From: Rob Clark <robdcl...@chromium.org>

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: Rob Clark <robdcl...@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.barysh...@linaro.org>
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 10 ++++++
 drivers/gpu/drm/msm/msm_drv.c           | 21 +++++++++++
 drivers/gpu/drm/msm/msm_gem.c           | 48 +++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_gem.h           |  8 +++++
 drivers/gpu/drm/msm/msm_gem_vma.c       |  2 ++
 include/uapi/drm/msm_drm.h              |  3 ++
 6 files changed, 92 insertions(+)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c 
b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 6385ab06632f..4caae0229518 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -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;
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index d618953d33ea..34e2169308b4 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -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)) {
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index bf4af17e2f1e..3ee30b8a76bd 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -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
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index 38d66e1248b1..efa2e5c19f1e 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -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);
diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c 
b/drivers/gpu/drm/msm/msm_gem_vma.c
index 6f9a402450f9..354f91aff573 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -182,6 +182,8 @@ 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);
 
diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index 794ad1948497..3c7b097c4e3d 100644
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -84,6 +84,8 @@ struct drm_msm_timespec {
 #define MSM_PARAM_SYSPROF    0x0b  /* WO: 1 preserves perfcntrs, 2 also 
disables suspend */
 #define MSM_PARAM_COMM       0x0c  /* WO: override for task->comm */
 #define MSM_PARAM_CMDLINE    0x0d  /* WO: override for task cmdline */
+#define MSM_PARAM_VA_START   0x0e  /* RO: start of valid GPU iova range */
+#define MSM_PARAM_VA_SIZE    0x0f  /* RO: size of valid GPU iova range (bytes) 
*/
 
 /* For backwards compat.  The original support for preemption was based on
  * a single ring per priority level so # of priority levels equals the #
@@ -135,6 +137,7 @@ struct drm_msm_gem_new {
 #define MSM_INFO_GET_IOVA      0x01   /* get iova, returned by value */
 #define MSM_INFO_SET_NAME      0x02   /* set the debug name (by pointer) */
 #define MSM_INFO_GET_NAME      0x03   /* get debug name, returned by pointer */
+#define MSM_INFO_SET_IOVA      0x04   /* set the iova, passed by value */
 
 struct drm_msm_gem_info {
        __u32 handle;         /* in */
-- 
2.35.1

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