Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759712AbZCMRBT (ORCPT ); Fri, 13 Mar 2009 13:01:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759421AbZCMRAg (ORCPT ); Fri, 13 Mar 2009 13:00:36 -0400 Received: from gw.goop.org ([64.81.55.164]:57366 "EHLO abulafia.goop.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758098AbZCMRAf (ORCPT ); Fri, 13 Mar 2009 13:00:35 -0400 From: Jeremy Fitzhardinge To: "H. Peter Anvin" Cc: the arch/x86 maintainers , Linux Kernel Mailing List , Xen-devel , David Airlie , Alex Nixon , Jeremy Fitzhardinge , Ian Campbell Subject: [PATCH 04/27] xen: Add xen_create_contiguous_region Date: Fri, 13 Mar 2009 09:59:49 -0700 Message-Id: <1236963612-14287-5-git-send-email-jeremy@goop.org> X-Mailer: git-send-email 1.6.0.6 In-Reply-To: <1236963612-14287-1-git-send-email-jeremy@goop.org> References: <1236963612-14287-1-git-send-email-jeremy@goop.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9543 Lines: 316 From: Alex Nixon A memory region must be physically contiguous in order to be accessed through DMA. This patch adds xen_create_contiguous_region, which ensures a region of contiguous virtual memory is also physically contiguous. Based on Stephen Tweedie's port of the 2.6.18-xen version. Remove contiguous_bitmap[] as it's no longer needed. Ported from linux-2.6.18-xen.hg 707:e410857fd83c Signed-off-by: Alex Nixon Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ian Campbell --- arch/x86/xen/mmu.c | 200 ++++++++++++++++++++++++++++++++++++++++ include/xen/interface/memory.h | 42 +++++++++ include/xen/xen-ops.h | 6 + 3 files changed, 248 insertions(+), 0 deletions(-) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index c2aa44b..b3eb2eb 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -51,6 +51,7 @@ #include #include #include +#include #include #include @@ -2097,6 +2098,205 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = { }; +/* Protected by xen_reservation_lock. */ +#define MAX_CONTIG_ORDER 9 /* 2MB */ +static unsigned long discontig_frames[1< MAX_CONTIG_ORDER)) + return -ENOMEM; + + memset((void *) vstart, 0, PAGE_SIZE << order); + + vm_unmap_aliases(); + + spin_lock_irqsave(&xen_reservation_lock, flags); + + /* 1. Zap current PTEs, remembering MFNs. */ + xen_zap_pfn_range(vstart, order, in_frames, NULL); + + /* 2. Get a new contiguous memory extent. */ + out_frame = virt_to_pfn(vstart); + success = xen_exchange_memory(1UL << order, 0, in_frames, + 1, order, &out_frame, + address_bits); + + /* 3. Map the new extent in place of old pages. */ + if (success) + xen_remap_exchanged_ptes(vstart, order, NULL, out_frame); + else + xen_remap_exchanged_ptes(vstart, order, in_frames, 0); + + spin_unlock_irqrestore(&xen_reservation_lock, flags); + + return success ? 0 : -ENOMEM; +} +EXPORT_SYMBOL_GPL(xen_create_contiguous_region); + +void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) +{ + unsigned long *out_frames = discontig_frames, in_frame; + unsigned long flags; + int success; + + if (xen_feature(XENFEAT_auto_translated_physmap)) + return; + + if (unlikely(order > MAX_CONTIG_ORDER)) + return; + + memset((void *) vstart, 0, PAGE_SIZE << order); + + vm_unmap_aliases(); + + spin_lock_irqsave(&xen_reservation_lock, flags); + + /* 1. Find start MFN of contiguous extent. */ + in_frame = virt_to_mfn(vstart); + + /* 2. Zap current PTEs. */ + xen_zap_pfn_range(vstart, order, NULL, out_frames); + + /* 3. Do the exchange for non-contiguous MFNs. */ + success = xen_exchange_memory(1, order, &in_frame, 1UL << order, + 0, out_frames, 0); + + /* 4. Map new pages in place of old pages. */ + if (success) + xen_remap_exchanged_ptes(vstart, order, out_frames, 0); + else + xen_remap_exchanged_ptes(vstart, order, NULL, in_frame); + + spin_unlock_irqrestore(&xen_reservation_lock, flags); +} +EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); + #ifdef CONFIG_XEN_DEBUG_FS static struct dentry *d_mmu_debug; diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h index 9df4bd0..63abbb2 100644 --- a/include/xen/interface/memory.h +++ b/include/xen/interface/memory.h @@ -55,6 +55,48 @@ struct xen_memory_reservation { DEFINE_GUEST_HANDLE_STRUCT(xen_memory_reservation); /* + * An atomic exchange of memory pages. If return code is zero then + * @out.extent_list provides GMFNs of the newly-allocated memory. + * Returns zero on complete success, otherwise a negative error code. + * On complete success then always @nr_exchanged == @in.nr_extents. + * On partial success @nr_exchanged indicates how much work was done. + */ +#define XENMEM_exchange 11 +struct xen_memory_exchange { + /* + * [IN] Details of memory extents to be exchanged (GMFN bases). + * Note that @in.address_bits is ignored and unused. + */ + struct xen_memory_reservation in; + + /* + * [IN/OUT] Details of new memory extents. + * We require that: + * 1. @in.domid == @out.domid + * 2. @in.nr_extents << @in.extent_order == + * @out.nr_extents << @out.extent_order + * 3. @in.extent_start and @out.extent_start lists must not overlap + * 4. @out.extent_start lists GPFN bases to be populated + * 5. @out.extent_start is overwritten with allocated GMFN bases + */ + struct xen_memory_reservation out; + + /* + * [OUT] Number of input extents that were successfully exchanged: + * 1. The first @nr_exchanged input extents were successfully + * deallocated. + * 2. The corresponding first entries in the output extent list correctly + * indicate the GMFNs that were successfully exchanged. + * 3. All other input and output extents are untouched. + * 4. If not all input exents are exchanged then the return code of this + * command will be non-zero. + * 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER! + */ + unsigned long nr_exchanged; +}; + +DEFINE_GUEST_HANDLE_STRUCT(xen_memory_exchange); +/* * Returns the maximum machine frame number of mapped RAM in this system. * This command always succeeds (it never returns an error code). * arg == NULL. diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 883a21b..d789c93 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -14,4 +14,10 @@ void xen_mm_unpin_all(void); void xen_timer_resume(void); void xen_arch_resume(void); +extern unsigned long *xen_contiguous_bitmap; +int xen_create_contiguous_region(unsigned long vstart, unsigned int order, + unsigned int address_bits); + +void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order); + #endif /* INCLUDE_XEN_OPS_H */ -- 1.6.0.6 -- 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/