[PATCH v2 2/3] s390/pci: store DMA offset in bus_dma_region

Matthew Rosato posted 3 patches 2 weeks ago
[PATCH v2 2/3] s390/pci: store DMA offset in bus_dma_region
Posted by Matthew Rosato 2 weeks ago
PCI devices on s390 have a DMA offset that is reported via CLP.  In
preparation for allowing identity domains, setup the bus_dma_region
for all PCI devices using the reported CLP value.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
 arch/s390/pci/pci_bus.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index d5ace00d10f0..14527687d0f2 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -19,6 +19,7 @@
 #include <linux/jump_label.h>
 #include <linux/pci.h>
 #include <linux/printk.h>
+#include <linux/dma-direct.h>
 
 #include <asm/pci_clp.h>
 #include <asm/pci_dma.h>
@@ -284,10 +285,27 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
 	return zbus;
 }
 
+static void pci_dma_range_setup(struct pci_dev *pdev)
+{
+	struct zpci_dev *zdev = to_zpci(pdev);
+	struct bus_dma_region *map;
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return;
+
+	map->cpu_start = 0;
+	map->dma_start = PAGE_ALIGN(zdev->start_dma);
+	map->size = (u64)virt_to_phys(high_memory);
+	pdev->dev.dma_range_map = map;
+}
+
 void pcibios_bus_add_device(struct pci_dev *pdev)
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
 
+	pci_dma_range_setup(pdev);
+
 	/*
 	 * With pdev->no_vf_scan the common PCI probing code does not
 	 * perform PF/VF linking.
-- 
2.47.1
Re: [PATCH v2 2/3] s390/pci: store DMA offset in bus_dma_region
Posted by Niklas Schnelle 1 week, 4 days ago
On Fri, 2024-12-13 at 17:49 -0500, Matthew Rosato wrote:
> PCI devices on s390 have a DMA offset that is reported via CLP.  In
> preparation for allowing identity domains, setup the bus_dma_region
> for all PCI devices using the reported CLP value.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>  arch/s390/pci/pci_bus.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
> index d5ace00d10f0..14527687d0f2 100644
> --- a/arch/s390/pci/pci_bus.c
> +++ b/arch/s390/pci/pci_bus.c
> @@ -19,6 +19,7 @@
>  #include <linux/jump_label.h>
>  #include <linux/pci.h>
>  #include <linux/printk.h>
> +#include <linux/dma-direct.h>
>  
>  #include <asm/pci_clp.h>
>  #include <asm/pci_dma.h>
> @@ -284,10 +285,27 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
>  	return zbus;
>  }
>  
> +static void pci_dma_range_setup(struct pci_dev *pdev)
> +{
> +	struct zpci_dev *zdev = to_zpci(pdev);
> +	struct bus_dma_region *map;
> +
> +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> +	if (!map)
> +		return;
> +
> +	map->cpu_start = 0;
> +	map->dma_start = PAGE_ALIGN(zdev->start_dma);
> +	map->size = (u64)virt_to_phys(high_memory);

I don't think we should restrict the size here to the size of memory.
Instead I think it should be zdev->end_dma - zdev->start_dma.

Since we handle the restriction to memory size as reserved regions I
think that should be compatible. Also I think otherwise this might
break the admittedly odd s390_iommu_aperture=X kernel parameter on
LPARs.


> +	pdev->dev.dma_range_map = map;
> +}
> +
>  void pcibios_bus_add_device(struct pci_dev *pdev)
>  {
>  	struct zpci_dev *zdev = to_zpci(pdev);
>  
> +	pci_dma_range_setup(pdev);
> +
>  	/*
>  	 * With pdev->no_vf_scan the common PCI probing code does not
>  	 * perform PF/VF linking.
Re: [PATCH v2 2/3] s390/pci: store DMA offset in bus_dma_region
Posted by Niklas Schnelle 1 week, 4 days ago
On Mon, 2024-12-16 at 10:29 +0100, Niklas Schnelle wrote:
> On Fri, 2024-12-13 at 17:49 -0500, Matthew Rosato wrote:
> > PCI devices on s390 have a DMA offset that is reported via CLP.  In
> > preparation for allowing identity domains, setup the bus_dma_region
> > for all PCI devices using the reported CLP value.
> > 
> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > ---
> >  arch/s390/pci/pci_bus.c | 18 ++++++++++++++++++
> >  1 file changed, 18 insertions(+)
> > 
> > diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
> > index d5ace00d10f0..14527687d0f2 100644
> > --- a/arch/s390/pci/pci_bus.c
> > +++ b/arch/s390/pci/pci_bus.c
> > @@ -19,6 +19,7 @@
> >  #include <linux/jump_label.h>
> >  #include <linux/pci.h>
> >  #include <linux/printk.h>
> > +#include <linux/dma-direct.h>
> >  
> >  #include <asm/pci_clp.h>
> >  #include <asm/pci_dma.h>
> > @@ -284,10 +285,27 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
> >  	return zbus;
> >  }
> >  
> > +static void pci_dma_range_setup(struct pci_dev *pdev)
> > +{
> > +	struct zpci_dev *zdev = to_zpci(pdev);
> > +	struct bus_dma_region *map;
> > +
> > +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> > +	if (!map)
> > +		return;
> > +
> > +	map->cpu_start = 0;
> > +	map->dma_start = PAGE_ALIGN(zdev->start_dma);
> > +	map->size = (u64)virt_to_phys(high_memory);
> 
> I don't think we should restrict the size here to the size of memory.
> Instead I think it should be zdev->end_dma - zdev->start_dma.
> 
> Since we handle the restriction to memory size as reserved regions I
> think that should be compatible. Also I think otherwise this might
> break the admittedly odd s390_iommu_aperture=X kernel parameter on
> LPARs.

Correction, zdev->end_dma - zdev->start_dma + 1 because zdev->end_dma
is inclusive ;-)

> 
> 
> > +	pdev->dev.dma_range_map = map;
> > +}
> > +
> >  void pcibios_bus_add_device(struct pci_dev *pdev)
> >  {
> >  	struct zpci_dev *zdev = to_zpci(pdev);
> >  
> > +	pci_dma_range_setup(pdev);
> > +
> >  	/*
> >  	 * With pdev->no_vf_scan the common PCI probing code does not
> >  	 * perform PF/VF linking.
> 
Re: [PATCH v2 2/3] s390/pci: store DMA offset in bus_dma_region
Posted by Matthew Rosato 1 week, 4 days ago
>>> +	map->cpu_start = 0;
>>> +	map->dma_start = PAGE_ALIGN(zdev->start_dma);
>>> +	map->size = (u64)virt_to_phys(high_memory);
>>
>> I don't think we should restrict the size here to the size of memory.
>> Instead I think it should be zdev->end_dma - zdev->start_dma.
>>
>> Since we handle the restriction to memory size as reserved regions I
>> think that should be compatible. Also I think otherwise this might
>> break the admittedly odd s390_iommu_aperture=X kernel parameter on
>> LPARs.
> 
> Correction, zdev->end_dma - zdev->start_dma + 1 because zdev->end_dma
> is inclusive ;-)
> 

Forgot about that parameter, thanks...  OK, will change to:

map->size = zdev->end_dma - zdev->start_dma + 1;