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xen: branch for v5.19-rc4

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Merge tag 'for-linus-5.19a-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - A rare deadlock in Qubes-OS between the i915 driver and Xen grant
   unmapping, solved by making the unmapping fully asynchronous

 - A bug in the Xen blkfront driver caused by incomplete error handling

 - A fix for undefined behavior (shifting a signed int by 31 bits)

 - A fix in the Xen drmfront driver avoiding a WARN()

* tag 'for-linus-5.19a-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/gntdev: Avoid blocking in unmap_grant_pages()
  drm/xen: Add missing VM_DONTEXPAND flag in mmap callback
  x86/xen: Remove undefined behavior in setup_features()
  xen-blkfront: Handle NULL gendisk
This commit is contained in:
Linus Torvalds 2022-06-24 12:22:11 -07:00
commit 2c39d612aa
5 changed files with 127 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/block/xen-blkfront.c
View File

@ -2114,9 +2114,11 @@ static void blkfront_closing(struct blkfront_info *info)
return;
/* No more blkif_request(). */
blk_mq_stop_hw_queues(info->rq);
blk_mark_disk_dead(info->gd);
set_capacity(info->gd, 0);
if (info->rq && info->gd) {
blk_mq_stop_hw_queues(info->rq);
blk_mark_disk_dead(info->gd);
set_capacity(info->gd, 0);
}
for_each_rinfo(info, rinfo, i) {
/* No more gnttab callback work. */
@ -2457,16 +2459,19 @@ static int blkfront_remove(struct xenbus_device *xbdev)
dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
del_gendisk(info->gd);
if (info->gd)
del_gendisk(info->gd);
mutex_lock(&blkfront_mutex);
list_del(&info->info_list);
mutex_unlock(&blkfront_mutex);
blkif_free(info, 0);
xlbd_release_minors(info->gd->first_minor, info->gd->minors);
blk_cleanup_disk(info->gd);
blk_mq_free_tag_set(&info->tag_set);
if (info->gd) {
xlbd_release_minors(info->gd->first_minor, info->gd->minors);
blk_cleanup_disk(info->gd);
blk_mq_free_tag_set(&info->tag_set);
}
kfree(info);
return 0;

2
drivers/gpu/drm/xen/xen_drm_front_gem.c
View File

@ -71,7 +71,7 @@ static int xen_drm_front_gem_object_mmap(struct drm_gem_object *gem_obj,
* the whole buffer.
*/
vma->vm_flags &= ~VM_PFNMAP;
vma->vm_flags |= VM_MIXEDMAP;
vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND;
vma->vm_pgoff = 0;
/*

2
drivers/xen/features.c
View File

@ -42,7 +42,7 @@ void xen_setup_features(void)
if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
break;
for (j = 0; j < 32; j++)
xen_features[i * 32 + j] = !!(fi.submap & 1<<j);
xen_features[i * 32 + j] = !!(fi.submap & 1U << j);
}
if (xen_pv_domain()) {

7
drivers/xen/gntdev-common.h
View File

@ -16,6 +16,7 @@
#include <linux/mmu_notifier.h>
#include <linux/types.h>
#include <xen/interface/event_channel.h>
#include <xen/grant_table.h>
struct gntdev_dmabuf_priv;
@ -56,6 +57,7 @@ struct gntdev_grant_map {
struct gnttab_unmap_grant_ref *unmap_ops;
struct gnttab_map_grant_ref *kmap_ops;
struct gnttab_unmap_grant_ref *kunmap_ops;
bool *being_removed;
struct page **pages;
unsigned long pages_vm_start;
@ -73,6 +75,11 @@ struct gntdev_grant_map {
/* Needed to avoid allocation in gnttab_dma_free_pages(). */
xen_pfn_t *frames;
#endif
/* Number of live grants */
atomic_t live_grants;
/* Needed to avoid allocation in __unmap_grant_pages */
struct gntab_unmap_queue_data unmap_data;
};
struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,

157
drivers/xen/gntdev.c
View File

@ -35,6 +35,7 @@
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include <xen/xen.h>
#include <xen/grant_table.h>
@ -60,10 +61,11 @@ module_param(limit, uint, 0644);
MODULE_PARM_DESC(limit,
"Maximum number of grants that may be mapped by one mapping request");
/* True in PV mode, false otherwise */
static int use_ptemod;
static int unmap_grant_pages(struct gntdev_grant_map *map,
int offset, int pages);
static void unmap_grant_pages(struct gntdev_grant_map *map,
int offset, int pages);
static struct miscdevice gntdev_miscdev;
@ -120,6 +122,7 @@ static void gntdev_free_map(struct gntdev_grant_map *map)
kvfree(map->unmap_ops);
kvfree(map->kmap_ops);
kvfree(map->kunmap_ops);
kvfree(map->being_removed);
kfree(map);
}
@ -140,10 +143,13 @@ struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]),
GFP_KERNEL);
add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
add->being_removed =
kvcalloc(count, sizeof(add->being_removed[0]), GFP_KERNEL);
if (NULL == add->grants ||
NULL == add->map_ops ||
NULL == add->unmap_ops ||
NULL == add->pages)
NULL == add->pages ||
NULL == add->being_removed)
goto err;
if (use_ptemod) {
add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]),
@ -250,9 +256,36 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
if (!refcount_dec_and_test(&map->users))
return;
if (map->pages && !use_ptemod)
if (map->pages && !use_ptemod) {
/*
* Increment the reference count. This ensures that the
* subsequent call to unmap_grant_pages() will not wind up
* re-entering itself. It *can* wind up calling
* gntdev_put_map() recursively, but such calls will be with a
* reference count greater than 1, so they will return before
* this code is reached. The recursion depth is thus limited to
* 1. Do NOT use refcount_inc() here, as it will detect that
* the reference count is zero and WARN().
*/
refcount_set(&map->users, 1);
/*
* Unmap the grants. This may or may not be asynchronous, so it
* is possible that the reference count is 1 on return, but it
* could also be greater than 1.
*/
unmap_grant_pages(map, 0, map->count);
/* Check if the memory now needs to be freed */
if (!refcount_dec_and_test(&map->users))
return;
/*
* All pages have been returned to the hypervisor, so free the
* map.
*/
}
if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
notify_remote_via_evtchn(map->notify.event);
evtchn_put(map->notify.event);
@ -283,6 +316,7 @@ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
int gntdev_map_grant_pages(struct gntdev_grant_map *map)
{
size_t alloced = 0;
int i, err = 0;
if (!use_ptemod) {
@ -331,97 +365,116 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map)
map->count);
for (i = 0; i < map->count; i++) {
if (map->map_ops[i].status == GNTST_okay)
if (map->map_ops[i].status == GNTST_okay) {
map->unmap_ops[i].handle = map->map_ops[i].handle;
else if (!err)
if (!use_ptemod)
alloced++;
} else if (!err)
err = -EINVAL;
if (map->flags & GNTMAP_device_map)
map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
if (use_ptemod) {
if (map->kmap_ops[i].status == GNTST_okay)
if (map->kmap_ops[i].status == GNTST_okay) {
if (map->map_ops[i].status == GNTST_okay)
alloced++;
map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
else if (!err)
} else if (!err)
err = -EINVAL;
}
}
atomic_add(alloced, &map->live_grants);
return err;
}
static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
int pages)
static void __unmap_grant_pages_done(int result,
struct gntab_unmap_queue_data *data)
{
int i, err = 0;
struct gntab_unmap_queue_data unmap_data;
unsigned int i;
struct gntdev_grant_map *map = data->data;
unsigned int offset = data->unmap_ops - map->unmap_ops;
if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
int pgno = (map->notify.addr >> PAGE_SHIFT);
if (pgno >= offset && pgno < offset + pages) {
/* No need for kmap, pages are in lowmem */
uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
}
}
unmap_data.unmap_ops = map->unmap_ops + offset;
unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
unmap_data.pages = map->pages + offset;
unmap_data.count = pages;
err = gnttab_unmap_refs_sync(&unmap_data);
if (err)
return err;
for (i = 0; i < pages; i++) {
if (map->unmap_ops[offset+i].status)
err = -EINVAL;
for (i = 0; i < data->count; i++) {
WARN_ON(map->unmap_ops[offset+i].status);
pr_debug("unmap handle=%d st=%d\n",
map->unmap_ops[offset+i].handle,
map->unmap_ops[offset+i].status);
map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
if (use_ptemod) {
if (map->kunmap_ops[offset+i].status)
err = -EINVAL;
WARN_ON(map->kunmap_ops[offset+i].status);
pr_debug("kunmap handle=%u st=%d\n",
map->kunmap_ops[offset+i].handle,
map->kunmap_ops[offset+i].status);
map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
}
}
return err;
/*
* Decrease the live-grant counter. This must happen after the loop to
* prevent premature reuse of the grants by gnttab_mmap().
*/
atomic_sub(data->count, &map->live_grants);
/* Release reference taken by __unmap_grant_pages */
gntdev_put_map(NULL, map);
}
static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
int pages)
static void __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
int pages)
{
int range, err = 0;
if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
int pgno = (map->notify.addr >> PAGE_SHIFT);
if (pgno >= offset && pgno < offset + pages) {
/* No need for kmap, pages are in lowmem */
uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
}
}
map->unmap_data.unmap_ops = map->unmap_ops + offset;
map->unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
map->unmap_data.pages = map->pages + offset;
map->unmap_data.count = pages;
map->unmap_data.done = __unmap_grant_pages_done;
map->unmap_data.data = map;
refcount_inc(&map->users); /* to keep map alive during async call below */
gnttab_unmap_refs_async(&map->unmap_data);
}
static void unmap_grant_pages(struct gntdev_grant_map *map, int offset,
int pages)
{
int range;
if (atomic_read(&map->live_grants) == 0)
return; /* Nothing to do */
pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
/* It is possible the requested range will have a "hole" where we
* already unmapped some of the grants. Only unmap valid ranges.
*/
while (pages && !err) {
while (pages &&
map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) {
while (pages) {
while (pages && map->being_removed[offset]) {
offset++;
pages--;
}
range = 0;
while (range < pages) {
if (map->unmap_ops[offset + range].handle ==
INVALID_GRANT_HANDLE)
if (map->being_removed[offset + range])
break;
map->being_removed[offset + range] = true;
range++;
}
err = __unmap_grant_pages(map, offset, range);
if (range)
__unmap_grant_pages(map, offset, range);
offset += range;
pages -= range;
}
return err;
}
/* ------------------------------------------------------------------ */
@ -473,7 +526,6 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
struct gntdev_grant_map *map =
container_of(mn, struct gntdev_grant_map, notifier);
unsigned long mstart, mend;
int err;
if (!mmu_notifier_range_blockable(range))
return false;
@ -494,10 +546,9 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
map->index, map->count,
map->vma->vm_start, map->vma->vm_end,
range->start, range->end, mstart, mend);
err = unmap_grant_pages(map,
unmap_grant_pages(map,
(mstart - map->vma->vm_start) >> PAGE_SHIFT,
(mend - mstart) >> PAGE_SHIFT);
WARN_ON(err);
return true;
}
@ -985,6 +1036,10 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
goto unlock_out;
if (use_ptemod && map->vma)
goto unlock_out;
if (atomic_read(&map->live_grants)) {
err = -EAGAIN;
goto unlock_out;
}
refcount_inc(&map->users);
vma->vm_ops = &gntdev_vmops;