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Subject[PATCH 2/2] xen/arm: introduce XENMEM_cache_flush
Date
Introduce support for new hypercall XENMEM_cache_flush.
Use it to perform cache flashing on pages used for dma when necessary.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
arch/arm/xen/mm32.c | 19 ++++++++++++++++++-
include/xen/interface/memory.h | 16 ++++++++++++++++
2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/arm/xen/mm32.c b/arch/arm/xen/mm32.c
index a5a93fc..aa45332 100644
--- a/arch/arm/xen/mm32.c
+++ b/arch/arm/xen/mm32.c
@@ -4,6 +4,9 @@
#include <linux/highmem.h>

#include <xen/features.h>
+#include <xen/interface/memory.h>
+
+#include <asm/xen/hypercall.h>


/* functions called by SWIOTLB */
@@ -24,7 +27,21 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset,

if (!pfn_valid(pfn))
{
- /* TODO: cache flush */
+ struct xen_cache_flush cflush;
+
+ cflush.op = 0;
+ cflush.addr = handle + offset;
+ cflush.size = size;
+
+ if (op == dmac_unmap_area && dir != DMA_TO_DEVICE)
+ cflush.op = XENMEM_CACHE_INVAL;
+ if (op == dmac_map_area) {
+ cflush.op = XENMEM_CACHE_CLEAN;
+ if (dir == DMA_FROM_DEVICE)
+ cflush.op |= XENMEM_CACHE_INVAL;
+ }
+ if (cflush.op)
+ HYPERVISOR_memory_op(XENMEM_cache_flush, &cflush);
} else {
struct page *page = pfn_to_page(pfn);

diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index 2ecfe4f..7d7e039 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -263,4 +263,20 @@ struct xen_remove_from_physmap {
};
DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);

+/*
+ * Issue one or more cache maintenance operations on a memory range
+ * owned by the calling domain or granted to the calling domain by a
+ * foreign domain.
+ */
+#define XENMEM_cache_flush 27
+struct xen_cache_flush {
+/* addr is the machine address at the start of the memory range */
+uint64_t addr;
+uint64_t size;
+#define XENMEM_CACHE_CLEAN (1<<0)
+#define XENMEM_CACHE_INVAL (1<<1)
+uint32_t op;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_cache_flush);
+
#endif /* __XEN_PUBLIC_MEMORY_H__ */
--
1.7.10.4


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