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[PATCH v2] iommu/arm-smmu: disable PRR on SM8250

Dmitry Baryshkov posted 1 patch 3 months ago 
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
[PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Dmitry Baryshkov 3 months ago 
On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
because of the hyp limitations. Disable PRR support on that platform.

Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
I currently don't have access to other devices from these generations.
It might be necessary to apply the same workaround to other platforms.
---
Changes in v2:
- Simplify the workaround as the issue seems to be limited to SM8250
  only (Rob)
- Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	priv->set_prr_addr = NULL;
 
 	if (of_device_is_compatible(np, "qcom,smmu-500") &&
-			of_device_is_compatible(np, "qcom,adreno-smmu")) {
+	    !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
+	    of_device_is_compatible(np, "qcom,adreno-smmu")) {
 		priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
 		priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
 	}

---
base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
change-id: 20250705-iommu-fix-prr-600451b1d304

Best regards,
-- 
With best wishes
Dmitry
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Will Deacon 2 months, 3 weeks ago 
On Sat, 05 Jul 2025 19:08:33 +0300, Dmitry Baryshkov wrote:
> On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> because of the hyp limitations. Disable PRR support on that platform.
> 
> 

Applied to iommu (arm/smmu/updates), thanks!

[1/1] iommu/arm-smmu: disable PRR on SM8250
      https://git.kernel.org/iommu/c/b9bb7e814cd0

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Akhil P Oommen 3 months ago 
On 7/5/2025 9:38 PM, Dmitry Baryshkov wrote:
> On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> because of the hyp limitations. Disable PRR support on that platform.
> 
> Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>

Unfortunately, there is no way to detect firmware support for PRR safely
from KMD.

-Akhil.

> ---
> I currently don't have access to other devices from these generations.
> It might be necessary to apply the same workaround to other platforms.
> ---
> Changes in v2:
> - Simplify the workaround as the issue seems to be limited to SM8250
>   only (Rob)
> - Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
>  	priv->set_prr_addr = NULL;
>  
>  	if (of_device_is_compatible(np, "qcom,smmu-500") &&
> -			of_device_is_compatible(np, "qcom,adreno-smmu")) {
> +	    !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
> +	    of_device_is_compatible(np, "qcom,adreno-smmu")) {
>  		priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
>  		priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
>  	}
> 
> ---
> base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
> change-id: 20250705-iommu-fix-prr-600451b1d304
> 
> Best regards,
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Rob Clark 3 months ago 
On Sun, Jul 6, 2025 at 7:22 AM Akhil P Oommen <akhilpo@oss.qualcomm.com> wrote:
>
> On 7/5/2025 9:38 PM, Dmitry Baryshkov wrote:
> > On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> > because of the hyp limitations. Disable PRR support on that platform.
> >
> > Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>
> Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
>
> Unfortunately, there is no way to detect firmware support for PRR safely
> from KMD.

I still am a bit curious about whether it is the ACLTR write that
trips the fw out (doubtful, since we write other bits in that reg
AFAICT) or the PRR_CFG_LADDR/UADDR write that does it.  In the latter
case we could potentially use a reserved-region for the PRR page,
instead of dynamically allocating it (if we knew what values are in
LADDR/UADDR.. I guess 0x0?) to avoid reduced vk functionality on these
devices.  AFAIU the vk extensions that depend on PRR are required for
vkd3d.

BR,
-R

> -Akhil.
>
> > ---
> > I currently don't have access to other devices from these generations.
> > It might be necessary to apply the same workaround to other platforms.
> > ---
> > Changes in v2:
> > - Simplify the workaround as the issue seems to be limited to SM8250
> >   only (Rob)
> > - Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com
> > ---
> >  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > @@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
> >       priv->set_prr_addr = NULL;
> >
> >       if (of_device_is_compatible(np, "qcom,smmu-500") &&
> > -                     of_device_is_compatible(np, "qcom,adreno-smmu")) {
> > +         !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
> > +         of_device_is_compatible(np, "qcom,adreno-smmu")) {
> >               priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
> >               priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
> >       }
> >
> > ---
> > base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
> > change-id: 20250705-iommu-fix-prr-600451b1d304
> >
> > Best regards,
>
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Dmitry Baryshkov 3 months ago 
On Sun, 6 Jul 2025 at 18:20, Rob Clark <rob.clark@oss.qualcomm.com> wrote:
>
> On Sun, Jul 6, 2025 at 7:22 AM Akhil P Oommen <akhilpo@oss.qualcomm.com> wrote:
> >
> > On 7/5/2025 9:38 PM, Dmitry Baryshkov wrote:
> > > On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> > > because of the hyp limitations. Disable PRR support on that platform.
> > >
> > > Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> >
> > Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
> >
> > Unfortunately, there is no way to detect firmware support for PRR safely
> > from KMD.
>
> I still am a bit curious about whether it is the ACLTR write that
> trips the fw out (doubtful, since we write other bits in that reg
> AFAICT) or the PRR_CFG_LADDR/UADDR write that does it.

Indeed, write to ACTLR seems to go through, writes (or reads) to
PRR_CFG_[LU]ADDR cause a reset.

> In the latter
> case we could potentially use a reserved-region for the PRR page,
> instead of dynamically allocating it (if we knew what values are in
> LADDR/UADDR.. I guess 0x0?) to avoid reduced vk functionality on these
> devices.  AFAIU the vk extensions that depend on PRR are required for
> vkd3d.


-- 
With best wishes
Dmitry
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Rob Clark 3 months ago 
On Sun, Jul 6, 2025 at 9:38 AM Dmitry Baryshkov
<dmitry.baryshkov@oss.qualcomm.com> wrote:
>
> On Sun, 6 Jul 2025 at 18:20, Rob Clark <rob.clark@oss.qualcomm.com> wrote:
> >
> > On Sun, Jul 6, 2025 at 7:22 AM Akhil P Oommen <akhilpo@oss.qualcomm.com> wrote:
> > >
> > > On 7/5/2025 9:38 PM, Dmitry Baryshkov wrote:
> > > > On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> > > > because of the hyp limitations. Disable PRR support on that platform.
> > > >
> > > > Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> > > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> > >
> > > Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
> > >
> > > Unfortunately, there is no way to detect firmware support for PRR safely
> > > from KMD.
> >
> > I still am a bit curious about whether it is the ACLTR write that
> > trips the fw out (doubtful, since we write other bits in that reg
> > AFAICT) or the PRR_CFG_LADDR/UADDR write that does it.
>
> Indeed, write to ACTLR seems to go through, writes (or reads) to
> PRR_CFG_[LU]ADDR cause a reset.

ok, that is what I suspected.. I think if we can somehow figure out
what the inaccessible LADDR/UADDR values are, we can come up with a
reserved-region workaround

BR,
-R

> > In the latter
> > case we could potentially use a reserved-region for the PRR page,
> > instead of dynamically allocating it (if we knew what values are in
> > LADDR/UADDR.. I guess 0x0?) to avoid reduced vk functionality on these
> > devices.  AFAIU the vk extensions that depend on PRR are required for
> > vkd3d.
>
>
> --
> With best wishes
> Dmitry
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Rob Clark 3 months ago 
On Sun, Jul 6, 2025 at 8:20 AM Rob Clark <rob.clark@oss.qualcomm.com> wrote:
>
> On Sun, Jul 6, 2025 at 7:22 AM Akhil P Oommen <akhilpo@oss.qualcomm.com> wrote:
> >
> > On 7/5/2025 9:38 PM, Dmitry Baryshkov wrote:
> > > On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> > > because of the hyp limitations. Disable PRR support on that platform.
> > >
> > > Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> >
> > Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
> >
> > Unfortunately, there is no way to detect firmware support for PRR safely
> > from KMD.
>
> I still am a bit curious about whether it is the ACLTR write that
> trips the fw out (doubtful, since we write other bits in that reg
> AFAICT) or the PRR_CFG_LADDR/UADDR write that does it.  In the latter
> case we could potentially use a reserved-region for the PRR page,
> instead of dynamically allocating it (if we knew what values are in
> LADDR/UADDR.. I guess 0x0?) to avoid reduced vk functionality on these
> devices.  AFAIU the vk extensions that depend on PRR are required for
> vkd3d.

oh, and if it wasn't clear, that is something we can pursue, if
viable, after this patch is landed.  We kinda need this patch ASAP to
unbreak sm8250.

BR,
-R

> BR,
> -R
>
> > -Akhil.
> >
> > > ---
> > > I currently don't have access to other devices from these generations.
> > > It might be necessary to apply the same workaround to other platforms.
> > > ---
> > > Changes in v2:
> > > - Simplify the workaround as the issue seems to be limited to SM8250
> > >   only (Rob)
> > > - Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com
> > > ---
> > >  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > > index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
> > > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > > @@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
> > >       priv->set_prr_addr = NULL;
> > >
> > >       if (of_device_is_compatible(np, "qcom,smmu-500") &&
> > > -                     of_device_is_compatible(np, "qcom,adreno-smmu")) {
> > > +         !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
> > > +         of_device_is_compatible(np, "qcom,adreno-smmu")) {
> > >               priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
> > >               priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
> > >       }
> > >
> > > ---
> > > base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
> > > change-id: 20250705-iommu-fix-prr-600451b1d304
> > >
> > > Best regards,
> >
Re: [PATCH v2] iommu/arm-smmu: disable PRR on SM8250
Posted by Rob Clark 3 months ago 
On Sat, Jul 5, 2025 at 9:08 AM Dmitry Baryshkov
<dmitry.baryshkov@oss.qualcomm.com> wrote:
>
> On SM8250 / QRB5165-RB5 using PRR bits resets the device, most likely
> because of the hyp limitations. Disable PRR support on that platform.
>
> Fixes: 7f2ef1bfc758 ("iommu/arm-smmu: Add support for PRR bit setup")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Reviewed-by: Rob Clark <robin.clark@oss.qualcomm.com>

> ---
> I currently don't have access to other devices from these generations.
> It might be necessary to apply the same workaround to other platforms.
> ---
> Changes in v2:
> - Simplify the workaround as the issue seems to be limited to SM8250
>   only (Rob)
> - Link to v1: https://lore.kernel.org/r/20250705-iommu-fix-prr-v1-1-ef725033651c@oss.qualcomm.com
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 62874b18f6459ad9a8b0542ab81c24e3e745c53d..53d88646476e9f193a6275d9c3ee3d084c215362 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -355,7 +355,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
>         priv->set_prr_addr = NULL;
>
>         if (of_device_is_compatible(np, "qcom,smmu-500") &&
> -                       of_device_is_compatible(np, "qcom,adreno-smmu")) {
> +           !of_device_is_compatible(np, "qcom,sm8250-smmu-500") &&
> +           of_device_is_compatible(np, "qcom,adreno-smmu")) {
>                 priv->set_prr_bit = qcom_adreno_smmu_set_prr_bit;
>                 priv->set_prr_addr = qcom_adreno_smmu_set_prr_addr;
>         }
>
> ---
> base-commit: 7244e36657076b597ac21d118be9c0b0f15fc622
> change-id: 20250705-iommu-fix-prr-600451b1d304
>
> Best regards,
> --
> With best wishes
> Dmitry
>

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