Re: [RFC PATCH 5/6] arm/xen: Introduce xen_setup_dma_ops()

[Oleksandr <olekstysh@xxxxxxxxx>]

On 16.04.22 01:02, Stefano Stabellini wrote:

Hello Stefano

> On Thu, 14 Apr 2022, Oleksandr Tyshchenko wrote:
> > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> >
> > This patch introduces new helper and places it in new header.
> > The helper's purpose is to assign any Xen specific DMA ops in
> > a single place. For now, we deal with xen-swiotlb DMA ops only.
> > The subsequent patch will add xen-virtio DMA ops case.
> >
> > Also re-use the xen_swiotlb_detect() check on Arm32.
> Thanks for the patch, this is good to have in any case. I would move it
> to the beginning of the series.

ok, will move


> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> > ---
> >   arch/arm/include/asm/xen/xen-ops.h   |  1 +
> >   arch/arm/mm/dma-mapping.c            |  5 ++---
> >   arch/arm64/include/asm/xen/xen-ops.h |  1 +
> >   arch/arm64/mm/dma-mapping.c          |  5 ++---
> >   include/xen/arm/xen-ops.h            | 13 +++++++++++++
> >   5 files changed, 19 insertions(+), 6 deletions(-)
> >   create mode 100644 arch/arm/include/asm/xen/xen-ops.h
> >   create mode 100644 arch/arm64/include/asm/xen/xen-ops.h
> >   create mode 100644 include/xen/arm/xen-ops.h
> >
> > diff --git a/arch/arm/include/asm/xen/xen-ops.h 
> > b/arch/arm/include/asm/xen/xen-ops.h
> > new file mode 100644
> > index 00000000..8d2fa24
> > --- /dev/null
> > +++ b/arch/arm/include/asm/xen/xen-ops.h
> > @@ -0,0 +1 @@
> > +#include <xen/arm/xen-ops.h>
> > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> > index 82ffac6..a1bf9dd 100644
> > --- a/arch/arm/mm/dma-mapping.c
> > +++ b/arch/arm/mm/dma-mapping.c
> > @@ -33,7 +33,7 @@
> >   #include <asm/dma-iommu.h>
> >   #include <asm/mach/map.h>
> >   #include <asm/system_info.h>
> > -#include <xen/swiotlb-xen.h>
> > +#include <asm/xen/xen-ops.h>
> >   
> >   #include "dma.h"
> >   #include "mm.h"
> > @@ -2288,8 +2288,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, 
> > u64 size,
> >         set_dma_ops(dev, dma_ops);
> >   
> >   #ifdef CONFIG_XEN
> > -       if (xen_initial_domain())
> > -               dev->dma_ops = &xen_swiotlb_dma_ops;
> > +       xen_setup_dma_ops(dev);
> >   #endif
> You can take this opportunity to also remove the #ifdef, by providing an
> empty stub implemention of xen_setup_dma_ops for the !CONFIG_XEN case.

agree, will do


> >         dev->archdata.dma_ops_setup = true;
> >   }
> > diff --git a/arch/arm64/include/asm/xen/xen-ops.h 
> > b/arch/arm64/include/asm/xen/xen-ops.h
> > new file mode 100644
> > index 00000000..8d2fa24
> > --- /dev/null
> > +++ b/arch/arm64/include/asm/xen/xen-ops.h
> > @@ -0,0 +1 @@
> > +#include <xen/arm/xen-ops.h>
> > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> > index 6719f9e..831e673 100644
> > --- a/arch/arm64/mm/dma-mapping.c
> > +++ b/arch/arm64/mm/dma-mapping.c
> > @@ -9,9 +9,9 @@
> >   #include <linux/dma-map-ops.h>
> >   #include <linux/dma-iommu.h>
> >   #include <xen/xen.h>
> > -#include <xen/swiotlb-xen.h>
> >   
> >   #include <asm/cacheflush.h>
> > +#include <asm/xen/xen-ops.h>
> >   
> >   void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
> >                 enum dma_data_direction dir)
> > @@ -53,7 +53,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 
> > size,
> >                 iommu_setup_dma_ops(dev, dma_base, dma_base + size - 1);
> >   
> >   #ifdef CONFIG_XEN
> > -       if (xen_swiotlb_detect())
> > -               dev->dma_ops = &xen_swiotlb_dma_ops;
> > +       xen_setup_dma_ops(dev);
> >   #endif
> same here
ok


> >   }
> > diff --git a/include/xen/arm/xen-ops.h b/include/xen/arm/xen-ops.h
> > new file mode 100644
> > index 00000000..621da05
> > --- /dev/null
> > +++ b/include/xen/arm/xen-ops.h
> > @@ -0,0 +1,13 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_ARM_XEN_OPS_H
> > +#define _ASM_ARM_XEN_OPS_H
> > +
> > +#include <xen/swiotlb-xen.h>
> > +
> > +static inline void xen_setup_dma_ops(struct device *dev)
> > +{
> > +       if (xen_swiotlb_detect())
> > +               dev->dma_ops = &xen_swiotlb_dma_ops;
> > +}
> > +
> > +#endif /* _ASM_ARM_XEN_OPS_H */
> > --
> > 2.7.4
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
--
Regards,

Oleksandr Tyshchenko