From 4fcb87529a644016dc00459681efafc542e7c202 Mon Sep 17 00:00:00 2001 From: Michael D Labriola Date: Tue, 19 Feb 2019 18:08:12 -0500 Subject: [PATCH] drm: change func to better detect wether swiotlb is needed MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This commit fixes DRM failures on Xen PV systems that were introduced in v4.17 by the following commits: 82626363 drm: add func to get max iomem address v2 fd5fd480 drm/amdgpu: only enable swiotlb alloc when need v2 1bc3d3cc drm/radeon: only enable swiotlb path when need v2 The introduction of ->need_swiotlb to the ttm_dma_populate() conditionals in the radeon and amdgpu device drivers causes Gnome to immediately crash on Xen PV systems, returning the user to the login screen. The following kernel errors get logged: [ 28.554259] radeon_dp_aux_transfer_native: 200 callbacks suppressed [ 31.219821] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 31.220030] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 31.226109] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 31.226300] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 31.300734] gnome-shell[1935]: segfault at 88 ip 00007f39151cd904 sp 00007ffc97611ad8 error 4 in libmutter-cogl.so[7f3915178000+aa000] [ 31.300745] Code: 5f c3 0f 1f 40 00 48 8b 47 78 48 8b 40 40 ff e0 66 0f 1f 44 00 00 48 8b 47 78 48 8b 40 48 ff e0 66 0f 1f 44 00 00 48 8b 47 78 <48> 8b 80 88 00 00 00 ff e0 0f 1f 00 48 8b 47 78 48 8b 40 68 ff e0 [ 38.193302] radeon_dp_aux_transfer_native: 116 callbacks suppressed [ 40.009317] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 40.009488] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 40.015114] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes) [ 40.015297] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14) [ 40.028302] gnome-shell[2431]: segfault at 2dadf40 ip 0000000002dadf40 sp 00007ffcd24ea5f8 error 15 [ 40.028306] Code: 20 6e 31 00 00 00 00 00 00 00 00 37 e3 3d 2d 7f 00 00 80 f4 e6 3d 2d 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 c1 00 00 00 00 00 00 00 80 e1 d2 03 00 00 This commit renames drm_get_max_iomem() to drm_need_swiotlb(), adds a xen_pv_domain() check to it, and moves the bit shifting comparison that always follows its usage into the function (simplifying the drm driver code). Signed-off-by: Michael D Labriola Reviewed-by: Christian König Signed-off-by: Christian König Link: https://patchwork.freedesktop.org/patch/286987/ (cherry picked from commit 913b2cb727b7a47ccf8842d54c89f1b873c6deed) --- drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 2 +- drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 2 +- drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 2 +- drivers/gpu/drm/drm_memory.c | 19 ++++++++++++++++--- drivers/gpu/drm/radeon/radeon_device.c | 2 +- include/drm/drm_cache.h | 2 +- 6 files changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c index f8d8a3a73e42..cd5bb3e248dc 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c @@ -1024,7 +1024,7 @@ static int gmc_v7_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); pr_warn("amdgpu: No coherent DMA available\n"); } - adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits); + adev->need_swiotlb = drm_need_swiotlb(dma_bits); r = gmc_v7_0_init_microcode(adev); if (r) { diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c index 1a744f964b30..831f72b26d3b 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c @@ -1150,7 +1150,7 @@ static int gmc_v8_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); pr_warn("amdgpu: No coherent DMA available\n"); } - adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits); + adev->need_swiotlb = drm_need_swiotlb(dma_bits); r = gmc_v8_0_init_microcode(adev); if (r) { diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c index 72f8018fa2a8..9ec47e726d78 100644 --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c @@ -911,7 +911,7 @@ static int gmc_v9_0_sw_init(void *handle) pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32)); printk(KERN_WARNING "amdgpu: No coherent DMA available.\n"); } - adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits); + adev->need_swiotlb = drm_need_swiotlb(dma_bits); r = gmc_v9_0_mc_init(adev); if (r) diff --git a/drivers/gpu/drm/drm_memory.c b/drivers/gpu/drm/drm_memory.c index d69e4fc1ee77..6af59a61f9b0 100644 --- a/drivers/gpu/drm/drm_memory.c +++ b/drivers/gpu/drm/drm_memory.c @@ -35,6 +35,7 @@ #include #include +#include #include #include "drm_legacy.h" @@ -150,15 +151,27 @@ void drm_legacy_ioremapfree(struct drm_local_map *map, struct drm_device *dev) } EXPORT_SYMBOL(drm_legacy_ioremapfree); -u64 drm_get_max_iomem(void) +bool drm_need_swiotlb(int dma_bits) { struct resource *tmp; resource_size_t max_iomem = 0; + /* + * Xen paravirtual hosts require swiotlb regardless of requested dma + * transfer size. + * + * NOTE: Really, what it requires is use of the dma_alloc_coherent + * allocator used in ttm_dma_populate() instead of + * ttm_populate_and_map_pages(), which bounce buffers so much in + * Xen it leads to swiotlb buffer exhaustion. + */ + if (xen_pv_domain()) + return true; + for (tmp = iomem_resource.child; tmp; tmp = tmp->sibling) { max_iomem = max(max_iomem, tmp->end); } - return max_iomem; + return max_iomem > ((u64)1 << dma_bits); } -EXPORT_SYMBOL(drm_get_max_iomem); +EXPORT_SYMBOL(drm_need_swiotlb); diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c index 59c8a6647ff2..a1d3c628c352 100644 --- a/drivers/gpu/drm/radeon/radeon_device.c +++ b/drivers/gpu/drm/radeon/radeon_device.c @@ -1387,7 +1387,7 @@ int radeon_device_init(struct radeon_device *rdev, pci_set_consistent_dma_mask(rdev->pdev, DMA_BIT_MASK(32)); pr_warn("radeon: No coherent DMA available\n"); } - rdev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits); + rdev->need_swiotlb = drm_need_swiotlb(dma_bits); /* Registers mapping */ /* TODO: block userspace mapping of io register */ diff --git a/include/drm/drm_cache.h b/include/drm/drm_cache.h index 97fc498dc767..987ff16b9420 100644 --- a/include/drm/drm_cache.h +++ b/include/drm/drm_cache.h @@ -38,7 +38,7 @@ void drm_clflush_pages(struct page *pages[], unsigned long num_pages); void drm_clflush_sg(struct sg_table *st); void drm_clflush_virt_range(void *addr, unsigned long length); -u64 drm_get_max_iomem(void); +bool drm_need_swiotlb(int dma_bits); static inline bool drm_arch_can_wc_memory(void) -- 2.17.2