From 95cf9264d5f36c291c1c50c00349f83348e6f9c7 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Mon, 17 Jul 2017 16:10:26 -0500 Subject: [PATCH] x86, drm, fbdev: Do not specify encrypted memory for video mappings MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Since video memory needs to be accessed decrypted, be sure that the memory encryption mask is not set for the video ranges. Signed-off-by: Tom Lendacky Reviewed-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Dmitry Vyukov Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Larry Woodman Cc: Linus Torvalds Cc: Matt Fleming Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Toshimitsu Kani Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/a19436f30424402e01f63a09b32ab103272acced.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/vga.h | 14 +++++++++++++- arch/x86/mm/pageattr.c | 2 ++ 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 ++++++++++++ 7 files changed, 42 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/vga.h b/arch/x86/include/asm/vga.h index c4b9dc2f67c5..9f42beefc67a 100644 --- a/arch/x86/include/asm/vga.h +++ b/arch/x86/include/asm/vga.h @@ -7,12 +7,24 @@ #ifndef _ASM_X86_VGA_H #define _ASM_X86_VGA_H +#include + /* * 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 decrypted memory. */ -#define VGA_MAP_MEM(x, s) (unsigned long)phys_to_virt(x) +#define VGA_MAP_MEM(x, s) \ +({ \ + unsigned long start = (unsigned long)phys_to_virt(x); \ + \ + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) \ + set_memory_decrypted(start, (s) >> PAGE_SHIFT); \ + \ + start; \ +}) #define vga_readb(x) (*(x)) #define vga_writeb(x, y) (*(y) = (x)) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 9c8ea129ff5c..dfb7d657cf43 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1831,11 +1831,13 @@ int set_memory_encrypted(unsigned long addr, int numpages) { return __set_memory_enc_dec(addr, numpages, true); } +EXPORT_SYMBOL_GPL(set_memory_encrypted); int set_memory_decrypted(unsigned long addr, int numpages) { return __set_memory_enc_dec(addr, numpages, false); } +EXPORT_SYMBOL_GPL(set_memory_decrypted); int set_pages_uc(struct page *page, int numpages) { diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 8dc11064253d..7a61a07ac4de 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include #include @@ -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)); + vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); /* 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 1170b3209a12..ed4bcbfd6086 100644 --- a/drivers/gpu/drm/drm_vm.c +++ b/drivers/gpu/drm/drm_vm.c @@ -40,6 +40,7 @@ #include #include #endif +#include #include #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 */ + tmp = pgprot_decrypted(tmp); + #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 b442d12f2f7d..84fb009d4eb0 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -39,6 +39,7 @@ #include #include #include +#include #define TTM_BO_VM_NUM_PREFAULT 16 @@ -230,9 +231,11 @@ static int ttm_bo_vm_fault(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 */ + cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot); pfn = bdev->driver->io_mem_pfn(bo, 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 4a6500362564..92e1690e28de 100644 --- a/drivers/gpu/drm/udl/udl_fb.c +++ b/drivers/gpu/drm/udl/udl_fb.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -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 */ + vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); + 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 7a42238db446..25e862c487f6 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -32,6 +32,7 @@ #include #include #include +#include #include @@ -1396,6 +1397,12 @@ 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 decrypted, be sure + * SME protection is removed ahead of the call + */ + vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); res = fb->fb_mmap(info, vma); mutex_unlock(&info->mm_lock); return res; @@ -1421,6 +1428,11 @@ 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 decrypted, be sure + * SME protection is removed + */ + vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot); fb_pgprotect(file, vma, start); return vm_iomap_memory(vma, start, len); -- 2.20.1