答复: 答复: [PATCH 1/2] drm/amdgpu: invalidate mmhub semphore workaround in amdgpu_virt
Liu, Monk
Monk.Liu at amd.com
Wed Nov 20 13:54:08 UTC 2019
Hah, but in SRIOV case, our guest KMD driver is not allowed to do such things .... (and even there is a bug that KMD try to power gate, the SMU firmware would not really do the jobs since
We have PSP L1 policy to prevent those danger operations )
Did Changfeng already hit this issue under SRIOV ???
-----邮件原件-----
发件人: Koenig, Christian <Christian.Koenig at amd.com>
发送时间: 2019年11月20日 21:21
收件人: Liu, Monk <Monk.Liu at amd.com>; Zhu, Changfeng <Changfeng.Zhu at amd.com>; Xiao, Jack <Jack.Xiao at amd.com>; Zhou1, Tao <Tao.Zhou1 at amd.com>; Huang, Ray <Ray.Huang at amd.com>; Huang, Shimmer <Xinmei.Huang at amd.com>; amd-gfx at lists.freedesktop.org
主题: Re: 答复: [PATCH 1/2] drm/amdgpu: invalidate mmhub semphore workaround in amdgpu_virt
Hi Monk,
this is a fix for power gating the MMHUB.
Basic problem is that the MMHUB can power gate while an invalidation is in progress which looses all bits in the ACK register and so deadlocks the engine waiting for the invalidation to finish.
This bug is hit immediately when we enable power gating of the MMHUB.
Regards,
Christian.
Am 20.11.19 um 14:18 schrieb Liu, Monk:
> Hi Changfeng
>
> Firs of all, there is no power-gating off circle involved in AMDGPU
> SRIOV, since we don't allow VF/VM do such things so I do feel strange
> why you post something like this Especially on VEGA10 serials which
> looks doesn't have any issue on those gpu_flush part
>
> Here is my questions for you:
> 1) Can you point me what issue had you been experienced ? and how to
> repro the bug
> 2) if you do hit some issues, did you verified that your patch can fix it ?
>
> besides
>
> /Monk
>
> -----邮件原件-----
> 发件人: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> 代表 Changfeng.Zhu
> 发送时间: 2019年11月20日 17:14
> 收件人: Koenig, Christian <Christian.Koenig at amd.com>; Xiao, Jack
> <Jack.Xiao at amd.com>; Zhou1, Tao <Tao.Zhou1 at amd.com>; Huang, Ray
> <Ray.Huang at amd.com>; Huang, Shimmer <Xinmei.Huang at amd.com>;
> amd-gfx at lists.freedesktop.org
> 抄送: Zhu, Changfeng <Changfeng.Zhu at amd.com>
> 主题: [PATCH 1/2] drm/amdgpu: invalidate mmhub semphore workaround in
> amdgpu_virt
>
> From: changzhu <Changfeng.Zhu at amd.com>
>
> It may lose gpuvm invalidate acknowldege state across power-gating off cycle. To avoid this issue in virt invalidation, add semaphore acquire before invalidation and semaphore release after invalidation.
>
> Change-Id: Ie98304e475166b53eed033462d76423b6b0fc25b
> Signed-off-by: changzhu <Changfeng.Zhu at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 26 ++++++++++++++++++++++-- drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h | 3 ++-
> drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 3 ++-
> 3 files changed, 28 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> index f04eb1a64271..70ffaf91cd12 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> @@ -135,7 +135,8 @@ void amdgpu_virt_kiq_wreg(struct amdgpu_device
> *adev, uint32_t reg, uint32_t v)
>
> void amdgpu_virt_kiq_reg_write_reg_wait(struct amdgpu_device *adev,
> uint32_t reg0, uint32_t reg1,
> - uint32_t ref, uint32_t mask)
> + uint32_t ref, uint32_t mask,
> + uint32_t sem)
> {
> struct amdgpu_kiq *kiq = &adev->gfx.kiq;
> struct amdgpu_ring *ring = &kiq->ring; @@ -144,9 +145,30 @@ void amdgpu_virt_kiq_reg_write_reg_wait(struct amdgpu_device *adev,
> uint32_t seq;
>
> spin_lock_irqsave(&kiq->ring_lock, flags);
> - amdgpu_ring_alloc(ring, 32);
> + amdgpu_ring_alloc(ring, 60);
> +
> + /*
> + * It may lose gpuvm invalidate acknowldege state across power-gating
> + * off cycle, add semaphore acquire before invalidation and semaphore
> + * release after invalidation to avoid entering power gated state
> + * to WA the Issue
> + */
> +
> + /* a read return value of 1 means semaphore acuqire */
> + if (ring->funcs->vmhub == AMDGPU_MMHUB_0 ||
> + ring->funcs->vmhub == AMDGPU_MMHUB_1)
> + amdgpu_ring_emit_reg_wait(ring, sem, 0x1, 0x1);
> +
> amdgpu_ring_emit_reg_write_reg_wait(ring, reg0, reg1,
> ref, mask);
> + /*
> + * add semaphore release after invalidation,
> + * write with 0 means semaphore release
> + */
> + if (ring->funcs->vmhub == AMDGPU_MMHUB_0 ||
> + ring->funcs->vmhub == AMDGPU_MMHUB_1)
> + amdgpu_ring_emit_wreg(ring, sem, 0);
> +
> amdgpu_fence_emit_polling(ring, &seq);
> amdgpu_ring_commit(ring);
> spin_unlock_irqrestore(&kiq->ring_lock, flags); diff --git
> a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> index b0b2bdc750df..bda6a2f37dc0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
> @@ -295,7 +295,8 @@ uint32_t amdgpu_virt_kiq_rreg(struct amdgpu_device *adev, uint32_t reg); void amdgpu_virt_kiq_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v); void amdgpu_virt_kiq_reg_write_reg_wait(struct amdgpu_device *adev,
> uint32_t reg0, uint32_t rreg1,
> - uint32_t ref, uint32_t mask);
> + uint32_t ref, uint32_t mask,
> + uint32_t sem);
> 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);
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index f25cd97ba5f2..1ae59af7836a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -448,9 +448,10 @@ static void gmc_v9_0_flush_gpu_tlb(struct amdgpu_device *adev, uint32_t vmid,
> !adev->in_gpu_reset) {
> uint32_t req = hub->vm_inv_eng0_req + eng;
> uint32_t ack = hub->vm_inv_eng0_ack + eng;
> + uint32_t sem = hub->vm_inv_eng0_sem + eng;
>
> amdgpu_virt_kiq_reg_write_reg_wait(adev, req, ack, tmp,
> - 1 << vmid);
> + 1 << vmid, sem);
> return;
> }
>
> --
> 2.17.1
>
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