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Message-ID: <551B2872.2010802@oracle.com>
Date: Wed, 01 Apr 2015 07:06:26 +0800
From: Bob Liu <bob.liu@...cle.com>
To: Juergen Gross <jgross@...e.com>
CC: xen-devel@...ts.xenproject.org, 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
Hi Juergen,
On 03/31/2015 08:36 PM, Juergen Gross wrote:
> 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!
>
Thanks for the reminding, I'll send an new version fix it.
Regards,
-Bob
>
> 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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