Re: [PATCH 10/10] xen/arm: call dma_to_phys on the dma_addr_t parameter of dma_cache_maint

From: Julien Grall
Date: Thu May 21 2020 - 04:26:02 EST




On 21/05/2020 00:45, Stefano Stabellini wrote:
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

Add a struct device* parameter to dma_cache_maint.

Translate the dma_addr_t parameter of dma_cache_maint by calling
dma_to_phys. Do it for the first page and all the following pages, in
case of multipage handling.

The term 'page' is confusing here. Are we referring to Xen page or Linux page?

Also, same as patch #8 and #9 regarding the commit message.


Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
---
arch/arm/xen/mm.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 7639251bcc79..6ddf3b3c1ab5 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -43,15 +43,18 @@ unsigned long xen_get_swiotlb_free_pages(unsigned int order)
static bool hypercall_cflush = false;
/* buffers in highmem or foreign pages cannot cross page boundaries */
-static void dma_cache_maint(dma_addr_t handle, size_t size, u32 op)
+static void dma_cache_maint(struct device *dev, dma_addr_t handle,
+ size_t size, u32 op)
{
struct gnttab_cache_flush cflush;
- cflush.a.dev_bus_addr = handle & XEN_PAGE_MASK;
cflush.offset = xen_offset_in_page(handle);
cflush.op = op;
+ handle &= XEN_PAGE_MASK;
do {
+ cflush.a.dev_bus_addr = dma_to_phys(dev, handle);
+
if (size + cflush.offset > XEN_PAGE_SIZE)
cflush.length = XEN_PAGE_SIZE - cflush.offset;
else
@@ -60,7 +63,7 @@ static void dma_cache_maint(dma_addr_t handle, size_t size, u32 op)
HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);
cflush.offset = 0;
- cflush.a.dev_bus_addr += cflush.length;
+ handle += cflush.length;
size -= cflush.length;
} while (size);
}
@@ -79,7 +82,7 @@ void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
if (pfn_valid(PFN_DOWN(dma_to_phys(dev, handle))))
arch_sync_dma_for_cpu(paddr, size, dir);
else if (dir != DMA_TO_DEVICE)
- dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL);
+ dma_cache_maint(dev, handle, size, GNTTAB_CACHE_INVAL);
}
void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
@@ -89,9 +92,9 @@ void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
if (pfn_valid(PFN_DOWN(dma_to_phys(dev, handle))))
arch_sync_dma_for_device(paddr, size, dir);
else if (dir == DMA_FROM_DEVICE)
- dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL);
+ dma_cache_maint(dev, handle, size, GNTTAB_CACHE_INVAL);
else
- dma_cache_maint(handle, size, GNTTAB_CACHE_CLEAN);
+ dma_cache_maint(dev, handle, size, GNTTAB_CACHE_CLEAN);
}
bool xen_arch_need_swiotlb(struct device *dev,


Cheers,

--
Julien Grall