Commit a636a0ff authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: Add a way for userspace to allocate GPU iova 



The motivation at this point is mainly native userspace mesa driver in a
VM guest.  The one remaining synchronous "hotpath" is buffer allocation,
because guest needs to wait to know the bo's iova before it can start
emitting cmdstream/state that references the new bo.  By allocating the
iova in the guest userspace, we no longer need to wait for a response
from the host, but can just rely on the allocation request being
processed before the cmdstream submission.  Allocation failures (OoM,
etc) would just be treated as context-lost (ie. GL_GUILTY_CONTEXT_RESET)
or subsequent allocations (or readpix, etc) can raise GL_OUT_OF_MEMORY.

v2: Fix inuse check
v3: Change mismatched iova case to -EBUSY

Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://lore.kernel.org/r/20220411215849.297838-11-robdclark@gmail.com


Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
parent 95d1deb0

drivers/gpu/drm/msm/adreno/adreno_gpu.c

+10 −0
Original line number Diff line number Diff line
@@ -281,6 +281,16 @@ int adreno_get_param(struct msm_gpu *gpu, struct msm_file_private *ctx, 
	case MSM_PARAM_SUSPENDS:

		*value = gpu->suspend_count;

		return 0;

	case MSM_PARAM_VA_START:

		if (ctx->aspace == gpu->aspace)

			return -EINVAL;

		*value = ctx->aspace->va_start;

		return 0;

	case MSM_PARAM_VA_SIZE:

		if (ctx->aspace == gpu->aspace)

			return -EINVAL;

		*value = ctx->aspace->va_size;

		return 0;

	default:

		DBG("%s: invalid param: %u", gpu->name, param);

		return -EINVAL;

drivers/gpu/drm/msm/msm_drv.c

+21 −0
Original line number Diff line number Diff line
@@ -722,6 +722,23 @@ static int msm_ioctl_gem_info_iova(struct drm_device *dev, 
	return msm_gem_get_iova(obj, ctx->aspace, iova);

}



static int msm_ioctl_gem_info_set_iova(struct drm_device *dev,

		struct drm_file *file, struct drm_gem_object *obj,

		uint64_t iova)

{

	struct msm_drm_private *priv = dev->dev_private;

	struct msm_file_private *ctx = file->driver_priv;



	if (!priv->gpu)

		return -EINVAL;



	/* Only supported if per-process address space is supported: */

	if (priv->gpu->aspace == ctx->aspace)

		return -EOPNOTSUPP;



	return msm_gem_set_iova(obj, ctx->aspace, iova);

}



static int msm_ioctl_gem_info(struct drm_device *dev, void *data,

		struct drm_file *file)

{
@@ -736,6 +753,7 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data, 
	switch (args->info) {

	case MSM_INFO_GET_OFFSET:

	case MSM_INFO_GET_IOVA:

	case MSM_INFO_SET_IOVA:

		/* value returned as immediate, not pointer, so len==0: */

		if (args->len)

			return -EINVAL;
@@ -760,6 +778,9 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data, 
	case MSM_INFO_GET_IOVA:

		ret = msm_ioctl_gem_info_iova(dev, file, obj, &args->value);

		break;

	case MSM_INFO_SET_IOVA:

		ret = msm_ioctl_gem_info_set_iova(dev, file, obj, args->value);

		break;

	case MSM_INFO_SET_NAME:

		/* length check should leave room for terminating null: */

		if (args->len >= sizeof(msm_obj->name)) {

drivers/gpu/drm/msm/msm_gem.c

+48 −0
Original line number Diff line number Diff line
@@ -525,6 +525,54 @@ int msm_gem_get_iova(struct drm_gem_object *obj, 
	return ret;

}



static int clear_iova(struct drm_gem_object *obj,

		      struct msm_gem_address_space *aspace)

{

	struct msm_gem_vma *vma = lookup_vma(obj, aspace);



	if (!vma)

		return 0;



	if (msm_gem_vma_inuse(vma))

		return -EBUSY;



	msm_gem_purge_vma(vma->aspace, vma);

	msm_gem_close_vma(vma->aspace, vma);

	del_vma(vma);



	return 0;

}



/*

 * Get the requested iova but don't pin it.  Fails if the requested iova is

 * not available.  Doesn't need a put because iovas are currently valid for

 * the life of the object.

 *

 * Setting an iova of zero will clear the vma.

 */

int msm_gem_set_iova(struct drm_gem_object *obj,

		     struct msm_gem_address_space *aspace, uint64_t iova)

{

	int ret = 0;



	msm_gem_lock(obj);

	if (!iova) {

		ret = clear_iova(obj, aspace);

	} else {

		struct msm_gem_vma *vma;

		vma = get_vma_locked(obj, aspace, iova, iova + obj->size);

		if (IS_ERR(vma)) {

			ret = PTR_ERR(vma);

		} else if (GEM_WARN_ON(vma->iova != iova)) {

			clear_iova(obj, aspace);

			ret = -EBUSY;

		}

	}

	msm_gem_unlock(obj);



	return ret;

}



/*

 * Unpin a iova by updating the reference counts. The memory isn't actually

 * purged until something else (shrinker, mm_notifier, destroy, etc) decides

drivers/gpu/drm/msm/msm_gem.h

+8 −0
Original line number Diff line number Diff line
@@ -38,6 +38,12 @@ struct msm_gem_address_space { 


	/* @faults: the number of GPU hangs associated with this address space */

	int faults;



	/** @va_start: lowest possible address to allocate */

	uint64_t va_start;



	/** @va_size: the size of the address space (in bytes) */

	uint64_t va_size;

};



struct msm_gem_address_space *
@@ -144,6 +150,8 @@ struct msm_gem_vma *msm_gem_get_vma_locked(struct drm_gem_object *obj, 
					   struct msm_gem_address_space *aspace);

int msm_gem_get_iova(struct drm_gem_object *obj,

		struct msm_gem_address_space *aspace, uint64_t *iova);

int msm_gem_set_iova(struct drm_gem_object *obj,

		struct msm_gem_address_space *aspace, uint64_t iova);

int msm_gem_get_and_pin_iova_range(struct drm_gem_object *obj,

		struct msm_gem_address_space *aspace, uint64_t *iova,

		u64 range_start, u64 range_end);

drivers/gpu/drm/msm/msm_gem_vma.c

+2 −0
Original line number Diff line number Diff line
@@ -184,6 +184,8 @@ msm_gem_address_space_create(struct msm_mmu *mmu, const char *name, 
	spin_lock_init(&aspace->lock);

	aspace->name = name;

	aspace->mmu = mmu;

	aspace->va_start = va_start;

	aspace->va_size  = size;



	drm_mm_init(&aspace->mm, va_start, size);