From 8ef4227615e158faa4ee85a1d6466782f7e22f2f Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Mon, 24 Oct 2016 15:27:59 +1000 Subject: [PATCH 1/2] x86/io: add interface to reserve io memtype for a resource range. (v1.1) A recent change to the mm code in: 87744ab3832b mm: fix cache mode tracking in vm_insert_mixed() started enforcing checking the memory type against the registered list for amixed pfn insertion mappings. It happens that the drm drivers for a number of gpus relied on this being broken. Currently the driver only inserted VRAM mappings into the tracking table when they came from the kernel, and userspace mappings never landed in the table. This led to a regression where all the mapping end up as UC instead of WC now. I've considered a number of solutions but since this needs to be fixed in fixes and not next, and some of the solutions were going to introduce overhead that hadn't been there before I didn't consider them viable at this stage. These mainly concerned hooking into the TTM io reserve APIs, but these API have a bunch of fast paths I didn't want to unwind to add this to. The solution I've decided on is to add a new API like the arch_phys_wc APIs (these would have worked but wc_del didn't take a range), and use them from the drivers to add a WC compatible mapping to the table for all VRAM on those GPUs. This means we can then create userspace mapping that won't get degraded to UC. v1.1: use CONFIG_X86_PAT + add some comments in io.h Cc: Toshi Kani Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Andy Lutomirski Cc: Denys Vlasenko Cc: Brian Gerst Cc: x86@kernel.org Cc: mcgrof@suse.com Cc: Dan Williams Acked-by: Ingo Molnar Reviewed-by: Thomas Gleixner Signed-off-by: Dave Airlie --- arch/x86/include/asm/io.h | 6 ++++++ arch/x86/mm/pat.c | 14 ++++++++++++++ include/linux/io.h | 22 ++++++++++++++++++++++ 3 files changed, 42 insertions(+) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index de25aad07853..d34bd370074b 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -351,4 +351,10 @@ extern void arch_phys_wc_del(int handle); #define arch_phys_wc_add arch_phys_wc_add #endif +#ifdef CONFIG_X86_PAT +extern int arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size); +extern void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size); +#define arch_io_reserve_memtype_wc arch_io_reserve_memtype_wc +#endif + #endif /* _ASM_X86_IO_H */ diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 170cc4ff057b..83e701f160a9 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -730,6 +730,20 @@ void io_free_memtype(resource_size_t start, resource_size_t end) free_memtype(start, end); } +int arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size) +{ + enum page_cache_mode type = _PAGE_CACHE_MODE_WC; + + return io_reserve_memtype(start, start + size, &type); +} +EXPORT_SYMBOL(arch_io_reserve_memtype_wc); + +void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size) +{ + io_free_memtype(start, start + size); +} +EXPORT_SYMBOL(arch_io_free_memtype_wc); + pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { diff --git a/include/linux/io.h b/include/linux/io.h index e2c8419278c1..82ef36eac8a1 100644 --- a/include/linux/io.h +++ b/include/linux/io.h @@ -141,4 +141,26 @@ enum { void *memremap(resource_size_t offset, size_t size, unsigned long flags); void memunmap(void *addr); +/* + * On x86 PAT systems we have memory tracking that keeps track of + * the allowed mappings on memory ranges. This tracking works for + * all the in-kernel mapping APIs (ioremap*), but where the user + * wishes to map a range from a physical device into user memory + * the tracking won't be updated. This API is to be used by + * drivers which remap physical device pages into userspace, + * and wants to make sure they are mapped WC and not UC. + */ +#ifndef arch_io_reserve_memtype_wc +static inline int arch_io_reserve_memtype_wc(resource_size_t base, + resource_size_t size) +{ + return 0; +} + +static inline void arch_io_free_memtype_wc(resource_size_t base, + resource_size_t size) +{ +} +#endif + #endif /* _LINUX_IO_H */ From 7cf321d118a825c1541b43ca45294126fd474efa Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Mon, 24 Oct 2016 15:37:48 +1000 Subject: [PATCH 2/2] drm/drivers: add support for using the arch wc mapping API. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This fixes a regression in all these drivers since the cache mode tracking was fixed for mixed mappings. It uses the new arch API to add the VRAM range to the PAT mapping tracking tables. Fixes: 87744ab3832 (mm: fix cache mode tracking in vm_insert_mixed()) Reviewed-by: Christian König . Signed-off-by: Dave Airlie --- drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 5 +++++ drivers/gpu/drm/ast/ast_ttm.c | 6 ++++++ drivers/gpu/drm/cirrus/cirrus_ttm.c | 7 +++++++ drivers/gpu/drm/mgag200/mgag200_ttm.c | 7 +++++++ drivers/gpu/drm/nouveau/nouveau_ttm.c | 8 ++++++++ drivers/gpu/drm/radeon/radeon_object.c | 5 +++++ 6 files changed, 38 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c index aa074fac0c7f..f3efb1c5dae9 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c @@ -754,6 +754,10 @@ static const char *amdgpu_vram_names[] = { int amdgpu_bo_init(struct amdgpu_device *adev) { + /* reserve PAT memory space to WC for VRAM */ + arch_io_reserve_memtype_wc(adev->mc.aper_base, + adev->mc.aper_size); + /* Add an MTRR for the VRAM */ adev->mc.vram_mtrr = arch_phys_wc_add(adev->mc.aper_base, adev->mc.aper_size); @@ -769,6 +773,7 @@ void amdgpu_bo_fini(struct amdgpu_device *adev) { amdgpu_ttm_fini(adev); arch_phys_wc_del(adev->mc.vram_mtrr); + arch_io_free_memtype_wc(adev->mc.aper_base, adev->mc.aper_size); } int amdgpu_bo_fbdev_mmap(struct amdgpu_bo *bo, diff --git a/drivers/gpu/drm/ast/ast_ttm.c b/drivers/gpu/drm/ast/ast_ttm.c index 608df4c90520..0743e65cb240 100644 --- a/drivers/gpu/drm/ast/ast_ttm.c +++ b/drivers/gpu/drm/ast/ast_ttm.c @@ -267,6 +267,8 @@ int ast_mm_init(struct ast_private *ast) return ret; } + arch_io_reserve_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); ast->fb_mtrr = arch_phys_wc_add(pci_resource_start(dev->pdev, 0), pci_resource_len(dev->pdev, 0)); @@ -275,11 +277,15 @@ int ast_mm_init(struct ast_private *ast) void ast_mm_fini(struct ast_private *ast) { + struct drm_device *dev = ast->dev; + ttm_bo_device_release(&ast->ttm.bdev); ast_ttm_global_release(ast); arch_phys_wc_del(ast->fb_mtrr); + arch_io_free_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); } void ast_ttm_placement(struct ast_bo *bo, int domain) diff --git a/drivers/gpu/drm/cirrus/cirrus_ttm.c b/drivers/gpu/drm/cirrus/cirrus_ttm.c index bb2438dd8733..5e7e63ce7bce 100644 --- a/drivers/gpu/drm/cirrus/cirrus_ttm.c +++ b/drivers/gpu/drm/cirrus/cirrus_ttm.c @@ -267,6 +267,9 @@ int cirrus_mm_init(struct cirrus_device *cirrus) return ret; } + arch_io_reserve_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); + cirrus->fb_mtrr = arch_phys_wc_add(pci_resource_start(dev->pdev, 0), pci_resource_len(dev->pdev, 0)); @@ -276,6 +279,8 @@ int cirrus_mm_init(struct cirrus_device *cirrus) void cirrus_mm_fini(struct cirrus_device *cirrus) { + struct drm_device *dev = cirrus->dev; + if (!cirrus->mm_inited) return; @@ -285,6 +290,8 @@ void cirrus_mm_fini(struct cirrus_device *cirrus) arch_phys_wc_del(cirrus->fb_mtrr); cirrus->fb_mtrr = 0; + arch_io_free_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); } void cirrus_ttm_placement(struct cirrus_bo *bo, int domain) diff --git a/drivers/gpu/drm/mgag200/mgag200_ttm.c b/drivers/gpu/drm/mgag200/mgag200_ttm.c index 919b35f2ad24..dcf7d11ac380 100644 --- a/drivers/gpu/drm/mgag200/mgag200_ttm.c +++ b/drivers/gpu/drm/mgag200/mgag200_ttm.c @@ -266,6 +266,9 @@ int mgag200_mm_init(struct mga_device *mdev) return ret; } + arch_io_reserve_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); + mdev->fb_mtrr = arch_phys_wc_add(pci_resource_start(dev->pdev, 0), pci_resource_len(dev->pdev, 0)); @@ -274,10 +277,14 @@ int mgag200_mm_init(struct mga_device *mdev) void mgag200_mm_fini(struct mga_device *mdev) { + struct drm_device *dev = mdev->dev; + ttm_bo_device_release(&mdev->ttm.bdev); mgag200_ttm_global_release(mdev); + arch_io_free_memtype_wc(pci_resource_start(dev->pdev, 0), + pci_resource_len(dev->pdev, 0)); arch_phys_wc_del(mdev->fb_mtrr); mdev->fb_mtrr = 0; } diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c b/drivers/gpu/drm/nouveau/nouveau_ttm.c index 1825dbc33192..a6dbe8258040 100644 --- a/drivers/gpu/drm/nouveau/nouveau_ttm.c +++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c @@ -398,6 +398,9 @@ nouveau_ttm_init(struct nouveau_drm *drm) /* VRAM init */ drm->gem.vram_available = drm->device.info.ram_user; + arch_io_reserve_memtype_wc(device->func->resource_addr(device, 1), + device->func->resource_size(device, 1)); + ret = ttm_bo_init_mm(&drm->ttm.bdev, TTM_PL_VRAM, drm->gem.vram_available >> PAGE_SHIFT); if (ret) { @@ -430,6 +433,8 @@ nouveau_ttm_init(struct nouveau_drm *drm) void nouveau_ttm_fini(struct nouveau_drm *drm) { + struct nvkm_device *device = nvxx_device(&drm->device); + ttm_bo_clean_mm(&drm->ttm.bdev, TTM_PL_VRAM); ttm_bo_clean_mm(&drm->ttm.bdev, TTM_PL_TT); @@ -439,4 +444,7 @@ nouveau_ttm_fini(struct nouveau_drm *drm) arch_phys_wc_del(drm->ttm.mtrr); drm->ttm.mtrr = 0; + arch_io_free_memtype_wc(device->func->resource_addr(device, 1), + device->func->resource_size(device, 1)); + } diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c index be30861afae9..41b72ce6613f 100644 --- a/drivers/gpu/drm/radeon/radeon_object.c +++ b/drivers/gpu/drm/radeon/radeon_object.c @@ -446,6 +446,10 @@ void radeon_bo_force_delete(struct radeon_device *rdev) int radeon_bo_init(struct radeon_device *rdev) { + /* reserve PAT memory space to WC for VRAM */ + arch_io_reserve_memtype_wc(rdev->mc.aper_base, + rdev->mc.aper_size); + /* Add an MTRR for the VRAM */ if (!rdev->fastfb_working) { rdev->mc.vram_mtrr = arch_phys_wc_add(rdev->mc.aper_base, @@ -463,6 +467,7 @@ void radeon_bo_fini(struct radeon_device *rdev) { radeon_ttm_fini(rdev); arch_phys_wc_del(rdev->mc.vram_mtrr); + arch_io_free_memtype_wc(rdev->mc.aper_base, rdev->mc.aper_size); } /* Returns how many bytes TTM can move per IB.