Re: [PATCH] drm/amdkfd: only allow heavy-weight TLB flush on some ASICs for SVM too

[Lang Yu <Lang.Yu@amd.com>]

On 04/14/ , Felix Kuehling wrote:
> 
> Am 2022-04-14 um 04:19 schrieb Lang Yu:
> > The idea is from commit a50fe7078035 ("drm/amdkfd: Only apply heavy-weight
> > TLB flush on Aldebaran") and commit f61c40c0757a ("drm/amdkfd: enable
> > heavy-weight TLB flush on Arcturus"). Otherwise, we will run into problems
> > on some ASICs when running SVM applications.
> > 
> > Signed-off-by: Lang Yu <Lang.Yu@amd.com>
> > ---
> >   drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 8 --------
> >   drivers/gpu/drm/amd/amdkfd/kfd_priv.h    | 8 ++++++++
> >   drivers/gpu/drm/amd/amdkfd/kfd_svm.c     | 4 +++-
> >   3 files changed, 11 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > index 91f82a9ccdaf..459f59e3d0ed 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > @@ -1128,14 +1128,6 @@ static int kfd_ioctl_free_memory_of_gpu(struct file *filep,
> >   	return ret;
> >   }
> > -static bool kfd_flush_tlb_after_unmap(struct kfd_dev *dev)
> > -{
> > -	return KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 2) ||
> > -		(KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 1) &&
> > -		dev->adev->sdma.instance[0].fw_version >= 18) ||
> > -		KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 0);
> > -}
> > -
> >   static int kfd_ioctl_map_memory_to_gpu(struct file *filep,
> >   					struct kfd_process *p, void *data)
> >   {
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > index 8a43def1f638..aff6f598ff2c 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > @@ -1328,6 +1328,14 @@ void kfd_signal_poison_consumed_event(struct kfd_dev *dev, u32 pasid);
> >   void kfd_flush_tlb(struct kfd_process_device *pdd, enum TLB_FLUSH_TYPE type);
> > +static inline bool kfd_flush_tlb_after_unmap(struct kfd_dev *dev)
> > +{
> > +	return KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 2) ||
> > +	       (KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 1) &&
> > +	       dev->adev->sdma.instance[0].fw_version >= 18) ||
> > +	       KFD_GC_VERSION(dev) == IP_VERSION(9, 4, 0);
> > +}
> > +
> >   bool kfd_is_locked(void);
> >   /* Compute profile */
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > index 459fa07a3bcc..5afe216cf099 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > @@ -1229,7 +1229,9 @@ svm_range_unmap_from_gpus(struct svm_range *prange, unsigned long start,
> >   			if (r)
> >   				break;
> >   		}
> > -		kfd_flush_tlb(pdd, TLB_FLUSH_HEAVYWEIGHT);
> > +
> > +		if (kfd_flush_tlb_after_unmap(pdd->dev))
> > +			kfd_flush_tlb(pdd, TLB_FLUSH_HEAVYWEIGHT);
> 
> Then you probably need to add another flush_tlb call in
> svm_range_map_to_gpus.

There is a TLB_FLUSH_LEGACY call in svm_range_map_to_gpus same with
kfd_ioctl_map_memory_to_gpu. Do we still need to add another one?

Regards,
Lang

> Regards,
>   Felix
> 
> 
> >   	}
> >   	return r;