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| author | David Vrabel <david.vrabel@citrix.com> | 2014-07-11 16:42:34 +0100 |
|---|---|---|
| committer | David Vrabel <david.vrabel@citrix.com> | 2014-07-30 14:22:47 +0100 |
| commit | b7dd0e350e0bd4c0fddcc9b8958342700b00b168 (patch) | |
| tree | f69ea88b9e9f5e234d5c5d2f3f0ceaa22d3049b8 /arch/arm/xen/grant-table.c | |
| parent | fb9a0c443691ceaab3daba966bbbd9f5ff3aa26f (diff) | |
| download | linux-b7dd0e350e0bd4c0fddcc9b8958342700b00b168.tar.gz linux-b7dd0e350e0bd4c0fddcc9b8958342700b00b168.tar.bz2 linux-b7dd0e350e0bd4c0fddcc9b8958342700b00b168.zip | |
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 (which ensures
that the required page tables are pre-allocated).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch/arm/xen/grant-table.c')
| -rw-r--r-- | arch/arm/xen/grant-table.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm/xen/grant-table.c b/arch/arm/xen/grant-table.c index 859a9bb002d5..91cf08ba1e95 100644 --- a/arch/arm/xen/grant-table.c +++ b/arch/arm/xen/grant-table.c @@ -51,3 +51,8 @@ int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, { return -ENOSYS; } + +int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) +{ + return 0; +} |