linux_dsm_epyc7002/arch/arm/xen
David Vrabel 162e371712 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]
2014-07-14 15:28:02 -04:00
..
enlighten.c arm,arm64/xen: introduce HYPERVISOR_suspend() 2014-05-12 17:20:24 +01:00
grant-table.c x86/xen: safely map and unmap grant frames when in atomic context 2014-07-14 15:28:02 -04:00
hypercall.S arm: xen: implement multicall hypercall support. 2014-04-24 13:09:46 +01:00
Makefile xen/arm,arm64: enable SWIOTLB_XEN 2013-10-10 13:40:44 +00:00
mm.c swiotlb-xen: use xen_alloc/free_coherent_pages 2013-10-10 13:41:10 +00:00
p2m.c xen/grant-table: Refactor gnttab_[un]map_refs to avoid m2p_override 2014-03-18 14:40:19 +00:00