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Date: Wed, 9 Nov 2016 18:37:53 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: <linux-arch@...r.kernel.org>, <linux-efi@...r.kernel.org>,
<kvm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<x86@...nel.org>, <linux-kernel@...r.kernel.org>,
<kasan-dev@...glegroups.com>, <linux-mm@...ck.org>,
<iommu@...ts.linux-foundation.org>
CC: Rik van Riel <riel@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
Jonathan Corbet <corbet@....net>,
Matt Fleming <matt@...eblueprint.co.uk>,
Joerg Roedel <joro@...tes.org>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
"Paolo Bonzini" <pbonzini@...hat.com>,
Larry Woodman <lwoodman@...hat.com>,
"Ingo Molnar" <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Andy Lutomirski <luto@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Alexander Potapenko <glider@...gle.com>,
"Thomas Gleixner" <tglx@...utronix.de>,
Dmitry Vyukov <dvyukov@...gle.com>
Subject: [RFC PATCH v3 16/20] x86: Do not specify encrypted memory for video
mappings
Since video memory needs to be accessed unencrypted be sure that the
memory encryption mask is not set for the video ranges.
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
arch/x86/include/asm/vga.h | 13 +++++++++++++
drivers/gpu/drm/drm_gem.c | 2 ++
drivers/gpu/drm/drm_vm.c | 4 ++++
drivers/gpu/drm/ttm/ttm_bo_vm.c | 7 +++++--
drivers/gpu/drm/udl/udl_fb.c | 4 ++++
drivers/video/fbdev/core/fbmem.c | 12 ++++++++++++
6 files changed, 40 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/vga.h b/arch/x86/include/asm/vga.h
index c4b9dc2..7f944a4 100644
--- a/arch/x86/include/asm/vga.h
+++ b/arch/x86/include/asm/vga.h
@@ -7,12 +7,25 @@
#ifndef _ASM_X86_VGA_H
#define _ASM_X86_VGA_H
+#include <asm/mem_encrypt.h>
+
/*
* On the PC, we can just recalculate addresses and then
* access the videoram directly without any black magic.
+ * To support memory encryption however, we need to access
+ * the videoram as un-encrypted memory.
*/
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+#define VGA_MAP_MEM(x, s) \
+({ \
+ unsigned long start = (unsigned long)phys_to_virt(x); \
+ sme_set_mem_unenc((void *)start, s); \
+ start; \
+})
+#else
#define VGA_MAP_MEM(x, s) (unsigned long)phys_to_virt(x)
+#endif
#define vga_readb(x) (*(x))
#define vga_writeb(x, y) (*(y) = (x))
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 9134ae1..44f9563 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -36,6 +36,7 @@
#include <linux/pagemap.h>
#include <linux/shmem_fs.h>
#include <linux/dma-buf.h>
+#include <linux/mem_encrypt.h>
#include <drm/drmP.h>
#include <drm/drm_vma_manager.h>
#include <drm/drm_gem.h>
@@ -928,6 +929,7 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
vma->vm_ops = dev->driver->gem_vm_ops;
vma->vm_private_data = obj;
vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+ pgprot_val(vma->vm_page_prot) &= ~sme_me_mask;
/* Take a ref for this mapping of the object, so that the fault
* handler can dereference the mmap offset's pointer to the object.
diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
index caa4e4c..d04752c 100644
--- a/drivers/gpu/drm/drm_vm.c
+++ b/drivers/gpu/drm/drm_vm.c
@@ -40,6 +40,7 @@
#include <linux/efi.h>
#include <linux/slab.h>
#endif
+#include <linux/mem_encrypt.h>
#include <asm/pgtable.h>
#include "drm_internal.h"
#include "drm_legacy.h"
@@ -58,6 +59,9 @@ static pgprot_t drm_io_prot(struct drm_local_map *map,
{
pgprot_t tmp = vm_get_page_prot(vma->vm_flags);
+ /* We don't want graphics memory to be mapped encrypted */
+ pgprot_val(tmp) &= ~sme_me_mask;
+
#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
if (map->type == _DRM_REGISTERS && !(map->flags & _DRM_WRITE_COMBINING))
tmp = pgprot_noncached(tmp);
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index a6ed9d5..f5fbd53 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -39,6 +39,7 @@
#include <linux/rbtree.h>
#include <linux/module.h>
#include <linux/uaccess.h>
+#include <linux/mem_encrypt.h>
#define TTM_BO_VM_NUM_PREFAULT 16
@@ -218,9 +219,11 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
* first page.
*/
for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
- if (bo->mem.bus.is_iomem)
+ if (bo->mem.bus.is_iomem) {
+ /* Iomem should not be marked encrypted */
+ pgprot_val(cvma.vm_page_prot) &= ~sme_me_mask;
pfn = ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT) + page_offset;
- else {
+ } else {
page = ttm->pages[page_offset];
if (unlikely(!page && i == 0)) {
retval = VM_FAULT_OOM;
diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
index 611b6b9..64212ca 100644
--- a/drivers/gpu/drm/udl/udl_fb.c
+++ b/drivers/gpu/drm/udl/udl_fb.c
@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/dma-buf.h>
+#include <linux/mem_encrypt.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
@@ -169,6 +170,9 @@ static int udl_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
pos, size);
+ /* We don't want the framebuffer to be mapped encrypted */
+ pgprot_val(vma->vm_page_prot) &= ~sme_me_mask;
+
while (size > 0) {
page = vmalloc_to_pfn((void *)pos);
if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 76c1ad9..ac51a5e 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -32,6 +32,7 @@
#include <linux/device.h>
#include <linux/efi.h>
#include <linux/fb.h>
+#include <linux/mem_encrypt.h>
#include <asm/fb.h>
@@ -1405,6 +1406,12 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
mutex_lock(&info->mm_lock);
if (fb->fb_mmap) {
int res;
+
+ /*
+ * The framebuffer needs to be accessed un-encrypted, be sure
+ * SME protection is removed ahead of the call
+ */
+ pgprot_val(vma->vm_page_prot) &= ~sme_me_mask;
res = fb->fb_mmap(info, vma);
mutex_unlock(&info->mm_lock);
return res;
@@ -1430,6 +1437,11 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
mutex_unlock(&info->mm_lock);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+ /*
+ * The framebuffer needs to be accessed un-encrypted, be sure
+ * SME protection is removed
+ */
+ pgprot_val(vma->vm_page_prot) &= ~sme_me_mask;
fb_pgprotect(file, vma, start);
return vm_iomap_memory(vma, start, len);
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