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Message-ID: <20241207161651.410556-15-robdclark@gmail.com>
Date: Sat, 7 Dec 2024 08:15:14 -0800
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: freedreno@...ts.freedesktop.org,
linux-arm-msm@...r.kernel.org,
Connor Abbott <cwabbott0@...il.com>,
Akhil P Oommen <quic_akhilpo@...cinc.com>,
Rob Clark <robdclark@...omium.org>,
Rob Clark <robdclark@...il.com>,
Sean Paul <sean@...rly.run>,
Konrad Dybcio <konradybcio@...nel.org>,
Abhinav Kumar <quic_abhinavk@...cinc.com>,
Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
Marijn Suijten <marijn.suijten@...ainline.org>,
David Airlie <airlied@...il.com>,
Simona Vetter <simona@...ll.ch>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
linux-kernel@...r.kernel.org (open list)
Subject: [RFC 14/24] drm/msm: Add opt-in for VM_BIND
From: Rob Clark <robdclark@...omium.org>
Add a SET_PARAM for userspace to request to manage to the VM itself,
instead of getting a kernel managed VM.
In order to transition to a userspace managed VM, this param must be set
before any mappings are created.
Signed-off-by: Rob Clark <robdclark@...omium.org>
---
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++--
drivers/gpu/drm/msm/adreno/adreno_gpu.c | 15 +++++++++++++
drivers/gpu/drm/msm/msm_drv.c | 13 +++++++++--
drivers/gpu/drm/msm/msm_gem.c | 5 +++++
drivers/gpu/drm/msm/msm_gpu.c | 5 +++--
drivers/gpu/drm/msm/msm_gpu.h | 29 +++++++++++++++++++++++--
include/uapi/drm/msm_drm.h | 24 ++++++++++++++++++++
7 files changed, 87 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 97ec1dedeb98..ced5206bdc81 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -2251,7 +2251,7 @@ a6xx_create_vm(struct msm_gpu *gpu, struct platform_device *pdev)
}
static struct drm_gpuvm *
-a6xx_create_private_vm(struct msm_gpu *gpu)
+a6xx_create_private_vm(struct msm_gpu *gpu, bool kernel_managed)
{
struct msm_mmu *mmu;
@@ -2261,7 +2261,7 @@ a6xx_create_private_vm(struct msm_gpu *gpu)
return ERR_CAST(mmu);
return msm_gem_vm_create(gpu->dev, mmu, "gpu", 0x100000000ULL,
- adreno_private_vm_size(gpu), true);
+ adreno_private_vm_size(gpu), kernel_managed);
}
static uint32_t a6xx_get_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 033c1c9c457e..90848852ee50 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -444,6 +444,21 @@ int adreno_set_param(struct msm_gpu *gpu, struct msm_context *ctx,
if (!capable(CAP_SYS_ADMIN))
return UERR(EPERM, drm, "invalid permissions");
return msm_context_set_sysprof(ctx, gpu, value);
+ case MSM_PARAM_EN_VM_BIND:
+ /* We can only support VM_BIND with per-process pgtables: */
+ if (ctx->vm == gpu->vm)
+ return UERR(EINVAL, drm, "requires per-process pgtables");
+
+ /*
+ * We can only swtich to VM_BIND mode if the VM has not yet
+ * been created:
+ */
+ if (ctx->vm)
+ return UERR(EBUSY, drm, "VM already created");
+
+ ctx->userspace_managed_vm = value;
+
+ return 0;
default:
return UERR(EINVAL, drm, "%s: invalid param: %u", gpu->name, param);
}
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 7a23549db97d..b31ec287c600 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -229,8 +229,11 @@ static void load_gpu(struct drm_device *dev)
struct drm_gpuvm *msm_context_vm(struct drm_device *dev, struct msm_context *ctx)
{
struct msm_drm_private *priv = dev->dev_private;
- if (!ctx->vm)
- ctx->vm = msm_gpu_create_private_vm(priv->gpu, current);
+ if (!ctx->vm) {
+ ctx->vm = msm_gpu_create_private_vm(
+ priv->gpu, current, !ctx->userspace_managed_vm);
+
+ }
return ctx->vm;
}
@@ -419,6 +422,9 @@ static int msm_ioctl_gem_info_iova(struct drm_device *dev,
if (!priv->gpu)
return -EINVAL;
+ if (msm_context_is_vmbind(ctx))
+ return UERR(EINVAL, dev, "VM_BIND is enabled");
+
if (should_fail(&fail_gem_iova, obj->size))
return -ENOMEM;
@@ -440,6 +446,9 @@ static int msm_ioctl_gem_info_set_iova(struct drm_device *dev,
if (!priv->gpu)
return -EINVAL;
+ if (msm_context_is_vmbind(ctx))
+ return UERR(EINVAL, dev, "VM_BIND is enabled");
+
/* Only supported if per-process address space is supported: */
if (priv->gpu->vm == vm)
return UERR(EOPNOTSUPP, dev, "requires per-process pgtables");
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 99e0ce38cd92..0bfc993571fc 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -47,8 +47,13 @@ static void put_iova_spaces(struct drm_gem_object *obj, bool close);
static void msm_gem_close(struct drm_gem_object *obj, struct drm_file *file)
{
+ struct msm_context *ctx = file->driver_priv;
+
update_ctx_mem(file, -obj->size);
+ if (msm_context_is_vmbind(ctx))
+ return;
+
/*
* TODO we might need to kick this to a queue to avoid blocking
* in CLOSE ioctl
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 17d8be47db19..5def12abac6c 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -822,7 +822,8 @@ static int get_clocks(struct platform_device *pdev, struct msm_gpu *gpu)
/* Return a new address space for a msm_drm_private instance */
struct drm_gpuvm *
-msm_gpu_create_private_vm(struct msm_gpu *gpu, struct task_struct *task)
+msm_gpu_create_private_vm(struct msm_gpu *gpu, struct task_struct *task,
+ bool kernel_managed)
{
struct drm_gpuvm *vm = NULL;
@@ -834,7 +835,7 @@ msm_gpu_create_private_vm(struct msm_gpu *gpu, struct task_struct *task)
* the global one
*/
if (gpu->funcs->create_private_vm) {
- vm = gpu->funcs->create_private_vm(gpu);
+ vm = gpu->funcs->create_private_vm(gpu, kernel_managed);
if (!IS_ERR(vm))
to_msm_vm(vm)->pid = get_pid(task_pid(task));
}
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 5efbca0b9fb1..70abbd93e11b 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -79,7 +79,7 @@ struct msm_gpu_funcs {
void (*gpu_set_freq)(struct msm_gpu *gpu, struct dev_pm_opp *opp,
bool suspended);
struct drm_gpuvm *(*create_vm)(struct msm_gpu *gpu, struct platform_device *pdev);
- struct drm_gpuvm *(*create_private_vm)(struct msm_gpu *gpu);
+ struct drm_gpuvm *(*create_private_vm)(struct msm_gpu *gpu, bool kernel_managed);
uint32_t (*get_rptr)(struct msm_gpu *gpu, struct msm_ringbuffer *ring);
/**
@@ -354,6 +354,14 @@ struct msm_context {
*/
int queueid;
+ /**
+ * @userspace_managed_vm:
+ *
+ * Has userspace opted-in to userspace managed VM (ie. VM_BIND) via
+ * MSM_PARAM_EN_VM_BIND?
+ */
+ bool userspace_managed_vm;
+
/**
* @vm:
*
@@ -446,6 +454,22 @@ struct msm_context {
struct drm_gpuvm *msm_context_vm(struct drm_device *dev, struct msm_context *ctx);
+/**
+ * msm_context_is_vm_bind() - has userspace opted in to VM_BIND?
+ *
+ * @ctx: the drm_file context
+ *
+ * See MSM_PARAM_EN_VM_BIND. If userspace is managing the VM, it can
+ * do sparse binding including having multiple, potentially partial,
+ * mappings in the VM. Therefore certain legacy uabi (ie. GET_IOVA,
+ * SET_IOVA) are rejected because they don't have a sensible meaning.
+ */
+static inline bool
+msm_context_is_vmbind(struct msm_context *ctx)
+{
+ return ctx->userspace_managed_vm;
+}
+
/**
* msm_gpu_convert_priority - Map userspace priority to ring # and sched priority
*
@@ -673,7 +697,8 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
const char *name, struct msm_gpu_config *config);
struct drm_gpuvm *
-msm_gpu_create_private_vm(struct msm_gpu *gpu, struct task_struct *task);
+msm_gpu_create_private_vm(struct msm_gpu *gpu, struct task_struct *task,
+ bool kernel_managed);
void msm_gpu_cleanup(struct msm_gpu *gpu);
diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index 2342cb90857e..072e82a80607 100644
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -91,6 +91,30 @@ struct drm_msm_timespec {
#define MSM_PARAM_UBWC_SWIZZLE 0x12 /* RO */
#define MSM_PARAM_MACROTILE_MODE 0x13 /* RO */
#define MSM_PARAM_UCHE_TRAP_BASE 0x14 /* RO */
+/* MSM_PARAM_EN_VM_BIND is set to 1 to enable VM_BIND ops.
+ *
+ * With VM_BIND enabled, userspace is required to allocate iova and use the
+ * VM_BIND ops for map/unmap ioctls. MSM_INFO_SET_IOVA and MSM_INFO_GET_IOVA
+ * will be rejected. (The latter does not have a sensible meaning when a BO
+ * can have multiple and/or partial mappings.)
+ *
+ * With VM_BIND enabled, userspace does not include a submit_bo table in the
+ * SUBMIT ioctl (this will be rejected), the resident set is determined by
+ * the the VM_BIND ops.
+ *
+ * Enabling VM_BIND will fail on devices which do not have per-process pgtables.
+ * And it is not allowed to disable VM_BIND once it has been enabled.
+ *
+ * Enabling VM_BIND should be done (attempted) prior to allocating any BOs or
+ * submitqueues of type MSM_SUBMITQUEUE_VM_BIND.
+ *
+ * Relatedly, when VM_BIND mode is enabled, the kernel will not try to recover
+ * from GPU faults or failed async VM_BIND ops, in particular because it is
+ * difficult to communicate to userspace which op failed so that userspace
+ * could rewind and try again. When the VM is marked unusable, the SUBMIT
+ * ioctl will throw -EPIPE.
+ */
+#define MSM_PARAM_EN_VM_BIND 0x15 /* WO, once */
/* For backwards compat. The original support for preemption was based on
* a single ring per priority level so # of priority levels equals the #
--
2.47.1
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