Re: [PATCH 1/2] xen/swiotlb: Pass addresses rather than frame numbers to xen_arch_need_swiotlb

[Stefano Stabellini]

On Thu, 10 Sep 2015, Julien Grall wrote:
> With 64KB page granularity support, the frame number will be different.
> 
> It will be easier to modify the behavior in a single place rather than
> in each caller.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> 

Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> ---
>  arch/arm/include/asm/xen/page.h | 4 ++--
>  arch/arm/xen/mm.c               | 7 +++++--
>  arch/x86/include/asm/xen/page.h | 4 ++--
>  drivers/xen/swiotlb-xen.c       | 4 ++--
>  4 files changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
> index e3d94cf..415dbc6 100644
> --- a/arch/arm/include/asm/xen/page.h
> +++ b/arch/arm/include/asm/xen/page.h
> @@ -115,8 +115,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
>  #define xen_unmap(cookie) iounmap((cookie))
>  
>  bool xen_arch_need_swiotlb(struct device *dev,
> -			   unsigned long pfn,
> -			   unsigned long bfn);
> +			   phys_addr_t phys,
> +			   dma_addr_t dev_addr);
>  unsigned long xen_get_swiotlb_free_pages(unsigned int order);
>  
>  #endif /* _ASM_ARM_XEN_PAGE_H */
> diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> index 6dd911d..7b517e91 100644
> --- a/arch/arm/xen/mm.c
> +++ b/arch/arm/xen/mm.c
> @@ -138,9 +138,12 @@ void __xen_dma_sync_single_for_device(struct device *hwdev,
>  }
>  
>  bool xen_arch_need_swiotlb(struct device *dev,
> -			   unsigned long pfn,
> -			   unsigned long bfn)
> +			   phys_addr_t phys,
> +			   dma_addr_t dev_addr)
>  {
> +	unsigned long pfn = PFN_DOWN(phys);
> +	unsigned long bfn = PFN_DOWN(dev_addr);
> +
>  	return (!hypercall_cflush && (pfn != bfn) && !is_device_dma_coherent(dev));
>  }
>  
> diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> index 2a05e691..84c4757 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -296,8 +296,8 @@ void make_lowmem_page_readwrite(void *vaddr);
>  #define xen_unmap(cookie) iounmap((cookie))
>  
>  static inline bool xen_arch_need_swiotlb(struct device *dev,
> -					 unsigned long pfn,
> -					 unsigned long bfn)
> +					 phys_addr_t phys,
> +					 dma_addr_t dev_addr);
>  {
>  	return false;
>  }
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index d757a3e..cfe755d 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -398,7 +398,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>  	 */
>  	if (dma_capable(dev, dev_addr, size) &&
>  	    !range_straddles_page_boundary(phys, size) &&
> -		!xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) &&
> +		!xen_arch_need_swiotlb(dev, phys, dev_addr) &&
>  		!swiotlb_force) {
>  		/* we are not interested in the dma_addr returned by
>  		 * xen_dma_map_page, only in the potential cache flushes executed
> @@ -557,7 +557,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
>  		dma_addr_t dev_addr = xen_phys_to_bus(paddr);
>  
>  		if (swiotlb_force ||
> -		    xen_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) ||
> +		    xen_arch_need_swiotlb(hwdev, paddr, dev_addr) ||
>  		    !dma_capable(hwdev, dev_addr, sg->length) ||
>  		    range_straddles_page_boundary(paddr, sg->length)) {
>  			phys_addr_t map = swiotlb_tbl_map_single(hwdev,
> -- 
> 2.1.4
> 
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