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| author | David Vrabel <david.vrabel@citrix.com> | 2014-07-11 19:42:34 +0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2014-07-14 23:28:02 +0400 |
| commit | 162e371712768248a38646eefa71af38b6e0f8ce (patch) | |
| tree | 899b44d49c7b6cce18e831bb32deb4496d0e016e /include/xen | |
| parent | a2c5ae65addb122270cf4115c92039c5b8bf15b9 (diff) | |
| download | linux-162e371712768248a38646eefa71af38b6e0f8ce.tar.xz | |
x86/xen: safely map and unmap grant frames when in atomic context
arch_gnttab_map_frames() and arch_gnttab_unmap_frames() are called in
atomic context but were calling alloc_vm_area() which might sleep.
Also, if a driver attempts to allocate a grant ref from an interrupt
and the table needs expanding, then the CPU may already by in lazy MMU
mode and apply_to_page_range() will BUG when it tries to re-enable
lazy MMU mode.
These two functions are only used in PV guests.
Introduce arch_gnttab_init() to allocates the virtual address space in
advance.
Avoid the use of apply_to_page_range() by using saving and using the
array of PTE addresses from the alloc_vm_area() call.
N.B. 'alloc_vm_area' pre-allocates the pagetable so there is no need
to worry about having to do a PGD/PUD/PMD walk (like apply_to_page_range
does) and we can instead do set_pte.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
----
[v2: Add comment about alloc_vm_area]
[v3: Fix compile error found by 0-day bot]
Diffstat (limited to 'include/xen')
| -rw-r--r-- | include/xen/grant_table.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index a5af2a26d94f..5c1aba154b64 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -170,6 +170,7 @@ gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr, unmap->dev_bus_addr = 0; } +int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status); int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes, unsigned long max_nr_gframes, void **__shared); |