Re: [PATCH v2 02/10] drm/amdgpu: fix sriov host flr handler

["Christian König" <christian.koenig@amd.com>]

Am 28.05.24 um 19:23 schrieb Yunxiang Li:
> We send back the ready to reset message before we stop anything. This is
> wrong. Move it to when we are actually ready for the FLR to happen.
>
> In the current state since we take tens of seconds to stop everything,
> it is very likely that host would give up waiting and reset the GPU
> before we send ready, so it would be the same as before. But this gets
> rid of the hack with reset_domain locking and also let us know how slow
> the reset actually is on the host. The pre-reset speed can thus be
> improved later.
>
> Signed-off-by: Yunxiang Li <Yunxiang.Li@amd.com>

It looks like a nice cleanup to me, but that is absolutely not my field 
of expertise.

But feel free to add an Acked-by: Christian König <christian.koenig@amd.com>

Regards,
Christian.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  2 ++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c   | 14 ++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h   |  2 ++
>   drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c      | 37 ++++++++--------------
>   drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c      | 37 ++++++++--------------
>   drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c      |  6 ----
>   6 files changed, 46 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index bf1a6593dc5e..eb77b4ec3cb4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -5069,6 +5069,8 @@ static int amdgpu_device_reset_sriov(struct amdgpu_device *adev,
>   	struct amdgpu_hive_info *hive = NULL;
>   
>   	if (test_bit(AMDGPU_HOST_FLR, &reset_context->flags)) {
> +		amdgpu_virt_ready_to_reset(adev);
> +		amdgpu_virt_wait_reset(adev);
>   		clear_bit(AMDGPU_HOST_FLR, &reset_context->flags);
>   		r = amdgpu_virt_request_full_gpu(adev, true);
>   	} else {
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> index 3cf8416f8cb0..44450507c140 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> @@ -152,6 +152,20 @@ void amdgpu_virt_request_init_data(struct amdgpu_device *adev)
>   		DRM_WARN("host doesn't support REQ_INIT_DATA handshake\n");
>   }
>   
> +/**
> + * amdgpu_virt_ready_to_reset() - send ready to reset to host
> + * @adev:	amdgpu device.
> + * Send ready to reset message to GPU hypervisor to signal we have stopped GPU
> + * activity and is ready for host FLR
> + */
> +void amdgpu_virt_ready_to_reset(struct amdgpu_device *adev)
> +{
> +	struct amdgpu_virt *virt = &adev->virt;
> +
> +	if (virt->ops && virt->ops->reset_gpu)
> +		virt->ops->ready_to_reset(adev);
> +}
> +
>   /**
>    * amdgpu_virt_wait_reset() - wait for reset gpu completed
>    * @adev:	amdgpu device.
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> index 642f1fd287d8..66de5380d9a1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> @@ -88,6 +88,7 @@ struct amdgpu_virt_ops {
>   	int (*rel_full_gpu)(struct amdgpu_device *adev, bool init);
>   	int (*req_init_data)(struct amdgpu_device *adev);
>   	int (*reset_gpu)(struct amdgpu_device *adev);
> +	void (*ready_to_reset)(struct amdgpu_device *adev);
>   	int (*wait_reset)(struct amdgpu_device *adev);
>   	void (*trans_msg)(struct amdgpu_device *adev, enum idh_request req,
>   			  u32 data1, u32 data2, u32 data3);
> @@ -345,6 +346,7 @@ int amdgpu_virt_request_full_gpu(struct amdgpu_device *adev, bool init);
>   int amdgpu_virt_release_full_gpu(struct amdgpu_device *adev, bool init);
>   int amdgpu_virt_reset_gpu(struct amdgpu_device *adev);
>   void amdgpu_virt_request_init_data(struct amdgpu_device *adev);
> +void amdgpu_virt_ready_to_reset(struct amdgpu_device *adev);
>   int amdgpu_virt_wait_reset(struct amdgpu_device *adev);
>   int amdgpu_virt_alloc_mm_table(struct amdgpu_device *adev);
>   void amdgpu_virt_free_mm_table(struct amdgpu_device *adev);
> diff --git a/drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c b/drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c
> index f4c47492e0cd..3fdd1fc84723 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mxgpu_ai.c
> @@ -249,38 +249,28 @@ static int xgpu_ai_set_mailbox_ack_irq(struct amdgpu_device *adev,
>   	return 0;
>   }
>   
> -static void xgpu_ai_mailbox_flr_work(struct work_struct *work)
> +static void xgpu_ai_ready_to_reset(struct amdgpu_device *adev)
>   {
> -	struct amdgpu_virt *virt = container_of(work, struct amdgpu_virt, flr_work);
> -	struct amdgpu_device *adev = container_of(virt, struct amdgpu_device, virt);
> -	int timeout = AI_MAILBOX_POLL_FLR_TIMEDOUT;
> -
> -	/* block amdgpu_gpu_recover till msg FLR COMPLETE received,
> -	 * otherwise the mailbox msg will be ruined/reseted by
> -	 * the VF FLR.
> -	 */
> -	if (atomic_cmpxchg(&adev->reset_domain->in_gpu_reset, 0, 1) != 0)
> -		return;
> -
> -	down_write(&adev->reset_domain->sem);
> -
> -	amdgpu_virt_fini_data_exchange(adev);
> -
>   	xgpu_ai_mailbox_trans_msg(adev, IDH_READY_TO_RESET, 0, 0, 0);
> +}
>   
> +static int xgpu_ai_wait_reset(struct amdgpu_device *adev)
> +{
> +	int timeout = AI_MAILBOX_POLL_FLR_TIMEDOUT;
>   	do {
>   		if (xgpu_ai_mailbox_peek_msg(adev) == IDH_FLR_NOTIFICATION_CMPL)
> -			goto flr_done;
> -
> +			return 0;
>   		msleep(10);
>   		timeout -= 10;
>   	} while (timeout > 1);
> -
>   	dev_warn(adev->dev, "waiting IDH_FLR_NOTIFICATION_CMPL timeout\n");
> +	return -ETIME;
> +}
>   
> -flr_done:
> -	atomic_set(&adev->reset_domain->in_gpu_reset, 0);
> -	up_write(&adev->reset_domain->sem);
> +static void xgpu_ai_mailbox_flr_work(struct work_struct *work)
> +{
> +	struct amdgpu_virt *virt = container_of(work, struct amdgpu_virt, flr_work);
> +	struct amdgpu_device *adev = container_of(virt, struct amdgpu_device, virt);
>   
>   	/* Trigger recovery for world switch failure if no TDR */
>   	if (amdgpu_device_should_recover_gpu(adev)
> @@ -417,7 +407,8 @@ const struct amdgpu_virt_ops xgpu_ai_virt_ops = {
>   	.req_full_gpu	= xgpu_ai_request_full_gpu_access,
>   	.rel_full_gpu	= xgpu_ai_release_full_gpu_access,
>   	.reset_gpu = xgpu_ai_request_reset,
> -	.wait_reset = NULL,
> +	.ready_to_reset = xgpu_ai_ready_to_reset,
> +	.wait_reset = xgpu_ai_wait_reset,
>   	.trans_msg = xgpu_ai_mailbox_trans_msg,
>   	.req_init_data  = xgpu_ai_request_init_data,
>   	.ras_poison_handler = xgpu_ai_ras_poison_handler,
> diff --git a/drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c b/drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c
> index 37b49a5ed2a1..cd6ec1afff2b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c
> @@ -282,38 +282,28 @@ static int xgpu_nv_set_mailbox_ack_irq(struct amdgpu_device *adev,
>   	return 0;
>   }
>   
> -static void xgpu_nv_mailbox_flr_work(struct work_struct *work)
> +static void xgpu_nv_ready_to_reset(struct amdgpu_device *adev)
>   {
> -	struct amdgpu_virt *virt = container_of(work, struct amdgpu_virt, flr_work);
> -	struct amdgpu_device *adev = container_of(virt, struct amdgpu_device, virt);
> -	int timeout = NV_MAILBOX_POLL_FLR_TIMEDOUT;
> -
> -	/* block amdgpu_gpu_recover till msg FLR COMPLETE received,
> -	 * otherwise the mailbox msg will be ruined/reseted by
> -	 * the VF FLR.
> -	 */
> -	if (atomic_cmpxchg(&adev->reset_domain->in_gpu_reset, 0, 1) != 0)
> -		return;
> -
> -	down_write(&adev->reset_domain->sem);
> -
> -	amdgpu_virt_fini_data_exchange(adev);
> -
>   	xgpu_nv_mailbox_trans_msg(adev, IDH_READY_TO_RESET, 0, 0, 0);
> +}
>   
> +static int xgpu_nv_wait_reset(struct amdgpu_device *adev)
> +{
> +	int timeout = NV_MAILBOX_POLL_FLR_TIMEDOUT;
>   	do {
>   		if (xgpu_nv_mailbox_peek_msg(adev) == IDH_FLR_NOTIFICATION_CMPL)
> -			goto flr_done;
> -
> +			return 0;
>   		msleep(10);
>   		timeout -= 10;
>   	} while (timeout > 1);
> -
>   	dev_warn(adev->dev, "waiting IDH_FLR_NOTIFICATION_CMPL timeout\n");
> +	return -ETIME;
> +}
>   
> -flr_done:
> -	atomic_set(&adev->reset_domain->in_gpu_reset, 0);
> -	up_write(&adev->reset_domain->sem);
> +static void xgpu_nv_mailbox_flr_work(struct work_struct *work)
> +{
> +	struct amdgpu_virt *virt = container_of(work, struct amdgpu_virt, flr_work);
> +	struct amdgpu_device *adev = container_of(virt, struct amdgpu_device, virt);
>   
>   	/* Trigger recovery for world switch failure if no TDR */
>   	if (amdgpu_device_should_recover_gpu(adev)
> @@ -455,7 +445,8 @@ const struct amdgpu_virt_ops xgpu_nv_virt_ops = {
>   	.rel_full_gpu	= xgpu_nv_release_full_gpu_access,
>   	.req_init_data  = xgpu_nv_request_init_data,
>   	.reset_gpu = xgpu_nv_request_reset,
> -	.wait_reset = NULL,
> +	.ready_to_reset = xgpu_nv_ready_to_reset,
> +	.wait_reset = xgpu_nv_wait_reset,
>   	.trans_msg = xgpu_nv_mailbox_trans_msg,
>   	.ras_poison_handler = xgpu_nv_ras_poison_handler,
>   };
> diff --git a/drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c b/drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c
> index 78cd07744ebe..e1d63bed84bf 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mxgpu_vi.c
> @@ -515,12 +515,6 @@ static void xgpu_vi_mailbox_flr_work(struct work_struct *work)
>   	struct amdgpu_virt *virt = container_of(work, struct amdgpu_virt, flr_work);
>   	struct amdgpu_device *adev = container_of(virt, struct amdgpu_device, virt);
>   
> -	/* wait until RCV_MSG become 3 */
> -	if (xgpu_vi_poll_msg(adev, IDH_FLR_NOTIFICATION_CMPL)) {
> -		pr_err("failed to receive FLR_CMPL\n");
> -		return;
> -	}
> -
>   	/* Trigger recovery due to world switch failure */
>   	if (amdgpu_device_should_recover_gpu(adev)) {
>   		struct amdgpu_reset_context reset_context;