus_unmap_ring_vfree_hvm,
+};
+
+void __init xenbus_ring_ops_init(void)
+{
+ if (xen_pv_domain())
+ ring_ops = &ring_ops_pv;
+ else
+ ring_ops = &ring_ops_hvm;
+}
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 1b178c6e893..1c05b2508ae 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -730,6 +730,8 @@ static int __init xenbus_init(void)
if (!xen_domain())
return -ENODEV;
+ xenbus_ring_ops_init();
+
if (xen_hvm_domain()) {
uint64_t v = 0;
err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
diff --git a/drivers/xen/xenbus/xenbus_probe.h b/drivers/xen/xenbus/xenbus_probe.h
index 9b1de4e34c6..460d784a769 100644
--- a/drivers/xen/xenbus/xenbus_probe.h
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -76,4 +76,6 @@ extern void xenbus_otherend_changed(struct xenbus_watch *watch,
extern int xenbus_read_otherend_details(struct xenbus_device *xendev,
char *id_node, char *path_node);
+void xenbus_ring_ops_init(void);
+
#endif