From: David Vrabel Date: Fri, 11 Jul 2014 15:42:34 +0000 (+0100) Subject: x86/xen: safely map and unmap grant frames when in atomic context X-Git-Tag: omap-for-v3.17/fixes-against-rc2~131^2~9 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=162e371712768248a38646eefa71af38b6e0f8ce;p=pandora-kernel.git 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 Signed-off-by: Konrad Rzeszutek Wilk ---- [v2: Add comment about alloc_vm_area] [v3: Fix compile error found by 0-day bot] --- Reading git-diff-tree failed