Commit 92937241 authored by Boris Ostrovsky's avatar Boris Ostrovsky
Browse files

xen/gntdev: Do not use mm notifiers with autotranslating guests 



Commit d3eeb1d7 ("xen/gntdev: use mmu_interval_notifier_insert")
missed a test for use_ptemod when calling mmu_interval_read_begin(). Fix
that.

Fixes: d3eeb1d7 ("xen/gntdev: use mmu_interval_notifier_insert")
CC: stable@vger.kernel.org # 5.5
Reported-by: default avatarIlpo Järvinen <ilpo.jarvinen@cs.helsinki.fi>
Tested-by: default avatarIlpo Järvinen <ilpo.jarvinen@cs.helsinki.fi>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Acked-by: default avatarJuergen Gross <jgross@suse.com>
parent eda4eabf

drivers/xen/gntdev.c

+12 −12
Original line number Diff line number Diff line
@@ -1006,19 +1006,19 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) 
	}

	mutex_unlock(&priv->lock);



	if (use_ptemod) {

		/*

	 * gntdev takes the address of the PTE in find_grant_ptes() and passes

	 * it to the hypervisor in gntdev_map_grant_pages(). The purpose of

	 * the notifier is to prevent the hypervisor pointer to the PTE from

	 * going stale.

		 * gntdev takes the address of the PTE in find_grant_ptes() and

		 * passes it to the hypervisor in gntdev_map_grant_pages(). The

		 * purpose of the notifier is to prevent the hypervisor pointer

		 * to the PTE from going stale.

		 *

	 * Since this vma's mappings can't be touched without the mmap_sem,

	 * and we are holding it now, there is no need for the notifier_range

	 * locking pattern.

		 * Since this vma's mappings can't be touched without the

		 * mmap_sem, and we are holding it now, there is no need for

		 * the notifier_range locking pattern.

		 */

		mmu_interval_read_begin(&map->notifier);



	if (use_ptemod) {

		map->pages_vm_start = vma->vm_start;

		err = apply_to_page_range(vma->vm_mm, vma->vm_start,

					  vma->vm_end - vma->vm_start,

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