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-rw-r--r--lib/dma-direct.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index c9e8e21cb334..c0bba30fef0a 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -9,6 +9,7 @@
#include <linux/scatterlist.h>
#include <linux/dma-contiguous.h>
#include <linux/pfn.h>
+#include <linux/set_memory.h>
#define DIRECT_MAPPING_ERROR 0
@@ -20,6 +21,14 @@
#define ARCH_ZONE_DMA_BITS 24
#endif
+/*
+ * For AMD SEV all DMA must be to unencrypted addresses.
+ */
+static inline bool force_dma_unencrypted(void)
+{
+ return sev_active();
+}
+
static bool
check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,
const char *caller)
@@ -37,7 +46,9 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,
static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
- return phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
+ dma_addr_t addr = force_dma_unencrypted() ?
+ __phys_to_dma(dev, phys) : phys_to_dma(dev, phys);
+ return addr + size - 1 <= dev->coherent_dma_mask;
}
void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
@@ -46,6 +57,10 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size);
struct page *page = NULL;
+ void *ret;
+
+ /* we always manually zero the memory once we are done: */
+ gfp &= ~__GFP_ZERO;
/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
@@ -78,10 +93,15 @@ again:
if (!page)
return NULL;
-
- *dma_handle = phys_to_dma(dev, page_to_phys(page));
- memset(page_address(page), 0, size);
- return page_address(page);
+ ret = page_address(page);
+ if (force_dma_unencrypted()) {
+ set_memory_decrypted((unsigned long)ret, 1 << page_order);
+ *dma_handle = __phys_to_dma(dev, page_to_phys(page));
+ } else {
+ *dma_handle = phys_to_dma(dev, page_to_phys(page));
+ }
+ memset(ret, 0, size);
+ return ret;
}
/*
@@ -92,9 +112,12 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ unsigned int page_order = get_order(size);
+ if (force_dma_unencrypted())
+ set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
- free_pages((unsigned long)cpu_addr, get_order(size));
+ free_pages((unsigned long)cpu_addr, page_order);
}
static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,