From: Julien Grall <julien@xen.org>
To: Stefano Stabellini <sstabellini@kernel.org>,
jgross@suse.com, boris.ostrovsky@oracle.com,
konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org,
Stefano Stabellini <stefano.stabellini@xilinx.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/10] swiotlb-xen: introduce phys_to_dma/dma_to_phys translations
Date: Thu, 21 May 2020 09:07:53 +0100 [thread overview]
Message-ID: <0fa24e23-ee7a-3ff0-cee0-8734bcda5f6a@xen.org> (raw)
In-Reply-To: <20200520234520.22563-8-sstabellini@kernel.org>
Hi,
On 21/05/2020 00:45, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
>
> Call dma_to_phys in is_xen_swiotlb_buffer.
> Call phys_to_dma in xen_phys_to_bus.
> Call dma_to_phys in xen_bus_to_phys.
>
> Everything is taken care of by these changes except for
> xen_swiotlb_alloc_coherent and xen_swiotlb_free_coherent, which need a
> few explicit phys_to_dma/dma_to_phys calls.
The commit message explains what the code is doing but doesn't explain
why this is needed.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
> ---
> drivers/xen/swiotlb-xen.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index c50448fd9b75..d011c4c7aa72 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -64,14 +64,16 @@ static inline dma_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
>
> dma |= paddr & ~XEN_PAGE_MASK;
>
> - return dma;
> + return phys_to_dma(dev, dma);
> }
>
> -static inline phys_addr_t xen_bus_to_phys(struct device *dev, dma_addr_t baddr)
> +static inline phys_addr_t xen_bus_to_phys(struct device *dev,
> + dma_addr_t dma_addr)
> {
> + phys_addr_t baddr = dma_to_phys(dev, dma_addr);
> unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
> - dma_addr_t dma = (dma_addr_t)xen_pfn << XEN_PAGE_SHIFT;
> - phys_addr_t paddr = dma;
> + phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
> + (baddr & ~XEN_PAGE_MASK);
>
> paddr |= baddr & ~XEN_PAGE_MASK;
>
> @@ -99,7 +101,7 @@ static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
>
> static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
> {
> - unsigned long bfn = XEN_PFN_DOWN(dma_addr);
> + unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
> unsigned long xen_pfn = bfn_to_local_pfn(bfn);
> phys_addr_t paddr = XEN_PFN_PHYS(xen_pfn);
>
> @@ -304,11 +306,11 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> if (hwdev && hwdev->coherent_dma_mask)
> dma_mask = hwdev->coherent_dma_mask;
>
> - /* At this point dma_handle is the physical address, next we are
> + /* At this point dma_handle is the dma address, next we are
> * going to set it to the machine address.
> * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
> * to *dma_handle. */
> - phys = *dma_handle;
> + phys = dma_to_phys(hwdev, *dma_handle);
> dev_addr = xen_phys_to_bus(hwdev, phys);
> if (((dev_addr + size - 1 <= dma_mask)) &&
> !range_straddles_page_boundary(phys, size))
> @@ -319,6 +321,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
> return NULL;
> }
> + *dma_handle = phys_to_dma(hwdev, *dma_handle);
> SetPageXenRemapped(virt_to_page(ret));
> }
> memset(ret, 0, size);
> @@ -351,7 +354,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
> TestClearPageXenRemapped(pg))
> xen_destroy_contiguous_region(phys, order);
>
> - xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
> + xen_free_coherent_pages(hwdev, size, vaddr, phys_to_dma(hwdev, phys),
> + attrs);
> }
>
> /*
>
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2020-05-21 8:08 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 23:45 [PATCH 00/10] fix swiotlb-xen for RPi4 Stefano Stabellini
2020-05-20 23:45 ` [PATCH 01/10] swiotlb-xen: use vmalloc_to_page on vmalloc virt addresses Stefano Stabellini
2020-05-21 8:01 ` Julien Grall
2020-05-22 3:54 ` Stefano Stabellini
2020-05-22 18:11 ` Julien Grall
2020-05-22 20:36 ` Stefano Stabellini
2020-05-20 23:45 ` [PATCH 02/10] swiotlb-xen: remove start_dma_addr Stefano Stabellini
2020-05-21 8:05 ` Julien Grall
2020-05-22 3:55 ` Stefano Stabellini
2020-05-22 18:16 ` Julien Grall
2020-05-22 20:47 ` Stefano Stabellini
2020-05-20 23:45 ` [PATCH 03/10] swiotlb-xen: add struct device* parameter to xen_phys_to_bus Stefano Stabellini
2020-05-20 23:45 ` [PATCH 04/10] swiotlb-xen: add struct device* parameter to xen_bus_to_phys Stefano Stabellini
2020-05-20 23:45 ` [PATCH 05/10] swiotlb-xen: add struct device* parameter to xen_dma_sync_for_cpu Stefano Stabellini
2020-05-20 23:45 ` [PATCH 06/10] swiotlb-xen: add struct device* parameter to xen_dma_sync_for_device Stefano Stabellini
2020-05-20 23:45 ` [PATCH 07/10] swiotlb-xen: add struct device* parameter to is_xen_swiotlb_buffer Stefano Stabellini
2020-05-20 23:45 ` [PATCH 08/10] swiotlb-xen: introduce phys_to_dma/dma_to_phys translations Stefano Stabellini
2020-05-21 8:07 ` Julien Grall [this message]
2020-05-21 22:59 ` Boris Ostrovsky
2020-05-22 17:34 ` Stefano Stabellini
2020-05-22 18:29 ` Boris Ostrovsky
2020-05-20 23:45 ` [PATCH 09/10] xen/arm: introduce phys/dma translations in xen_dma_sync_for_* Stefano Stabellini
2020-05-21 8:18 ` Julien Grall
2020-05-21 20:08 ` Stefano Stabellini
2020-05-21 20:17 ` Julien Grall
2020-05-20 23:45 ` [PATCH 10/10] xen/arm: call dma_to_phys on the dma_addr_t parameter of dma_cache_maint Stefano Stabellini
2020-05-21 8:25 ` Julien Grall
2020-05-20 23:51 ` [PATCH 00/10] fix swiotlb-xen for RPi4 Roman Shaposhnik
2020-05-20 23:56 ` Stefano Stabellini
2020-06-02 21:51 ` Stefano Stabellini
2020-06-03 0:15 ` Boris Ostrovsky
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