linux-kernel - [PATCH 1/1] drm/ttm: Set memory as decrypted for ttm framebuffer mappings

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Date:   Wed, 22 Aug 2018 13:57:54 -0500
From:   Jiandi An <jiandi.an@....com>
To:     dri-devel@...ts.freedesktop.org
Cc:     jiandi.an@....com, christian.koenig@....com, ray.huang@....com,
        Jerry.Zhang@....com, airlied@...ux.ie, linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] drm/ttm: Set memory as decrypted for ttm framebuffer mappings

Framebuffer memory needs to be accessed decrypted.  Ensure the
memory encryption mask is not set for the ttm framebuffer mappings.

Signed-off-by: Jiandi An <jiandi.an@....com>
---
 drivers/gpu/drm/ttm/ttm_bo_util.c | 12 +++++++++++-
 drivers/gpu/drm/ttm/ttm_bo_vm.c   |  6 ++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 046a6dda690a..b3f5d26f571e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -29,6 +29,7 @@
  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  */
 
+#include <asm/set_memory.h>
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
 #include <drm/drm_vma_manager.h>
@@ -639,7 +640,11 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
 	if (ret)
 		return ret;
 	if (!bo->mem.bus.is_iomem) {
-		return ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
+		ret = ttm_bo_kmap_ttm(bo, start_page, num_pages, map);
+		if (!ret && sev_active())
+			set_memory_decrypted((unsigned long) map->virtual,
+					     num_pages);
+		return ret;
 	} else {
 		offset = start_page << PAGE_SHIFT;
 		size = num_pages << PAGE_SHIFT;
@@ -661,9 +666,14 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
 		iounmap(map->virtual);
 		break;
 	case ttm_bo_map_vmap:
+		if (sev_active())
+			set_memory_encrypted((unsigned long) map->virtual,
+					     bo->num_pages);
 		vunmap(map->virtual);
 		break;
 	case ttm_bo_map_kmap:
+		if (sev_active())
+			set_memory_encrypted((unsigned long) map->virtual, 1);
 		kunmap(map->page);
 		break;
 	case ttm_bo_map_premapped:
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 6fe91c1b692d..211d3549fd9f 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -249,10 +249,12 @@ static vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
 	 * Speculatively prefault a number of pages. Only error on
 	 * first page.
 	 */
+
+	/* Mark framebuffer pages decrypted */
+	cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot);
+
 	for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
 		if (bo->mem.bus.is_iomem) {
-			/* Iomem should not be marked encrypted */
-			cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot);
 			pfn = ttm_bo_io_mem_pfn(bo, page_offset);
 		} else {
 			page = ttm->pages[page_offset];
-- 
2.17.1