1 files changed, 26 insertions, 6 deletions

diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index c9e8e21cb334..1277d293d4da 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 +57,7 @@ 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;
 
         /* 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 +90,15 @@ 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 +109,12 @@ 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,