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| author |   Juergen Gross <jgross@suse.com> | 2018-06-18 09:36:39 +0200 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2018-06-22 08:26:42 +0200 |
| commit | c51b3c639e01f20559531eef3c5919feae23c55a (patch) | |
| tree | 8a156dfa0e0e4fca0e54a8f344d4767557e24c05 /drivers/xen/privcmd.h | |
| parent | xen/scsiback: add error handling for xenbus_printf (diff) | |
| download | linux-dev-c51b3c639e01f20559531eef3c5919feae23c55a.tar.xz linux-dev-c51b3c639e01f20559531eef3c5919feae23c55a.zip | |
xen: add new hypercall buffer mapping device
For passing arbitrary data from user land to the Xen hypervisor the
Xen tools today are using mlock()ed buffers. Unfortunately the kernel
might change access rights of such buffers for brief periods of time
e.g. for page migration or compaction, leading to access faults in the
hypervisor, as the hypervisor can't use the locks of the kernel.
In order to solve this problem add a new device node to the Xen privcmd
driver to easily allocate hypercall buffers via mmap(). The memory is
allocated in the kernel and just mapped into user space. Marked as
VM_IO the user mapping will not be subject to page migration et al.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen/privcmd.h')
| -rw-r--r-- | drivers/xen/privcmd.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/xen/privcmd.h b/drivers/xen/privcmd.h index 14facaeed36f..0dd9f8f67ee3 100644 --- a/drivers/xen/privcmd.h +++ b/drivers/xen/privcmd.h @@ -1,3 +1,6 @@ #include <linux/fs.h> extern const struct file_operations xen_privcmd_fops; +extern const struct file_operations xen_privcmdbuf_fops; + +extern struct miscdevice xen_privcmdbuf_dev; |