Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756099Ab3I3PPF (ORCPT ); Mon, 30 Sep 2013 11:15:05 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:37220 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756080Ab3I3PPB (ORCPT ); Mon, 30 Sep 2013 11:15:01 -0400 Date: Mon, 30 Sep 2013 11:14:25 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ian.Campbell@citrix.com Subject: Re: [PATCH v6 06/19] xen/arm,arm64: enable SWIOTLB_XEN Message-ID: <20130930151425.GO3106@phenom.dumpdata.com> References: <1380298207-29151-6-git-send-email-stefano.stabellini@eu.citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1380298207-29151-6-git-send-email-stefano.stabellini@eu.citrix.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10076 Lines: 315 On Fri, Sep 27, 2013 at 05:09:54PM +0100, Stefano Stabellini wrote: > Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to > program the hardware with mfns rather than pfns for dma addresses. > Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select > SWIOTLB_XEN on arm and arm64. > > At the moment always rely on swiotlb-xen, but when Xen starts supporting > hardware IOMMUs we'll be able to avoid it conditionally on the presence > of an IOMMU on the platform. > > Implement xen_create_contiguous_region on arm and arm64 by using > XENMEM_exchange_and_pin. > > Initialize the xen-swiotlb from xen_early_init (before the native > dma_ops are initialized), set xen_dma_ops to &xen_swiotlb_dma_ops. > > Signed-off-by: Stefano Stabellini > > > Changes in v6: > - introduce and export xen_dma_ops; > - call xen_mm_init from as arch_initcall. > > Changes in v4: > - remove redefinition of DMA_ERROR_CODE; > - update the code to use XENMEM_exchange_and_pin and XENMEM_unpin; > - add a note about hardware IOMMU in the commit message. > > Changes in v3: > - code style changes; > - warn on XENMEM_put_dma_buf failures. > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/xen/hypervisor.h | 2 + > arch/arm/include/asm/xen/page.h | 2 + > arch/arm/xen/Makefile | 2 +- > arch/arm/xen/mm.c | 121 +++++++++++++++++++++++++++++++++ > arch/arm64/Kconfig | 1 + > arch/arm64/xen/Makefile | 2 +- > drivers/xen/Kconfig | 1 - > drivers/xen/swiotlb-xen.c | 16 +++++ > 9 files changed, 145 insertions(+), 3 deletions(-) > create mode 100644 arch/arm/xen/mm.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index c0bfb33..2c9d112 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -1848,6 +1848,7 @@ config XEN > depends on CPU_V7 && !CPU_V6 > depends on !GENERIC_ATOMIC64 > select ARM_PSCI > + select SWIOTLB_XEN > help > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. > > diff --git a/arch/arm/include/asm/xen/hypervisor.h b/arch/arm/include/asm/xen/hypervisor.h > index d7ab99a..1317ee4 100644 > --- a/arch/arm/include/asm/xen/hypervisor.h > +++ b/arch/arm/include/asm/xen/hypervisor.h > @@ -16,4 +16,6 @@ static inline enum paravirt_lazy_mode paravirt_get_lazy_mode(void) > return PARAVIRT_LAZY_NONE; > } > > +extern struct dma_map_ops *xen_dma_ops; > + > #endif /* _ASM_ARM_XEN_HYPERVISOR_H */ > diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h > index 359a7b5..b0f7150 100644 > --- a/arch/arm/include/asm/xen/page.h > +++ b/arch/arm/include/asm/xen/page.h > @@ -6,12 +6,14 @@ > > #include > #include > +#include > > #include > > #define pfn_to_mfn(pfn) (pfn) > #define phys_to_machine_mapping_valid(pfn) (1) > #define mfn_to_pfn(mfn) (mfn) > +#define mfn_to_local_pfn(m) (mfn_to_pfn(m)) > #define mfn_to_virt(m) (__va(mfn_to_pfn(m) << PAGE_SHIFT)) > > #define pte_mfn pte_pfn > diff --git a/arch/arm/xen/Makefile b/arch/arm/xen/Makefile > index 4384103..66fc35d 100644 > --- a/arch/arm/xen/Makefile > +++ b/arch/arm/xen/Makefile > @@ -1 +1 @@ > -obj-y := enlighten.o hypercall.o grant-table.o > +obj-y := enlighten.o hypercall.o grant-table.o mm.o > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c > new file mode 100644 > index 0000000..b065c98 > --- /dev/null > +++ b/arch/arm/xen/mm.c > @@ -0,0 +1,121 @@ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > +#include > + > +#include > +#include > +#include > +#include > + > +static int xen_exchange_memory(xen_ulong_t extents_in, > + unsigned int order_in, > + xen_pfn_t *pfns_in, > + xen_ulong_t extents_out, > + unsigned int order_out, > + xen_pfn_t *mfns_out, > + unsigned int address_bits) > +{ > + long rc; > + int success; > + > + struct xen_memory_exchange exchange = { > + .in = { > + .nr_extents = extents_in, > + .extent_order = order_in, > + .domid = DOMID_SELF > + }, > + .out = { > + .nr_extents = extents_out, > + .extent_order = order_out, > + .address_bits = address_bits, > + .domid = DOMID_SELF > + } I think you need to set .nr_exchange = 0 just in case there is garbage on the stack and the hypercall is -ENOSYS. > + }; > + set_xen_guest_handle(exchange.in.extent_start, pfns_in); > + set_xen_guest_handle(exchange.out.extent_start, mfns_out); > + > + BUG_ON(extents_in << order_in != extents_out << order_out); > + > + > + rc = HYPERVISOR_memory_op(XENMEM_exchange_and_pin, &exchange); > + success = (exchange.nr_exchanged == extents_in); > + > + BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0))); I think you need to set nr_exchange = 0 before you make the hypercall. Ohterwise you can get this: a). Say rc = -ENOSYS, in which case the exchage.nr_exchange won't be touched. success = 0 BUG(!0 && ( != 0)) <= BOOM. If the hypercall failed (say -EBUSY), so we have: success = 0 BUG(!0 && (1)) <= BOOM Which I thought would be more of a normal error - and we would just return the number of succesfull operations. > + BUG_ON(success && (rc != 0)); > + > + return success; > +} > + > +int xen_create_contiguous_region(unsigned long vstart, unsigned int order, > + unsigned int address_bits, > + dma_addr_t *dma_handle) > +{ > + phys_addr_t pstart = __pa(vstart); > + xen_pfn_t in_frame, out_frame; > + int success; > + > + /* Get a new contiguous memory extent. */ > + in_frame = out_frame = pstart >> PAGE_SHIFT; > + success = xen_exchange_memory(1, order, &in_frame, > + 1, order, &out_frame, > + address_bits); > + > + if (!success) > + return -ENOMEM; > + > + *dma_handle = out_frame << PAGE_SHIFT; > + > + return success ? 0 : -ENOMEM; > +} > +EXPORT_SYMBOL_GPL(xen_create_contiguous_region); > + > +void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) > +{ > + xen_pfn_t in_frame = __pa(vstart) >> PAGE_SHIFT; > + struct xen_unpin unpin = { > + .in = { > + .nr_extents = 1, > + .extent_order = order, > + .domid = DOMID_SELF > + }, > + }; > + set_xen_guest_handle(unpin.in.extent_start, &in_frame); > + > + WARN_ON(HYPERVISOR_memory_op(XENMEM_unpin, &unpin)); > +} > +EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); > + > +struct dma_map_ops *xen_dma_ops; > +EXPORT_SYMBOL_GPL(xen_dma_ops); > + > +static struct dma_map_ops xen_swiotlb_dma_ops = { > + .mapping_error = xen_swiotlb_dma_mapping_error, > + .alloc = xen_swiotlb_alloc_coherent, > + .free = xen_swiotlb_free_coherent, > + .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu, > + .sync_single_for_device = xen_swiotlb_sync_single_for_device, > + .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu, > + .sync_sg_for_device = xen_swiotlb_sync_sg_for_device, > + .map_sg = xen_swiotlb_map_sg_attrs, > + .unmap_sg = xen_swiotlb_unmap_sg_attrs, > + .map_page = xen_swiotlb_map_page, > + .unmap_page = xen_swiotlb_unmap_page, > + .dma_supported = xen_swiotlb_dma_supported, > +}; > + > +int __init xen_mm_init(void) > +{ > + xen_swiotlb_init(1, false); > + xen_dma_ops = &xen_swiotlb_dma_ops; > + return 0; > +} > +arch_initcall(xen_mm_init); > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 9737e97..aa1f6fb 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -209,6 +209,7 @@ config XEN_DOM0 > config XEN > bool "Xen guest support on ARM64 (EXPERIMENTAL)" > depends on ARM64 && OF > + select SWIOTLB_XEN > help > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64. > > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile > index be24040..0ef9637 100644 > --- a/arch/arm64/xen/Makefile > +++ b/arch/arm64/xen/Makefile > @@ -1,2 +1,2 @@ > -xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o) > +xen-arm-y += $(addprefix ../../arm/xen/, enlighten.o grant-table.o mm.o) > obj-y := xen-arm.o hypercall.o > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 9e02d60..7e83688 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -140,7 +140,6 @@ config XEN_GRANT_DEV_ALLOC > > config SWIOTLB_XEN > def_bool y > - depends on PCI && X86 > select SWIOTLB > > config XEN_TMEM > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > index 84aef43..a1cb0f4 100644 > --- a/drivers/xen/swiotlb-xen.c > +++ b/drivers/xen/swiotlb-xen.c > @@ -45,6 +45,8 @@ > #include > #include > #include > +#include > + > /* > * Used to do a quick range check in swiotlb_tbl_unmap_single and > * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this > @@ -58,6 +60,20 @@ static unsigned long xen_io_tlb_nslabs; > * Quick lookup value of the bus address of the IOTLB. > */ > > +#ifndef CONFIG_X86 > +static unsigned long dma_alloc_coherent_mask(struct device *dev, > + gfp_t gfp) > +{ > + unsigned long dma_mask = 0; > + > + dma_mask = dev->coherent_dma_mask; > + if (!dma_mask) > + dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32); > + > + return dma_mask; > +} > +#endif > + > struct xen_dma_info { > dma_addr_t dma_addr; > phys_addr_t phys_addr; > -- > 1.7.2.5 > -- 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/