[PATCH 1/2] xenbus_client: extend interface to suppurt multi-page ring

From: Bob Liu
Date: Fri Jan 23 2015 - 05:15:20 EST

From: Wei Liu <wei.liu2@xxxxxxxxxx>

Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.

The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.

Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* tpmfront

The interface is documented, as before, in xenbus_client.c.

Change in V2:
* allow ring has arbitrary number of pages <= XENBUS_MAX_RING_PAGES

Change in V3:
* update function prototypes
* carefully deal with types of different sizes

Change in V4:
* use PAGE_KERNEL instead of PAGE_KERNEL_IO to avoid breakage on Arm

Change in V5:
* fix off-by-one error and other minor glitches spotted by Mathew Daley

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
---
drivers/block/xen-blkback/xenbus.c | 5 +-
drivers/block/xen-blkfront.c | 5 +-
drivers/char/tpm/xen-tpmfront.c | 5 +-
drivers/net/xen-netback/netback.c | 4 +-
drivers/net/xen-netfront.c | 9 +-
drivers/pci/xen-pcifront.c | 5 +-
drivers/xen/xen-pciback/xenbus.c | 2 +-
drivers/xen/xenbus/xenbus_client.c | 390 ++++++++++++++++++++++++++----------
include/xen/xenbus.h | 20 +-
9 files changed, 318 insertions(+), 127 deletions(-)

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 630a489..cbd13c9 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -193,7 +193,7 @@ fail:
return ERR_PTR(-ENOMEM);
}

-static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
+static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t gref,
unsigned int evtchn)
{
int err;
@@ -202,7 +202,8 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
if (blkif->irq)
return 0;

- err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring);
+ err = xenbus_map_ring_valloc(blkif->be->dev, &gref, 1,
+ &blkif->blk_ring);
if (err < 0)
return err;

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 2236c6f..2fcf75d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1246,6 +1246,7 @@ static int setup_blkring(struct xenbus_device *dev,
{
struct blkif_sring *sring;
int err;
+ grant_ref_t gref;

info->ring_ref = GRANT_INVALID_REF;

@@ -1257,13 +1258,13 @@ static int setup_blkring(struct xenbus_device *dev,
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);

- err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
+ err = xenbus_grant_ring(dev, info->ring.sring, 1, &gref);
if (err < 0) {
free_page((unsigned long)sring);
info->ring.sring = NULL;
goto fail;
}
- info->ring_ref = err;
+ info->ring_ref = gref;

err = xenbus_alloc_evtchn(dev, &info->evtchn);
if (err)
diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
index 441b44e..d3df997 100644
--- a/drivers/char/tpm/xen-tpmfront.c
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -193,6 +193,7 @@ static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
struct xenbus_transaction xbt;
const char *message = NULL;
int rv;
+ grant_ref_t gref;

priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
if (!priv->shr) {
@@ -200,11 +201,11 @@ static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
return -ENOMEM;
}

- rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr));
+ rv = xenbus_grant_ring(dev, &priv->shr, 1, &gref);
if (rv < 0)
return rv;

- priv->ring_ref = rv;
+ priv->ring_ref = gref;

rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
if (rv)
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 908e65e..8513764 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1955,7 +1955,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
int err = -ENOMEM;

err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
- tx_ring_ref, &addr);
+ &tx_ring_ref, 1, &addr);
if (err)
goto err;

@@ -1963,7 +1963,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);

err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
- rx_ring_ref, &addr);
+ &rx_ring_ref, 1, &addr);
if (err)
goto err;

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 22bcb4e..b97d26a 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1531,6 +1531,7 @@ static int setup_netfront(struct xenbus_device *dev,
struct xen_netif_tx_sring *txs;
struct xen_netif_rx_sring *rxs;
int err;
+ grant_ref_t gref;

queue->tx_ring_ref = GRANT_INVALID_REF;
queue->rx_ring_ref = GRANT_INVALID_REF;
@@ -1546,10 +1547,10 @@ static int setup_netfront(struct xenbus_device *dev,
SHARED_RING_INIT(txs);
FRONT_RING_INIT(&queue->tx, txs, PAGE_SIZE);

- err = xenbus_grant_ring(dev, virt_to_mfn(txs));
+ err = xenbus_grant_ring(dev, txs, 1, &gref);
if (err < 0)
goto grant_tx_ring_fail;
- queue->tx_ring_ref = err;
+ queue->tx_ring_ref = gref;

rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
if (!rxs) {
@@ -1560,10 +1561,10 @@ static int setup_netfront(struct xenbus_device *dev,
SHARED_RING_INIT(rxs);
FRONT_RING_INIT(&queue->rx, rxs, PAGE_SIZE);

- err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
+ err = xenbus_grant_ring(dev, rxs, 1, &gref);
if (err < 0)
goto grant_rx_ring_fail;
- queue->rx_ring_ref = err;
+ queue->rx_ring_ref = gref;

if (feature_split_evtchn)
err = setup_netfront_split(queue);
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index b1ffebe..7cfd2db 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -777,12 +777,13 @@ static int pcifront_publish_info(struct pcifront_device *pdev)
{
int err = 0;
struct xenbus_transaction trans;
+ grant_ref_t gref;

- err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
+ err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
if (err < 0)
goto out;

- pdev->gnt_ref = err;
+ pdev->gnt_ref = gref;

err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
if (err)
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index fe17c80..98bc345 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -113,7 +113,7 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
gnt_ref, remote_evtchn);

- err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
+ err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error mapping other domain page in ours.");
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index ca74410..7ef161a 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -52,17 +52,24 @@
struct xenbus_map_node {
struct list_head next;
union {
- struct vm_struct *area; /* PV */
- struct page *page; /* HVM */
+ struct {
+ struct vm_struct *area;
+ } pv;
+ struct {
+ struct page *pages[XENBUS_MAX_RING_PAGES];
+ void *addr;
+ } hvm;
};
- grant_handle_t handle;
+ grant_handle_t handles[XENBUS_MAX_RING_PAGES];
+ unsigned int nr_handles;
};

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 (*map)(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, void **vaddr);
int (*unmap)(struct xenbus_device *dev, void *vaddr);
};

@@ -355,17 +362,39 @@ static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
/**
* xenbus_grant_ring
* @dev: xenbus device
- * @ring_mfn: mfn of ring to grant
-
- * Grant access to the given @ring_mfn to the peer of the given device. Return
- * a grant reference on success, or -errno on error. On error, the device will
- * switch to XenbusStateClosing, and the error will be saved in the store.
+ * @vaddr: starting virtual address of the ring
+ * @nr_pages: number of pages to be granted
+ * @grefs: grant reference array to be filled in
+ *
+ * Grant access to the given @vaddr to the peer of the given device.
+ * Then fill in @grefs with grant references. Return a grant reference 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_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+ unsigned int nr_pages, grant_ref_t *grefs)
{
- int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
- if (err < 0)
- xenbus_dev_fatal(dev, err, "granting access to ring page");
+ int err;
+ int i, j;
+
+ for (i = 0; i < nr_pages; i++) {
+ unsigned long addr = (unsigned long)vaddr +
+ (PAGE_SIZE * i);
+ err = gnttab_grant_foreign_access(dev->otherend_id,
+ virt_to_mfn(addr), 0);
+ if (err < 0) {
+ xenbus_dev_fatal(dev, err,
+ "granting access to ring page");
+ goto fail;
+ }
+ grefs[i] = err;
+ }
+
+ return 0;
+
+fail:
+ for (j = 0; j < i; j++)
+ gnttab_end_foreign_access_ref(grefs[j], 0);
return err;
}
EXPORT_SYMBOL_GPL(xenbus_grant_ring);
@@ -419,62 +448,129 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
/**
* xenbus_map_ring_valloc
* @dev: xenbus device
- * @gnt_ref: grant reference
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant references
* @vaddr: pointer to address to be filled out by mapping
*
- * Based on Rusty Russell's skeleton driver's map_page.
- * 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.
- * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
- * or -ENOMEM on error. If an error is returned, device will switch to
+ * Map @nr_grefs pages of memory into this domain from another
+ * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs
+ * pages of virtual address space, maps the pages to that address, and
+ * sets *vaddr to that address. Returns 0 on success, and GNTST_*
+ * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL 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_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, void **vaddr)
{
- return ring_ops->map(dev, gnt_ref, vaddr);
+ return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
}
EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);

+/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
+ * long), e.g. 32-on-64. Caller is responsible for preparing the
+ * right array to feed into this function */
+static int __xenbus_map_ring(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs,
+ unsigned int nr_grefs,
+ grant_handle_t *handles,
+ phys_addr_t *addrs,
+ unsigned int flags,
+ bool *leaked)
+{
+ struct gnttab_map_grant_ref map[XENBUS_MAX_RING_PAGES];
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
+ int i, j;
+ int err = GNTST_okay;
+
+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;
+
+ for (i = 0; i < nr_grefs; i++) {
+ memset(&map[i], 0, sizeof(map[i]));
+ gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
+ dev->otherend_id);
+ handles[i] = INVALID_GRANT_HANDLE;
+ }
+
+ gnttab_batch_map(map, i);
+
+ for (i = 0; i < nr_grefs; i++) {
+ if (map[i].status != GNTST_okay) {
+ err = map[i].status;
+ xenbus_dev_fatal(dev, map[i].status,
+ "mapping in shared page %d from domain %d",
+ gnt_refs[i], dev->otherend_id);
+ goto fail;
+ } else
+ handles[i] = map[i].handle;
+ }
+
+ return GNTST_okay;
+
+fail:
+ for (i = j = 0; i < nr_grefs; i++) {
+ if (handles[i] != INVALID_GRANT_HANDLE) {
+ memset(&unmap[j], 0, sizeof(unmap[j]));
+ gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
+ GNTMAP_host_map, handles[i]);
+ j++;
+ }
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
+ BUG();
+
+ *leaked = false;
+ for (i = 0; i < j; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ *leaked = true;
+ break;
+ }
+ }
+
+ return err;
+}
+
static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
- int gnt_ref, void **vaddr)
+ grant_ref_t *gnt_refs, unsigned int nr_grefs, 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;
+ pte_t *ptes[XENBUS_MAX_RING_PAGES];
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+ int err = GNTST_okay;
+ int i;
+ bool leaked;

*vaddr = NULL;

+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;
+
+
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;

- area = alloc_vm_area(PAGE_SIZE, &pte);
+ area = alloc_vm_area(PAGE_SIZE * nr_grefs, ptes);
if (!area) {
kfree(node);
return -ENOMEM;
}

- op.host_addr = arbitrary_virt_to_machine(pte).maddr;
-
- gnttab_batch_map(&op, 1);
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;

- 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;
- }
+ err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
+ phys_addrs,
+ GNTMAP_host_map | GNTMAP_contains_pte,
+ &leaked);
+ if (err)
+ goto failed;

- node->handle = op.handle;
- node->area = area;
+ node->nr_handles = nr_grefs;
+ node->pv.area = area;

spin_lock(&xenbus_valloc_lock);
list_add(&node->next, &xenbus_valloc_pages);
@@ -482,14 +578,30 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,

*vaddr = area->addr;
return 0;
+
+failed:
+ if (!leaked)
+ free_vm_area(area);
+ else
+ pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
+
+ kfree(node);
+ return err;
}

static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
- int gnt_ref, void **vaddr)
+ grant_ref_t *gnt_ref, unsigned int nr_grefs, void **vaddr)
{
struct xenbus_map_node *node;
- int err;
+ int err, i;
void *addr;
+ bool leaked = false;
+ /* Why do we need two arrays? See comment of __xenbus_map_ring */
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+ unsigned long addrs[XENBUS_MAX_RING_PAGES];
+
+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;

*vaddr = NULL;

@@ -497,15 +609,30 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
if (!node)
return -ENOMEM;

- err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
+ err = alloc_xenballooned_pages(nr_grefs, node->hvm.pages, false /* lowmem */);
if (err)
goto out_err;

- addr = pfn_to_kaddr(page_to_pfn(node->page));
+ for (i = 0; i < nr_grefs; i++) {
+ unsigned long pfn = page_to_pfn(node->hvm.pages[i]);
+ phys_addrs[i] = (unsigned long)pfn_to_kaddr(pfn);
+ addrs[i] = (unsigned long)pfn_to_kaddr(pfn);
+ }

- err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
+ err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
+ phys_addrs, GNTMAP_host_map, &leaked);
+ node->nr_handles = nr_grefs;
if (err)
- goto out_err_free_ballooned_pages;
+ goto out_free_ballooned_pages;
+
+ addr = vmap(node->hvm.pages, nr_grefs, VM_MAP | VM_IOREMAP,
+ PAGE_KERNEL);
+ if (!addr) {
+ err = -ENOMEM;
+ goto out_xenbus_unmap_ring;
+ }
+
+ node->hvm.addr = addr;

spin_lock(&xenbus_valloc_lock);
list_add(&node->next, &xenbus_valloc_pages);
@@ -514,9 +641,17 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
*vaddr = addr;
return 0;

- out_err_free_ballooned_pages:
- free_xenballooned_pages(1, &node->page);
- out_err:
+out_xenbus_unmap_ring:
+ if (!leaked)
+ xenbus_unmap_ring(dev, node->handles, node->nr_handles,
+ addrs);
+ else
+ pr_alert("leaking %p size %u page(s)",
+ addr, nr_grefs);
+out_free_ballooned_pages:
+ if (!leaked)
+ free_xenballooned_pages(nr_grefs, node->hvm.pages);
+out_err:
kfree(node);
return err;
}
@@ -525,35 +660,37 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
/**
* xenbus_map_ring
* @dev: xenbus device
- * @gnt_ref: grant reference
- * @handle: pointer to grant handle to be filled
- * @vaddr: address to be mapped to
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant reference
+ * @handles: pointer to grant handle to be filled
+ * @vaddrs: addresses to be mapped to
+ * @leaked: fail to clean up a failed map, caller should not free vaddr
*
- * Map a page of memory into this domain from another domain's grant table.
+ * Map pages of memory into this domain from another domain's grant table.
* 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.
+ * this yourself!). It only maps in the pages to the specified address.
* Returns 0 on success, and GNTST_* (see xen/include/interface/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.
+ * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the first error message will be saved in XenStore.
+ * Further more if we fail to map the ring, caller should check @leaked.
+ * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
+ * should not free the address space of @vaddr.
*/
-int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
- grant_handle_t *handle, void *vaddr)
+int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, grant_handle_t *handles,
+ unsigned long *vaddrs, bool *leaked)
{
- struct gnttab_map_grant_ref op;
-
- gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map, gnt_ref,
- dev->otherend_id);
+ phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+ int i;

- gnttab_batch_map(&op, 1);
+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;

- 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;
+ for (i = 0; i < nr_grefs; i++)
+ phys_addrs[i] = (unsigned long)vaddrs[i];

- return op.status;
+ return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
+ phys_addrs, GNTMAP_host_map, leaked);
}
EXPORT_SYMBOL_GPL(xenbus_map_ring);

@@ -563,8 +700,7 @@ EXPORT_SYMBOL_GPL(xenbus_map_ring);
* @dev: xenbus device
* @vaddr: addr to unmap
*
- * Based on Rusty Russell's skeleton driver's unmap_page.
- * Unmap a page of memory in this domain that was imported from another domain.
+ * Unmap 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
@@ -579,20 +715,21 @@ 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,
- };
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
unsigned int level;
+ int i;
+ bool leaked = false;
+ int err;

spin_lock(&xenbus_valloc_lock);
list_for_each_entry(node, &xenbus_valloc_pages, next) {
- if (node->area->addr == vaddr) {
+ if (node->pv.area->addr == vaddr) {
list_del(&node->next);
goto found;
}
}
node = NULL;
- found:
+found:
spin_unlock(&xenbus_valloc_lock);

if (!node) {
@@ -601,22 +738,42 @@ static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
return GNTST_bad_virt_addr;
}

- op.handle = node->handle;
- op.host_addr = arbitrary_virt_to_machine(
- lookup_address((unsigned long)vaddr, &level)).maddr;
+ for (i = 0; i < node->nr_handles; i++) {
+ unsigned long addr;

- if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+ memset(&unmap[i], 0, sizeof(unmap[i]));
+ addr = (unsigned long)vaddr + (PAGE_SIZE * i);
+ unmap[i].host_addr = arbitrary_virt_to_machine(
+ lookup_address(addr, &level)).maddr;
+ unmap[i].dev_bus_addr = 0;
+ unmap[i].handle = node->handles[i];
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
BUG();

- if (op.status == GNTST_okay)
- free_vm_area(node->area);
+ err = GNTST_okay;
+ leaked = false;
+ for (i = 0; i < node->nr_handles; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ leaked = true;
+ xenbus_dev_error(dev, unmap[i].status,
+ "unmapping page at handle %d error %d",
+ node->handles[i], unmap[i].status);
+ err = unmap[i].status;
+ break;
+ }
+ }
+
+ if (!leaked)
+ free_vm_area(node->pv.area);
+
else
- xenbus_dev_error(dev, op.status,
- "unmapping page at handle %d error %d",
- node->handle, op.status);
+ pr_alert("leaking VM area %p size %u page(s)",
+ node->pv.area, node->nr_handles);

kfree(node);
- return op.status;
+ return err;
}

static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
@@ -624,10 +781,12 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
int rv;
struct xenbus_map_node *node;
void *addr;
+ unsigned long addrs[XENBUS_MAX_RING_PAGES];
+ int i;

spin_lock(&xenbus_valloc_lock);
list_for_each_entry(node, &xenbus_valloc_pages, next) {
- addr = pfn_to_kaddr(page_to_pfn(node->page));
+ addr = node->hvm.addr;
if (addr == vaddr) {
list_del(&node->next);
goto found;
@@ -643,12 +802,16 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
return GNTST_bad_virt_addr;
}

- rv = xenbus_unmap_ring(dev, node->handle, addr);
+ for (i = 0; i < node->nr_handles; i++)
+ addrs[i] = (unsigned long)pfn_to_kaddr(page_to_pfn(node->hvm.pages[i]));

+ rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
+ addrs);
if (!rv)
- free_xenballooned_pages(1, &node->page);
+ vunmap(vaddr);
else
- WARN(1, "Leaking %p\n", vaddr);
+ WARN(1, "Leaking %p, size %u page(s)\n", vaddr,
+ node->nr_handles);

kfree(node);
return rv;
@@ -657,29 +820,44 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
/**
* xenbus_unmap_ring
* @dev: xenbus device
- * @handle: grant handle
- * @vaddr: addr to unmap
+ * @handles: grant handle array
+ * @nr_handles: number of handles in the array
+ * @vaddrs: addresses to unmap
*
- * Unmap a page of memory in this domain that was imported from another domain.
+ * Unmap memory in this domain that was imported from another domain.
* Returns 0 on success and returns GNTST_* on error
* (see xen/include/interface/grant_table.h).
*/
int xenbus_unmap_ring(struct xenbus_device *dev,
- grant_handle_t handle, void *vaddr)
+ grant_handle_t *handles, unsigned int nr_handles,
+ unsigned long *vaddrs)
{
- struct gnttab_unmap_grant_ref op;
+ struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
+ int i;
+ int err;

- gnttab_set_unmap_op(&op, (unsigned long)vaddr, GNTMAP_host_map, handle);
+ if (nr_handles > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;

- if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+ for (i = 0; i < nr_handles; i++)
+ gnttab_set_unmap_op(&unmap[i], vaddrs[i],
+ GNTMAP_host_map, handles[i]);
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
BUG();

- if (op.status != GNTST_okay)
- xenbus_dev_error(dev, op.status,
- "unmapping page at handle %d error %d",
- handle, op.status);
+ err = GNTST_okay;
+ for (i = 0; i < nr_handles; i++) {
+ if (unmap[i].status != GNTST_okay) {
+ xenbus_dev_error(dev, unmap[i].status,
+ "unmapping page at handle %d error %d",
+ handles[i], unmap[i].status);
+ err = unmap[i].status;
+ break;
+ }
+ }

- return op.status;
+ return err;
}
EXPORT_SYMBOL_GPL(xenbus_unmap_ring);

diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index b78f21c..84cd1e4 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -46,6 +46,10 @@
#include <xen/interface/io/xenbus.h>
#include <xen/interface/io/xs_wire.h>

+#define XENBUS_MAX_RING_PAGE_ORDER 4
+#define XENBUS_MAX_RING_PAGES (1U << XENBUS_MAX_RING_PAGE_ORDER)
+#define INVALID_GRANT_HANDLE (~0U)
+
/* Register callback to watch this node. */
struct xenbus_watch
{
@@ -199,15 +203,19 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
const char *pathfmt, ...);

int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
-int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
-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);
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+ unsigned int nr_pages, grant_ref_t *grefs);
+int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+ unsigned int nr_grefs, void **vaddr);
+int xenbus_map_ring(struct xenbus_device *dev,
+ grant_ref_t *gnt_refs, unsigned int nr_grefs,
+ grant_handle_t *handles, unsigned long *vaddrs,
+ bool *leaked);

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);
+ grant_handle_t *handles, unsigned int nr_handles,
+ unsigned long *vaddrs);

int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
int xenbus_free_evtchn(struct xenbus_device *dev, int port);
--
1.7.10.4

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