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

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Date:   Sun, 17 Apr 2022 21:43:14 +0300
From:   Oleksandr <olekstysh@...il.com>
To:     Stefano Stabellini <sstabellini@...nel.org>
Cc:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        David Hildenbrand <david@...hat.com>,
        Martin Oliveira <martin.oliveira@...eticom.com>,
        Kees Cook <keescook@...omium.org>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        Julien Grall <julien@....org>,
        Christoph Hellwig <hch@...radead.org>,
        "Michael S. Tsirkin" <mst@...hat.com>
Subject: Re: [RFC PATCH 5/6] arm/xen: Introduce xen_setup_dma_ops()


On 16.04.22 01:02, Stefano Stabellini wrote:

Hello Stefano

> On Thu, 14 Apr 2022, Oleksandr Tyshchenko wrote:
>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
>>
>> 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@...m.com>
>> ---
>>   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@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
-- 
Regards,

Oleksandr Tyshchenko

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