From 0b100760e3e8cbb2b5d09c1c2bcb01d50201c142 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 12 Jul 2018 20:14:30 +0100 Subject: [PATCH] drm/i915/userptr: Enable read-only support on gen8+ On gen8 and onwards, we can mark GPU accesses through the ppGTT as being read-only, that is cause any GPU write onto that page to be discarded (not triggering a fault). This is all that we need to finally support the read-only flag for userptr! v2: Check default address space for read only support as a proxy for the user context/ppgtt. Testcase: igt/gem_userptr_blits/readonly* Signed-off-by: Chris Wilson Cc: Jon Bloomfield Cc: Joonas Lahtinen Reviewed-by: Joonas Lahtinen Reviewed-by: Matthew Auld Reviewed-by: Jon Bloomfield Link: https://patchwork.freedesktop.org/patch/msgid/20180712191430.9269-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_object.h | 1 - drivers/gpu/drm/i915/i915_gem_userptr.c | 18 ++++++++++++------ 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_object.h b/drivers/gpu/drm/i915/i915_gem_object.h index 56e9f00..83e5e01 100644 --- a/drivers/gpu/drm/i915/i915_gem_object.h +++ b/drivers/gpu/drm/i915/i915_gem_object.h @@ -267,7 +267,6 @@ struct drm_i915_gem_object { union { struct i915_gem_userptr { uintptr_t ptr; - unsigned read_only :1; struct i915_mm_struct *mm; struct i915_mmu_object *mmu_object; diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 854bd51..dcd6e23 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -507,7 +507,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work) struct mm_struct *mm = obj->userptr.mm->mm; unsigned int flags = 0; - if (!obj->userptr.read_only) + if (!i915_gem_object_is_readonly(obj)) flags |= FOLL_WRITE; ret = -EFAULT; @@ -643,7 +643,7 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj) if (pvec) /* defer to worker if malloc fails */ pinned = __get_user_pages_fast(obj->userptr.ptr, num_pages, - !obj->userptr.read_only, + !i915_gem_object_is_readonly(obj), pvec); } @@ -789,10 +789,15 @@ i915_gem_userptr_ioctl(struct drm_device *dev, return -EFAULT; if (args->flags & I915_USERPTR_READ_ONLY) { - /* On almost all of the current hw, we cannot tell the GPU that a - * page is readonly, so this is just a placeholder in the uAPI. + struct i915_hw_ppgtt *ppgtt; + + /* + * On almost all of the older hw, we cannot tell the GPU that + * a page is readonly. */ - return -ENODEV; + ppgtt = dev_priv->kernel_context->ppgtt; + if (!ppgtt || !ppgtt->vm.has_read_only) + return -ENODEV; } obj = i915_gem_object_alloc(dev_priv); @@ -806,7 +811,8 @@ i915_gem_userptr_ioctl(struct drm_device *dev, i915_gem_object_set_cache_coherency(obj, I915_CACHE_LLC); obj->userptr.ptr = args->user_ptr; - obj->userptr.read_only = !!(args->flags & I915_USERPTR_READ_ONLY); + if (args->flags & I915_USERPTR_READ_ONLY) + i915_gem_object_set_readonly(obj); /* And keep a pointer to the current->mm for resolving the user pages * at binding. This means that we need to hook into the mmu_notifier -- 2.7.4