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Date: Tue, 31 Mar 2015 14:36:43 +0200
From: Juergen Gross <jgross@...e.com>
To: Bob Liu <bob.liu@...cle.com>, xen-devel@...ts.xenproject.org
CC: paul.durrant@...rix.com, david.vrabel@...rix.com,
roger.pau@...rix.com, linux-kernel@...r.kernel.org,
konrad.wilk@...cle.com, Wei Liu <wei.liu2@...rix.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>
Subject: Re: [PATCH RESEND 1/2] xenbus_client: Extend interface to support
multi-page ring
On 03/31/2015 02:15 PM, Bob Liu wrote:
> From: Wei Liu <wei.liu2@...rix.com>
>
> 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
What about pvscsi drivers?
They are affected, too!
Juergen
>
> 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@...rix.com>
> Signed-off-by: Paul Durrant <paul.durrant@...rix.com>
> Signed-off-by: Bob Liu <bob.liu@...cle.com>
> Cc: Konrad Wilk <konrad.wilk@...cle.com>
> Cc: David Vrabel <david.vrabel@...rix.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
> ---
> drivers/block/xen-blkback/xenbus.c | 5 +-
> drivers/block/xen-blkfront.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 | 387 +++++++++++++++++++++++++++----------
> include/xen/xenbus.h | 20 +-
> 8 files changed, 317 insertions(+), 120 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
> index e3afe97..ff30259 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 37779e4..2c61cf8 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -1245,6 +1245,7 @@ static int setup_blkring(struct xenbus_device *dev,
> struct blkfront_info *info)
> {
> struct blkif_sring *sring;
> + grant_ref_t gref;
> int err;
>
> 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/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index 997cf09..865203f 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1782,7 +1782,7 @@ 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;
>
> @@ -1790,7 +1790,7 @@ 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 e9b960f..13f5e7f 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -1486,6 +1486,7 @@ static int setup_netfront(struct xenbus_device *dev,
> {
> struct xen_netif_tx_sring *txs;
> struct xen_netif_rx_sring *rxs;
> + grant_ref_t gref;
> int err;
>
> queue->tx_ring_ref = GRANT_INVALID_REF;
> @@ -1502,10 +1503,10 @@ 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) {
> @@ -1516,10 +1517,10 @@ 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..96b2011 100644
> --- a/drivers/xen/xenbus/xenbus_client.c
> +++ b/drivers/xen/xenbus/xenbus_client.c
> @@ -52,17 +52,25 @@
> 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 +363,39 @@ 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 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_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 +449,130 @@ 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;
> + for (i = 0; i < nr_grefs; i++)
> + phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
>
> - gnttab_batch_map(&op, 1);
> -
> - 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 +580,33 @@ 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 i;
> int err;
> 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 +614,32 @@ 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, nr_grefs, node->handles,
> + phys_addrs, GNTMAP_host_map, &leaked);
> + node->nr_handles = nr_grefs;
>
> - err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
> 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);
> @@ -514,8 +648,16 @@ 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_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 +667,37 @@ 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);
>
> @@ -579,14 +723,15 @@ 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;
> }
> @@ -601,22 +746,41 @@ 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;
> +
> + 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, &op, 1))
> + 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 +788,12 @@ 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 +809,16 @@ 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 +827,44 @@ 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 b0f1c9e..289c0b5 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);
>
--
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