* [PATCH RFC 1/2] xen/page_alloc: Add size_align parameter to provide MFNs which are size aligned.
2016-11-30 4:39 [PATCH RFC] Add size alignment to page allocator Konrad Rzeszutek Wilk
@ 2016-11-30 4:39 ` Konrad Rzeszutek Wilk
2016-11-30 9:30 ` Jan Beulich
2016-11-30 4:39 ` [PATCH RFC 2/2] xen-swiotlb: Provide size aligned DMA addresses Konrad Rzeszutek Wilk
1 sibling, 1 reply; 6+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-11-30 4:39 UTC (permalink / raw)
To: xen-devel, konrad, boris.ostrovsky, jgross
Cc: sstabellini, wei.liu2, martin.petersen, George.Dunlap,
andrew.cooper3, ian.jackson, tim, jbeulich
This is to support the requirement that exists in PV dom0
when doing DMA requests:
"dma_alloc_coherent()
[...]
The CPU virtual address and the DMA address are both guaranteed to be
aligned to the smallest PAGE_SIZE order which is greater than or equal
to the requested size. This invariant exists (for example) to guarantee
that if you allocate a chunk which is smaller than or equal to 64
kilobytes, the extent of the buffer you receive will not cross a 64K
boundary."
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
xen/common/memory.c | 3 +++
xen/common/page_alloc.c | 22 +++++++++++++++++++++-
xen/include/public/memory.h | 2 ++
xen/include/xen/mm.h | 2 ++
4 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/xen/common/memory.c b/xen/common/memory.c
index 21797ca..a4c0c54 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -475,6 +475,9 @@ static long memory_exchange(XEN_GUEST_HANDLE_PARAM(xen_memory_exchange_t) arg)
(BITS_PER_LONG+PAGE_SHIFT)));
memflags |= MEMF_node(XENMEMF_get_node(exch.out.mem_flags));
+ if ( XENMEMF_align_size & exch.out.mem_flags && is_hardware_domain(d) )
+ memflags |= MEMF_size_align;
+
for ( i = (exch.nr_exchanged >> in_chunk_order);
i < (exch.in.nr_extents >> in_chunk_order);
i++ )
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index ae2476d..e43f52f 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -738,7 +738,7 @@ static struct page_info *alloc_heap_pages(
* Others try tmem pools then fail. This is a workaround until all
* post-dom0-creation-multi-page allocations can be eliminated.
*/
- if ( ((order == 0) || (order >= 9)) &&
+ if ( ((order == 0) || (order >= 9)) && !(memflags & MEMF_size_align) &&
(total_avail_pages <= midsize_alloc_zone_pages) &&
tmem_freeable_pages() )
goto try_tmem;
@@ -752,14 +752,34 @@ static struct page_info *alloc_heap_pages(
{
zone = zone_hi;
do {
+ struct page_info *old = NULL;
+
/* Check if target node can support the allocation. */
if ( !avail[node] || (avail[node][zone] < request) )
continue;
/* Find smallest order which can satisfy the request. */
for ( j = order; j <= MAX_ORDER; j++ )
+ {
+ next_page:
if ( (pg = page_list_remove_head(&heap(node, zone, j))) )
+ {
+ if ( memflags & MEMF_size_align )
+ {
+ if (pg == old)
+ continue;
+
+ if ( (page_to_mfn(pg) % request ) == 0 )
+ goto found;
+
+ page_list_add_tail(pg, &heap(node, zone, j));
+ old = pg;
+ pg = NULL;
+ goto next_page;
+ }
goto found;
+ }
+ }
} while ( zone-- > zone_lo ); /* careful: unsigned zone may wrap */
if ( (memflags & MEMF_exact_node) && req_node != NUMA_NO_NODE )
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index 5bf840f..311e7d8 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -58,6 +58,8 @@
#define XENMEMF_exact_node(n) (XENMEMF_node(n) | XENMEMF_exact_node_request)
/* Flag to indicate the node specified is virtual node */
#define XENMEMF_vnode (1<<18)
+/* Flag to indicate the allocation to be size aligned. */
+#define XENMEMF_align_size (1U<<19)
#endif
struct xen_memory_reservation {
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
index 76fbb82..c505170 100644
--- a/xen/include/xen/mm.h
+++ b/xen/include/xen/mm.h
@@ -224,6 +224,8 @@ struct npfec {
#define MEMF_no_owner (1U<<_MEMF_no_owner)
#define _MEMF_no_tlbflush 6
#define MEMF_no_tlbflush (1U<<_MEMF_no_tlbflush)
+#define _MEMF_size_align 7
+#define MEMF_size_align (1U<<_MEMF_size_align)
#define _MEMF_node 8
#define MEMF_node_mask ((1U << (8 * sizeof(nodeid_t))) - 1)
#define MEMF_node(n) ((((n) + 1) & MEMF_node_mask) << _MEMF_node)
--
2.7.4
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^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH RFC 2/2] xen-swiotlb: Provide size aligned DMA addresses.
2016-11-30 4:39 [PATCH RFC] Add size alignment to page allocator Konrad Rzeszutek Wilk
2016-11-30 4:39 ` [PATCH RFC 1/2] xen/page_alloc: Add size_align parameter to provide MFNs which are size aligned Konrad Rzeszutek Wilk
@ 2016-11-30 4:39 ` Konrad Rzeszutek Wilk
1 sibling, 0 replies; 6+ messages in thread
From: Konrad Rzeszutek Wilk @ 2016-11-30 4:39 UTC (permalink / raw)
To: xen-devel, konrad, boris.ostrovsky, jgross
Cc: sstabellini, wei.liu2, martin.petersen, George.Dunlap,
andrew.cooper3, ian.jackson, tim, jbeulich
The dma_alloc_coherent() API specifies that:
[...]
The CPU virtual address and the DMA address are both guaranteed to be
aligned to the smallest PAGE_SIZE order which is greater than or equal
to the requested size. This invariant exists (for example) to guarantee
that if you allocate a chunk which is smaller than or equal to 64
kilobytes, the extent of the buffer you receive will not cross a 64K
boundary."
This change, along with the XENMEMF_align_size in the hypervisor
allows us to provide DMA buffers that are size aligned.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/mmu.c | 12 +++++++-----
drivers/xen/swiotlb-xen.c | 4 ++--
include/xen/interface/memory.h | 10 ++++++++++
include/xen/xen-ops.h | 2 +-
4 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 7d5afdb..07e5a97 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2577,7 +2577,8 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
unsigned long extents_out,
unsigned int order_out,
unsigned long *mfns_out,
- unsigned int address_bits)
+ unsigned int address_bits,
+ bool size_align)
{
long rc;
int success;
@@ -2599,7 +2600,8 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
};
BUG_ON(extents_in << order_in != extents_out << order_out);
-
+ if (size_align)
+ exchange.out.address_bits |= XENMEMF_align_size;
rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
success = (exchange.nr_exchanged == extents_in);
@@ -2611,7 +2613,7 @@ static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
- dma_addr_t *dma_handle)
+ dma_addr_t *dma_handle, bool size_align)
{
unsigned long *in_frames = discontig_frames, out_frame;
unsigned long flags;
@@ -2641,7 +2643,7 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
out_frame = virt_to_pfn(vstart);
success = xen_exchange_memory(1UL << order, 0, in_frames,
1, order, &out_frame,
- address_bits);
+ address_bits, size_align);
/* 3. Map the new extent in place of old pages. */
if (success)
@@ -2682,7 +2684,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
/* 3. Do the exchange for non-contiguous MFNs. */
success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
- 0, out_frames, 0);
+ 0, out_frames, 0, false);
/* 4. Map new pages in place of old pages. */
if (success)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 87e6035..4996685 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -173,7 +173,7 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
rc = xen_create_contiguous_region(
p + (i << IO_TLB_SHIFT),
get_order(slabs << IO_TLB_SHIFT),
- dma_bits, &dma_handle);
+ dma_bits, &dma_handle, false);
} while (rc && dma_bits++ < max_dma_bits);
if (rc)
return rc;
@@ -334,7 +334,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
*dma_handle = dev_addr;
else {
if (xen_create_contiguous_region(phys, order,
- fls64(dma_mask), dma_handle) != 0) {
+ fls64(dma_mask), dma_handle, true) != 0) {
xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
return NULL;
}
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index 9aa8988..b98271f 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -19,6 +19,16 @@
#define XENMEM_increase_reservation 0
#define XENMEM_decrease_reservation 1
#define XENMEM_populate_physmap 6
+/*
+ * Maximum # bits addressable by the user of the allocated region (e.g., I/O
+ * devices often have a 32-bit limitation even in 64-bit systems). If zero
+ * then the user has no addressing restriction. This field is not used by
+ * XENMEM_decrease_reservation.
+ */
+
+/* Flag to indicate the allocation to be size aligned. */
+#define XENMEMF_align_size (1U<<19)
+
struct xen_memory_reservation {
/*
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index b5486e6..9aa3ab8 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -36,7 +36,7 @@ int xen_setup_shutdown_event(void);
extern unsigned long *xen_contiguous_bitmap;
int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
- dma_addr_t *dma_handle);
+ dma_addr_t *dma_handle, bool size_align);
void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order);
--
2.7.4
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^ permalink raw reply related [flat|nested] 6+ messages in thread