Re: [Xen-devel] [PATCH v9 0/13] introduce GNTTABOP_cache_flush

Julien Grall
2014-11-12T14:22:26Z

Hi,

On 11/12/2014 11:39 AM, Stefano Stabellini wrote:
> Hi all,
> this patch series introduces support for GNTTABOP_cache_flush to perform
> cache maintenance operation on foreign pages and reverts the current
> code based on XENFEAT_grant_map_identity.
>
> It also provides a very slow fallback by bouncing on the swiotlb buffer,
> in case the hypercall is not available.
>
> v7 introduces a flag named dma_coherent in dev_archdata and an accessor
> function named is_device_dma_coherent in asm/dma-mapping.h under arm and
> arm64.

I've been tested this series on non-LPAE kernel and don't see crash anymore:

Tested-by: Julien Grall <julien.grall@linaro.org>

Regards,

> Changes in v9:
> - remove BUG_ON from the loop in dma_cache_maint;
> - add static inline for xen_dma_unmap_page, xen_dma_sync_single_for_cpu,
> xen_dma_sync_single_for_device;
> - map_page is always present, don't check whether it's implemented;
> - use bool local for clarity;
> - add an in-code comment.
>
> Changes in v8:
> - remove code duplication in mm32.c by moving the pfn_valid check in
> page-coherent.h;
> - add a dma_addr_t dev_addr argument to xen_dma_map_page;
> - use hypercall to flush caches in map_page;
> - pass dev_addr to xen_dma_unmap_page and xen_dma_sync_single_for_cpu;
> - remove BUG_ON in xen_bus_to_phys.
>
> Changes in v7:
> - rebased on 3.18-rc1;
> - rename is_dma_coherent to is_device_dma_coherent and move it to
> asm/dma-mapping.h on arm and arm64;
> - introduce a dma_coherent flag on arm and arm64;
> - set the flags from set_arch_dma_coherent_ops.
>
> Changes in v6:
> - rename xen_is_dma_coherent to is_dma_coherent;
> - use of_dma_is_coherent to detect the dma coherency of a device;
> - remove arch/arm64/include/asm/xen/page-coherent.h, include
> ../../arm/include/asm/xen/page-coherent.h instead;
> - fix indentation.
>
> Changes in v5:
> - introduce xen_is_dma_coherent as a xen specific function;
> - call xen_is_dma_coherent instead of is_dma_coherent;
> - introduce xen_is_dma_coherent to
> arch/arm64/include/asm/xen/page-coherent.h;
> - do not remove arch/arm64/include/asm/xen/page-coherent.h, add
> the missing dma_ops calls from it;
> - fix indentation;
> - rename hypercall_flush to hypercall_cflush;
> - remove spurious change.
>
> Changes in v4:
> - remove outer_*_range call;
> - introduce is_dma_coherent;
> - use is_dma_coherent in arch/arm/xen/mm32.c;
> - merge xen/mm32.c into xen/mm.c;
> - xen/arm/arm64: introduce xen_arch_need_swiotlb;
> - avoid bouncing dma map operations that involve foreign grants and
> non-coherent devices if GNTTABOP_cache_flush is provided by Xen.
>
> Changes in v3:
> - fix the cache maintenance op call to match what Linux does natively;
> - update the hypercall interface to match Xen.
>
> Changes in v2:
> - remove the definition of XENFEAT_grant_map_identity;
> - update the hypercall interface to match Xen;
> - call the interface on a single page at a time.
>
>
>
> git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen.git cache_flush_v9
>
> Stefano Stabellini (13):
> xen/arm: remove handling of XENFEAT_grant_map_identity
> xen/arm: remove outer_*_range call
> xen/arm: if(pfn_valid(pfn)) call native dma_ops
> arm64: introduce is_device_dma_coherent
> arm: introduce is_device_dma_coherent
> xen/arm: use is_device_dma_coherent
> xen: add a dma_addr_t dev_addr argument to xen_dma_map_page
> xen/arm: use hypercall to flush caches in map_page
> xen/arm/arm64: merge xen/mm32.c into xen/mm.c
> xen/arm/arm64: introduce xen_arch_need_swiotlb
> xen/arm: introduce GNTTABOP_cache_flush
> swiotlb-xen: pass dev_addr to xen_dma_unmap_page and xen_dma_sync_single_for_cpu
> swiotlb-xen: remove BUG_ON in xen_bus_to_phys
>
> arch/arm/include/asm/device.h | 1 +
> arch/arm/include/asm/dma-mapping.h | 6 +
> arch/arm/include/asm/xen/page-coherent.h | 66 +++++++--
> arch/arm/include/asm/xen/page.h | 4 +
> arch/arm/xen/Makefile | 2 +-
> arch/arm/xen/enlighten.c | 5 -
> arch/arm/xen/mm.c | 121 +++++++++++++++++
> arch/arm/xen/mm32.c | 202 ----------------------------
> arch/arm64/include/asm/device.h | 1 +
> arch/arm64/include/asm/dma-mapping.h | 6 +
> arch/arm64/include/asm/xen/page-coherent.h | 44 +-----
> arch/x86/include/asm/xen/page-coherent.h | 4 +-
> arch/x86/include/asm/xen/page.h | 7 +
> drivers/xen/swiotlb-xen.c | 19 +--
> include/xen/interface/features.h | 3 -
> include/xen/interface/grant_table.h | 19 +++
> 16 files changed, 237 insertions(+), 273 deletions(-)
> delete mode 100644 arch/arm/xen/mm32.c
>
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>

--
Julien Grall