[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xen/arm and swiotlb-xen: possible data corruption
On 02/03/2017 22:39, Stefano Stabellini wrote: On Thu, 2 Mar 2017, Julien Grall wrote:Hi Stefano, On 02/03/17 19:12, Stefano Stabellini wrote:On Thu, 2 Mar 2017, Julien Grall wrote:On 02/03/17 08:53, Edgar E. Iglesias wrote:On Thu, Mar 02, 2017 at 09:38:37AM +0100, Edgar E. Iglesias wrote:On Wed, Mar 01, 2017 at 05:05:21PM -0800, Stefano Stabellini wrote:Julien, from looking at the two diffs, this is simpler and nicer, but if you look at xen/include/asm-arm/page.h, my patch made clean_dcache_va_range consistent with invalidate_dcache_va_range. For consistency, I would prefer to deal with the two functions the same way. Although it is not a spec requirement, I also think that it is a good idea to issue cache flushes from cacheline aligned addresses, like invalidate_dcache_va_range does and Linux does, to make more obvious what is going on.invalid_dcache_va_range is split because the cache instruction differs for the start and end if unaligned. For them you want to use clean & invalidate rather than invalidate. If you look at the implementation of other cache helpers in Linux (see dcache_by_line_op in arch/arm64/include/asm/assembler.h), they will only align start & end.I don't think so, unless I am reading dcache_by_line_op wrong. 343 .macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2 344 dcache_line_size \tmp1, \tmp2 345 add \size, \kaddr, \size 346 sub \tmp2, \tmp1, #1 347 bic \kaddr, \kaddr, \tmp2 348 9998: 349 .if (\op == cvau || \op == cvac) 350 alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE 351 dc \op, \kaddr 352 alternative_else 353 dc civac, \kaddr 354 alternative_endif 355 .else 356 dc \op, \kaddr 357 .endif 358 add \kaddr, \kaddr, \tmp1 359 cmp \kaddr, \size 360 b.lo 9998b 361 dsb \domain 362 .endm 363It has only one cache instruction in the resulting assembly because it has .if/.else assembly directives. Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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