> -----Original Message----- > From: Michael D Labriola [mailto:michael.d.labriola@xxxxxxxxx] > Sent: 19 February 2019 23:08 > To: dri-devel@xxxxxxxxxxxxxxxxxxxxx; Alex Deucher > <alexander.deucher@xxxxxxx>; Christian Koenig <christian.koenig@xxxxxxx>; > Chunming Zhou <david1.zhou@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Monk > Liu <monk.liu@xxxxxxx> > Cc: Juergen Gross <jgross@xxxxxxxx>; Christoph Hellwig > <hch@xxxxxxxxxxxxx>; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Paul > Durrant <Paul.Durrant@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxx; Jan Beulich > <JBeulich@xxxxxxxx>; Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>; > Michael D Labriola <michael.d.labriola@xxxxxxxxx> > Subject: [PATCH] drm: add func to better detect wether swiotlb is needed > > 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 <michael.d.labriola@xxxxxxxxx> > --- > 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 910c4ce..6bc0266 100644 > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c > @@ -1029,7 +1029,7 @@ 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 747c068..8638adf 100644 > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c > @@ -1155,7 +1155,7 @@ 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 f35d7a5..4f67093 100644 > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c > @@ -989,7 +989,7 @@ 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); > > if (adev->asic_type == CHIP_VEGA20) { > r = gfxhub_v1_1_get_xgmi_info(adev); > diff --git a/drivers/gpu/drm/drm_memory.c b/drivers/gpu/drm/drm_memory.c > index d69e4fc..6af59a6 100644 > --- a/drivers/gpu/drm/drm_memory.c > +++ b/drivers/gpu/drm/drm_memory.c > @@ -35,6 +35,7 @@ > > #include <linux/highmem.h> > #include <linux/export.h> > +#include <xen/xen.h> > #include <drm/drmP.h> > #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()) I've not been following all of the ins and outs of the discussion on this so apologies if I'm missing some context, but... This looks like the wrong test to me. I think it should be: if ( xen_swiotlb ) > + return true; > + Paul > 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 59c8a66..a1d3c62 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 bfe1639..633eaaf 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) > -- > 1.8.3.1 _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
