Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752797AbaKLLsF (ORCPT ); Wed, 12 Nov 2014 06:48:05 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:62772 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752697AbaKLLsC (ORCPT ); Wed, 12 Nov 2014 06:48:02 -0500 X-IronPort-AV: E=Sophos;i="5.07,368,1413244800"; d="scan'208";a="191922247" From: Stefano Stabellini To: CC: , , , , , , , Stefano Stabellini Subject: [PATCH v9 11/13] xen/arm: introduce GNTTABOP_cache_flush Date: Wed, 12 Nov 2014 11:40:52 +0000 Message-ID: <1415792454-23161-11-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce support for new hypercall GNTTABOP_cache_flush. Use it to perform cache flashing on pages used for dma when necessary. If GNTTABOP_cache_flush is supported by the hypervisor, we don't need to bounce dma map operations that involve foreign grants and non-coherent devices. Signed-off-by: Stefano Stabellini Reviewed-by: Catalin Marinas Acked-by: Ian Campbell --- Changes in v5: - rename hypercall_flush to hypercall_cflush; - remove spurious change. Changes in v4: - add comment; - 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: - update the hypercall interface to match Xen; - call the interface on a single page at a time. --- arch/arm/xen/mm.c | 34 ++++++++++++++++++++++++++++++++-- include/xen/interface/grant_table.h | 19 +++++++++++++++++++ 2 files changed, 51 insertions(+), 2 deletions(-) diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 28ebf3e..351b24a 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -12,6 +12,7 @@ #include #include +#include #include #include @@ -24,12 +25,14 @@ enum dma_cache_op { DMA_UNMAP, DMA_MAP, }; +static bool hypercall_cflush = false; /* functions called by SWIOTLB */ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, size_t size, enum dma_data_direction dir, enum dma_cache_op op) { + struct gnttab_cache_flush cflush; unsigned long pfn; size_t left = size; @@ -39,7 +42,26 @@ static void dma_cache_maint(dma_addr_t handle, unsigned long offset, do { size_t len = left; - /* TODO: cache flush */ + /* buffers in highmem or foreign pages cannot cross page + * boundaries */ + if (len + offset > PAGE_SIZE) + len = PAGE_SIZE - offset; + + cflush.op = 0; + cflush.a.dev_bus_addr = pfn << PAGE_SHIFT; + cflush.offset = offset; + cflush.length = len; + + if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) + cflush.op = GNTTAB_CACHE_INVAL; + if (op == DMA_MAP) { + if (dir == DMA_FROM_DEVICE) + cflush.op = GNTTAB_CACHE_INVAL; + else + cflush.op = GNTTAB_CACHE_CLEAN; + } + if (cflush.op) + HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); offset = 0; pfn++; @@ -104,7 +126,7 @@ bool xen_arch_need_swiotlb(struct device *dev, unsigned long pfn, unsigned long mfn) { - return ((pfn != mfn) && !is_device_dma_coherent(dev)); + return (!hypercall_cflush && (pfn != mfn) && !is_device_dma_coherent(dev)); } int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, @@ -147,10 +169,18 @@ static struct dma_map_ops xen_swiotlb_dma_ops = { int __init xen_mm_init(void) { + struct gnttab_cache_flush cflush; if (!xen_initial_domain()) return 0; xen_swiotlb_init(1, false); xen_dma_ops = &xen_swiotlb_dma_ops; + + cflush.op = 0; + cflush.a.dev_bus_addr = 0; + cflush.offset = 0; + cflush.length = 0; + if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS) + hypercall_cflush = true; return 0; } arch_initcall(xen_mm_init); diff --git a/include/xen/interface/grant_table.h b/include/xen/interface/grant_table.h index e40fae9..bcce564 100644 --- a/include/xen/interface/grant_table.h +++ b/include/xen/interface/grant_table.h @@ -479,6 +479,25 @@ struct gnttab_get_version { DEFINE_GUEST_HANDLE_STRUCT(gnttab_get_version); /* + * Issue one or more cache maintenance operations on a portion of a + * page granted to the calling domain by a foreign domain. + */ +#define GNTTABOP_cache_flush 12 +struct gnttab_cache_flush { + union { + uint64_t dev_bus_addr; + grant_ref_t ref; + } a; + uint16_t offset; /* offset from start of grant */ + uint16_t length; /* size within the grant */ +#define GNTTAB_CACHE_CLEAN (1<<0) +#define GNTTAB_CACHE_INVAL (1<<1) +#define GNTTAB_CACHE_SOURCE_GREF (1<<31) + uint32_t op; +}; +DEFINE_GUEST_HANDLE_STRUCT(gnttab_cache_flush); + +/* * Bitfield values for update_pin_status.flags. */ /* Map the grant entry for access by I/O devices. */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/