mirror of https://gitee.com/openkylin/linux.git
xen/xenbus: avoid large structs and arrays on the stack
xenbus_map_ring_valloc() and its sub-functions are putting quite large structs and arrays on the stack. This is problematic at runtime, but might also result in build failures (e.g. with clang due to the option -Werror,-Wframe-larger-than=... used). Fix that by moving most of the data from the stack into a dynamically allocated struct. Performance is no issue here, as xenbus_map_ring_valloc() is used only when adding a new PV device to a backend driver. While at it move some duplicated code from pv/hvm specific mapping functions to the single caller. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20200701121638.19840-2-jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Juergen Gross
Boris Ostrovsky
parent
caef73cf20
commit
3848e4e0a3
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@ -69,11 +69,27 @@ struct xenbus_map_node {
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unsigned int nr_handles;
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};
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struct map_ring_valloc {
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struct xenbus_map_node *node;
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/* Why do we need two arrays? See comment of __xenbus_map_ring */
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union {
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unsigned long addrs[XENBUS_MAX_RING_GRANTS];
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pte_t *ptes[XENBUS_MAX_RING_GRANTS];
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};
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phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
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struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
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struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
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unsigned int idx; /* HVM only. */
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};
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static DEFINE_SPINLOCK(xenbus_valloc_lock);
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static LIST_HEAD(xenbus_valloc_pages);
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struct xenbus_ring_ops {
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int (*map)(struct xenbus_device *dev,
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int (*map)(struct xenbus_device *dev, struct map_ring_valloc *info,
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grant_ref_t *gnt_refs, unsigned int nr_grefs,
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void **vaddr);
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int (*unmap)(struct xenbus_device *dev, void *vaddr);
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@ -449,12 +465,32 @@ int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
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unsigned int nr_grefs, void **vaddr)
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{
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int err;
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struct map_ring_valloc *info;
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*vaddr = NULL;
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if (nr_grefs > XENBUS_MAX_RING_GRANTS)
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return -EINVAL;
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info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return -ENOMEM;
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info->node = kzalloc(sizeof(*info->node), GFP_KERNEL);
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if (!info->node) {
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err = -ENOMEM;
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goto out;
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}
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err = ring_ops->map(dev, info, gnt_refs, nr_grefs, vaddr);
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err = ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
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/* Some hypervisors are buggy and can return 1. */
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if (err > 0)
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err = GNTST_general_error;
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out:
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kfree(info->node);
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kfree(info);
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return err;
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}
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EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
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@ -466,12 +502,10 @@ static int __xenbus_map_ring(struct xenbus_device *dev,
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grant_ref_t *gnt_refs,
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unsigned int nr_grefs,
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grant_handle_t *handles,
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phys_addr_t *addrs,
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struct map_ring_valloc *info,
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unsigned int flags,
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bool *leaked)
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{
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struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
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struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
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int i, j;
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int err = GNTST_okay;
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@ -479,23 +513,22 @@ static int __xenbus_map_ring(struct xenbus_device *dev,
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return -EINVAL;
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for (i = 0; i < nr_grefs; i++) {
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memset(&map[i], 0, sizeof(map[i]));
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gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
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dev->otherend_id);
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gnttab_set_map_op(&info->map[i], info->phys_addrs[i], flags,
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gnt_refs[i], dev->otherend_id);
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handles[i] = INVALID_GRANT_HANDLE;
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}
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gnttab_batch_map(map, i);
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gnttab_batch_map(info->map, i);
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for (i = 0; i < nr_grefs; i++) {
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if (map[i].status != GNTST_okay) {
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err = map[i].status;
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xenbus_dev_fatal(dev, map[i].status,
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if (info->map[i].status != GNTST_okay) {
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err = info->map[i].status;
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xenbus_dev_fatal(dev, info->map[i].status,
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"mapping in shared page %d from domain %d",
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gnt_refs[i], dev->otherend_id);
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goto fail;
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} else
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handles[i] = map[i].handle;
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handles[i] = info->map[i].handle;
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}
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return GNTST_okay;
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@ -503,19 +536,19 @@ static int __xenbus_map_ring(struct xenbus_device *dev,
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fail:
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for (i = j = 0; i < nr_grefs; i++) {
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if (handles[i] != INVALID_GRANT_HANDLE) {
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memset(&unmap[j], 0, sizeof(unmap[j]));
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gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
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gnttab_set_unmap_op(&info->unmap[j],
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info->phys_addrs[i],
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GNTMAP_host_map, handles[i]);
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j++;
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}
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}
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if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
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if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, info->unmap, j))
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BUG();
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*leaked = false;
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for (i = 0; i < j; i++) {
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if (unmap[i].status != GNTST_okay) {
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if (info->unmap[i].status != GNTST_okay) {
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*leaked = true;
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break;
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}
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@ -566,21 +599,12 @@ static int xenbus_unmap_ring(struct xenbus_device *dev, grant_handle_t *handles,
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return err;
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}
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struct map_ring_valloc_hvm
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{
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unsigned int idx;
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/* Why do we need two arrays? See comment of __xenbus_map_ring */
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phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
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unsigned long addrs[XENBUS_MAX_RING_GRANTS];
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};
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static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
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unsigned int goffset,
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unsigned int len,
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void *data)
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{
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struct map_ring_valloc_hvm *info = data;
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struct map_ring_valloc *info = data;
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unsigned long vaddr = (unsigned long)gfn_to_virt(gfn);
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info->phys_addrs[info->idx] = vaddr;
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@ -589,39 +613,28 @@ static void xenbus_map_ring_setup_grant_hvm(unsigned long gfn,
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info->idx++;
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}
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static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
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grant_ref_t *gnt_ref,
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unsigned int nr_grefs,
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void **vaddr)
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static int xenbus_map_ring_hvm(struct xenbus_device *dev,
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struct map_ring_valloc *info,
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grant_ref_t *gnt_ref,
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unsigned int nr_grefs,
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void **vaddr)
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{
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struct xenbus_map_node *node;
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struct xenbus_map_node *node = info->node;
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int err;
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void *addr;
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bool leaked = false;
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struct map_ring_valloc_hvm info = {
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.idx = 0,
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};
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unsigned int nr_pages = XENBUS_PAGES(nr_grefs);
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if (nr_grefs > XENBUS_MAX_RING_GRANTS)
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return -EINVAL;
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*vaddr = NULL;
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node = kzalloc(sizeof(*node), GFP_KERNEL);
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if (!node)
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return -ENOMEM;
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err = alloc_xenballooned_pages(nr_pages, node->hvm.pages);
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if (err)
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goto out_err;
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gnttab_foreach_grant(node->hvm.pages, nr_grefs,
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xenbus_map_ring_setup_grant_hvm,
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&info);
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info);
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err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
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info.phys_addrs, GNTMAP_host_map, &leaked);
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info, GNTMAP_host_map, &leaked);
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node->nr_handles = nr_grefs;
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if (err)
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@ -641,11 +654,13 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
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spin_unlock(&xenbus_valloc_lock);
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*vaddr = addr;
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info->node = NULL;
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return 0;
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out_xenbus_unmap_ring:
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if (!leaked)
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xenbus_unmap_ring(dev, node->handles, nr_grefs, info.addrs);
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xenbus_unmap_ring(dev, node->handles, nr_grefs, info->addrs);
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else
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pr_alert("leaking %p size %u page(s)",
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addr, nr_pages);
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@ -653,7 +668,6 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
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if (!leaked)
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free_xenballooned_pages(nr_pages, node->hvm.pages);
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out_err:
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kfree(node);
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return err;
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}
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@ -676,40 +690,30 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
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EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
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#ifdef CONFIG_XEN_PV
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static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
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grant_ref_t *gnt_refs,
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unsigned int nr_grefs,
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void **vaddr)
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static int xenbus_map_ring_pv(struct xenbus_device *dev,
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struct map_ring_valloc *info,
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grant_ref_t *gnt_refs,
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unsigned int nr_grefs,
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void **vaddr)
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{
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struct xenbus_map_node *node;
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struct xenbus_map_node *node = info->node;
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struct vm_struct *area;
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pte_t *ptes[XENBUS_MAX_RING_GRANTS];
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phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];
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int err = GNTST_okay;
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int i;
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bool leaked;
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*vaddr = NULL;
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if (nr_grefs > XENBUS_MAX_RING_GRANTS)
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return -EINVAL;
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node = kzalloc(sizeof(*node), GFP_KERNEL);
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if (!node)
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return -ENOMEM;
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area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, ptes);
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area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, info->ptes);
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if (!area) {
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kfree(node);
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return -ENOMEM;
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}
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for (i = 0; i < nr_grefs; i++)
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phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
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info->phys_addrs[i] =
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arbitrary_virt_to_machine(info->ptes[i]).maddr;
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err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
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phys_addrs,
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GNTMAP_host_map | GNTMAP_contains_pte,
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info, GNTMAP_host_map | GNTMAP_contains_pte,
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&leaked);
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if (err)
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goto failed;
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@ -722,6 +726,8 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
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spin_unlock(&xenbus_valloc_lock);
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*vaddr = area->addr;
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info->node = NULL;
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return 0;
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failed:
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@ -730,11 +736,10 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
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else
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pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
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kfree(node);
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return err;
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}
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static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
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static int xenbus_unmap_ring_pv(struct xenbus_device *dev, void *vaddr)
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{
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struct xenbus_map_node *node;
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struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];
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@ -798,12 +803,12 @@ static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
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}
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static const struct xenbus_ring_ops ring_ops_pv = {
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.map = xenbus_map_ring_valloc_pv,
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.unmap = xenbus_unmap_ring_vfree_pv,
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.map = xenbus_map_ring_pv,
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.unmap = xenbus_unmap_ring_pv,
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};
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#endif
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struct unmap_ring_vfree_hvm
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struct unmap_ring_hvm
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{
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unsigned int idx;
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unsigned long addrs[XENBUS_MAX_RING_GRANTS];
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@ -814,19 +819,19 @@ static void xenbus_unmap_ring_setup_grant_hvm(unsigned long gfn,
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unsigned int len,
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void *data)
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{
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struct unmap_ring_vfree_hvm *info = data;
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struct unmap_ring_hvm *info = data;
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info->addrs[info->idx] = (unsigned long)gfn_to_virt(gfn);
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info->idx++;
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}
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static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
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static int xenbus_unmap_ring_hvm(struct xenbus_device *dev, void *vaddr)
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{
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int rv;
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struct xenbus_map_node *node;
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void *addr;
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struct unmap_ring_vfree_hvm info = {
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struct unmap_ring_hvm info = {
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.idx = 0,
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};
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unsigned int nr_pages;
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@ -887,8 +892,8 @@ enum xenbus_state xenbus_read_driver_state(const char *path)
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EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
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static const struct xenbus_ring_ops ring_ops_hvm = {
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.map = xenbus_map_ring_valloc_hvm,
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.unmap = xenbus_unmap_ring_vfree_hvm,
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.map = xenbus_map_ring_hvm,
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.unmap = xenbus_unmap_ring_hvm,
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};
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void __init xenbus_ring_ops_init(void)
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