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authorDavid Vrabel <david.vrabel@citrix.com>2014-07-11 19:42:34 +0400
committerDavid Vrabel <david.vrabel@citrix.com>2014-07-30 17:22:47 +0400
commitb7dd0e350e0bd4c0fddcc9b8958342700b00b168 (patch)
treef69ea88b9e9f5e234d5c5d2f3f0ceaa22d3049b8 /include/xen
parentfb9a0c443691ceaab3daba966bbbd9f5ff3aa26f (diff)
downloadlinux-b7dd0e350e0bd4c0fddcc9b8958342700b00b168.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 (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 'include/xen')
-rw-r--r--include/xen/grant_table.h1
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);