linux/arch/powerpc/mm
Alexey Kardashevskiy 15b244a88e powerpc/mmu: Add userspace-to-physical addresses translation cache
We are adding support for DMA memory pre-registration to be used in
conjunction with VFIO. The idea is that the userspace which is going to
run a guest may want to pre-register a user space memory region so
it all gets pinned once and never goes away. Having this done,
a hypervisor will not have to pin/unpin pages on every DMA map/unmap
request. This is going to help with multiple pinning of the same memory.

Another use of it is in-kernel real mode (mmu off) acceleration of
DMA requests where real time translation of guest physical to host
physical addresses is non-trivial and may fail as linux ptes may be
temporarily invalid. Also, having cached host physical addresses
(compared to just pinning at the start and then walking the page table
again on every H_PUT_TCE), we can be sure that the addresses which we put
into TCE table are the ones we already pinned.

This adds a list of memory regions to mm_context_t. Each region consists
of a header and a list of physical addresses. This adds API to:
1. register/unregister memory regions;
2. do final cleanup (which puts all pre-registered pages);
3. do userspace to physical address translation;
4. manage usage counters; multiple registration of the same memory
is allowed (once per container).

This implements 2 counters per registered memory region:
- @mapped: incremented on every DMA mapping; decremented on unmapping;
initialized to 1 when a region is just registered; once it becomes zero,
no more mappings allowe;
- @used: incremented on every "register" ioctl; decremented on
"unregister"; unregistration is allowed for DMA mapped regions unless
it is the very last reference. For the very last reference this checks
that the region is still mapped and returns -EBUSY so the userspace
gets to know that memory is still pinned and unregistration needs to
be retried; @used remains 1.

Host physical addresses are stored in vmalloc'ed array. In order to
access these in the real mode (mmu off), there is a real_vmalloc_addr()
helper. In-kernel acceleration patchset will move it from KVM to MMU code.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-11 15:16:54 +10:00
..
40x_mmu.c memblock: Remove rmo_size, burry it in arch/powerpc where it belongs 2010-08-05 12:56:08 +10:00
44x_mmu.c powerpc: Delete __cpuinit usage from all users 2013-07-01 11:10:36 +10:00
Makefile powerpc/mmu: Add userspace-to-physical addresses translation cache 2015-06-11 15:16:54 +10:00
copro_fault.c cxl: Move include file cxl.h -> cxl-base.h 2015-06-03 13:27:19 +10:00
dma-noncoherent.c powerpc: Fix compile errors with STRICT_MM_TYPECHECKS enabled 2015-04-10 20:02:47 +10:00
fault.c ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT 2015-02-12 18:54:08 -08:00
fsl_booke_mmu.c powerpc: Fix compile errors with STRICT_MM_TYPECHECKS enabled 2015-04-10 20:02:47 +10:00
hash_low_32.S powerpc: Use CURRENT_THREAD_INFO instead of open coded assembly 2012-07-11 14:18:22 +10:00
hash_low_64.S powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault 2014-12-05 16:26:15 +11:00
hash_native_64.c cxl: Move include file cxl.h -> cxl-base.h 2015-06-03 13:27:19 +10:00
hash_utils_64.c powerpc/mm: Add trace point for tracking hash pte fault 2015-06-10 14:06:29 +10:00
highmem.c mm: fix race in kunmap_atomic() 2010-10-27 18:03:05 -07:00
hugepage-hash64.c powerpc: Fix compile errors with STRICT_MM_TYPECHECKS enabled 2015-04-10 20:02:47 +10:00
hugetlbpage-book3e.c powerpc: Replace __get_cpu_var uses 2014-11-03 12:12:32 +11:00
hugetlbpage-hash64.c powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault 2014-12-05 16:26:15 +11:00
hugetlbpage.c powerpc/mm/thp: Return pte address if we find trans_splitting. 2015-04-17 11:23:40 +10:00
icswx.c powerpc: Fix typo "CONFIG_ICSWX_PID" 2013-04-18 13:03:54 +10:00
icswx.h powerpc/icswx: Fix race condition with IPI setting ACOP 2012-03-07 17:06:09 +11:00
icswx_pid.c powerpc: Split ICSWX ACOP and PID processing 2011-11-25 14:11:27 +11:00
init_32.c powerpc: Remove superfluous bootmem includes 2014-11-10 09:59:26 +11:00
init_64.c powerpc/mm: Free string after creating kmem cache 2015-03-26 15:23:17 +11:00
mem.c powerpc: Replace mem_init_done with slab_is_available() 2015-04-10 20:02:48 +10:00
mmap.c mm: expose arch_mmap_rnd when available 2015-04-14 16:49:05 -07:00
mmu_context_hash32.c powerpc: Remove power3 from comments 2014-07-28 14:10:26 +10:00
mmu_context_hash64.c powerpc/mmu: Add userspace-to-physical addresses translation cache 2015-06-11 15:16:54 +10:00
mmu_context_iommu.c powerpc/mmu: Add userspace-to-physical addresses translation cache 2015-06-11 15:16:54 +10:00
mmu_context_nohash.c powerpc/8xx: reduce pressure on TLB due to context switches 2015-01-29 21:51:06 -06:00
mmu_decl.h powerpc/mm: Change setbat() to take a pgprot_t rather than flags 2015-04-07 17:15:13 +10:00
numa.c powerpc/numa: Reset node_possible_map to only node_online_map 2015-03-23 13:25:53 +11:00
pgtable.c mm: convert p[te|md]_numa users to p[te|md]_protnone_numa 2015-02-12 18:54:08 -08:00
pgtable_32.c powerpc: Replace mem_init_done with slab_is_available() 2015-04-10 20:02:48 +10:00
pgtable_64.c powerpc: Replace mem_init_done with slab_is_available() 2015-04-10 20:02:48 +10:00
ppc_mmu_32.c powerpc/mm: Change setbat() to take a pgprot_t rather than flags 2015-04-07 17:15:13 +10:00
slb.c powerpc/cell: Move data segment faulting code out of cell platform 2014-10-08 20:14:55 +11:00
slb_low.S Merge remote-tracking branch 'anton/abiv2' into next 2014-05-05 20:57:12 +10:00
slice.c powerpc: Remove some unused functions 2015-01-28 15:00:24 +11:00
subpage-prot.c arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma() 2015-02-11 17:06:06 -08:00
tlb_hash32.c powerpc: include export.h for files using EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:38 -04:00
tlb_hash64.c powerpc: Fix compile errors with STRICT_MM_TYPECHECKS enabled 2015-04-10 20:02:47 +10:00
tlb_low_64e.S powerpc/e6500: Work around erratum A-008139 2014-07-29 19:26:29 -05:00
tlb_nohash.c powerpc/mm: Warn on flushing tlb page in kernel context 2015-02-04 13:19:27 +11:00
tlb_nohash_low.S powerpc/fsl_booke: smp support for booting a relocatable kernel above 64M 2014-01-09 17:52:18 -06:00
vphn.c powerpc/vphn: parsing code rewrite 2015-03-18 10:48:59 +11:00
vphn.h powerpc/vphn: parsing code rewrite 2015-03-18 10:48:59 +11:00