From c0011dbfce69467b23b08fb4a64c39a409a935fb Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 4 Feb 2010 14:46:34 -0800 Subject: xen: use _PAGE_IOMAP in ioremap to do machine mappings In a Xen domain, ioremap operates on machine addresses, not pseudo-physical addresses. We use _PAGE_IOMAP to determine whether a mapping is intended for machine addresses. [ Impact: allow Xen domain to map real hardware ] Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Konrad Rzeszutek Wilk diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 018a0a4..bf5f7d3 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -112,13 +112,9 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine) */ static inline unsigned long mfn_to_local_pfn(unsigned long mfn) { - extern unsigned long max_mapnr; unsigned long pfn = mfn_to_pfn(mfn); - if ((pfn < max_mapnr) - && !xen_feature(XENFEAT_auto_translated_physmap) - && (get_phys_to_machine(pfn) != mfn)) - return max_mapnr; /* force !pfn_valid() */ - /* XXX fixme; not true with sparsemem */ + if (get_phys_to_machine(pfn) != mfn) + return -1; /* force !pfn_valid() */ return pfn; } diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 914f046..a4dea9d 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -56,9 +56,11 @@ #include #include +#include #include #include #include +#include #include #include "multicalls.h" @@ -377,6 +379,28 @@ static bool xen_page_pinned(void *ptr) return PagePinned(page); } +static bool xen_iomap_pte(pte_t pte) +{ + return xen_initial_domain() && (pte_flags(pte) & _PAGE_IOMAP); +} + +static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval) +{ + struct multicall_space mcs; + struct mmu_update *u; + + mcs = xen_mc_entry(sizeof(*u)); + u = mcs.args; + + /* ptep might be kmapped when using 32-bit HIGHPTE */ + u->ptr = arbitrary_virt_to_machine(ptep).maddr; + u->val = pte_val_ma(pteval); + + MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_IO); + + xen_mc_issue(PARAVIRT_LAZY_MMU); +} + static void xen_extend_mmu_update(const struct mmu_update *update) { struct multicall_space mcs; @@ -453,6 +477,11 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) void xen_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { + if (xen_iomap_pte(pteval)) { + xen_set_iomap_pte(ptep, pteval); + goto out; + } + ADD_STATS(set_pte_at, 1); // ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep)); ADD_STATS(set_pte_at_current, mm == current->mm); @@ -523,8 +552,25 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) return val; } +static pteval_t iomap_pte(pteval_t val) +{ + if (val & _PAGE_PRESENT) { + unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; + pteval_t flags = val & PTE_FLAGS_MASK; + + /* We assume the pte frame number is a MFN, so + just use it as-is. */ + val = ((pteval_t)pfn << PAGE_SHIFT) | flags; + } + + return val; +} + pteval_t xen_pte_val(pte_t pte) { + if (xen_initial_domain() && (pte.pte & _PAGE_IOMAP)) + return pte.pte; + return pte_mfn_to_pfn(pte.pte); } PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val); @@ -537,7 +583,11 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); pte_t xen_make_pte(pteval_t pte) { - pte = pte_pfn_to_mfn(pte); + if (unlikely(xen_initial_domain() && (pte & _PAGE_IOMAP))) + pte = iomap_pte(pte); + else + pte = pte_pfn_to_mfn(pte); + return native_make_pte(pte); } PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte); @@ -593,6 +643,11 @@ void xen_set_pud(pud_t *ptr, pud_t val) void xen_set_pte(pte_t *ptep, pte_t pte) { + if (xen_iomap_pte(pte)) { + xen_set_iomap_pte(ptep, pte); + return; + } + ADD_STATS(pte_update, 1); // ADD_STATS(pte_update_pinned, xen_page_pinned(ptep)); ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU); @@ -609,6 +664,11 @@ void xen_set_pte(pte_t *ptep, pte_t pte) #ifdef CONFIG_X86_PAE void xen_set_pte_atomic(pte_t *ptep, pte_t pte) { + if (xen_iomap_pte(pte)) { + xen_set_iomap_pte(ptep, pte); + return; + } + set_64bit((u64 *)ptep, native_pte_val(pte)); } @@ -1811,9 +1871,16 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) pte = pfn_pte(phys, prot); break; - default: + case FIX_PARAVIRT_BOOTMAP: + /* This is an MFN, but it isn't an IO mapping from the + IO domain */ pte = mfn_pte(phys, prot); break; + + default: + /* By default, set_fixmap is used for hardware mappings */ + pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP)); + break; } __native_set_fixmap(idx, pte); -- cgit v0.10.2 From 7347b4082e55ac4a673f06a0a0ce25c37273c9ec Mon Sep 17 00:00:00 2001 From: Alex Nixon Date: Fri, 19 Feb 2010 13:31:06 -0500 Subject: xen: Allow unprivileged Xen domains to create iomap pages PV DomU domains are allowed to map hardware MFNs for PCI passthrough, but are not generally allowed to map raw machine pages. In particular, various pieces of code try to map DMI and ACPI tables in the ISA ROM range. We disallow _PAGE_IOMAP for those mappings, so that they are redirected to a set of local zeroed pages we reserve for that purpose. [ Impact: prevent passthrough of ISA space, as we only allow PCI ] Signed-off-by: Alex Nixon Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Konrad Rzeszutek Wilk diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 65d8d79..3254e8b 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1145,6 +1145,10 @@ asmlinkage void __init xen_start_kernel(void) pgd = (pgd_t *)xen_start_info->pt_base; + if (!xen_initial_domain()) + __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); + + __supported_pte_mask |= _PAGE_IOMAP; /* Don't do the full vcpu_info placement stuff until we have a possible map and a non-dummy shared_info. */ per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index a4dea9d..a5577f5 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -51,6 +51,7 @@ #include #include #include +#include #include #include @@ -381,7 +382,7 @@ static bool xen_page_pinned(void *ptr) static bool xen_iomap_pte(pte_t pte) { - return xen_initial_domain() && (pte_flags(pte) & _PAGE_IOMAP); + return pte_flags(pte) & _PAGE_IOMAP; } static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval) @@ -583,10 +584,21 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); pte_t xen_make_pte(pteval_t pte) { - if (unlikely(xen_initial_domain() && (pte & _PAGE_IOMAP))) + phys_addr_t addr = (pte & PTE_PFN_MASK); + + /* + * Unprivileged domains are allowed to do IOMAPpings for + * PCI passthrough, but not map ISA space. The ISA + * mappings are just dummy local mappings to keep other + * parts of the kernel happy. + */ + if (unlikely(pte & _PAGE_IOMAP) && + (xen_initial_domain() || addr >= ISA_END_ADDRESS)) { pte = iomap_pte(pte); - else + } else { + pte &= ~_PAGE_IOMAP; pte = pte_pfn_to_mfn(pte); + } return native_make_pte(pte); } -- cgit v0.10.2 From 19001c8c5bfa032ed45b10dfe48e355f5df88c61 Mon Sep 17 00:00:00 2001 From: Alex Nixon Date: Mon, 9 Feb 2009 12:05:46 -0800 Subject: xen: Rename the balloon lock * xen_create_contiguous_region needs access to the balloon lock to ensure memory doesn't change under its feet, so expose the balloon lock * Change the name of the lock to xen_reservation_lock, to imply it's now less-specific usage. [ Impact: cleanup ] Signed-off-by: Alex Nixon Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Konrad Rzeszutek Wilk diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index a5577f5..9e0d82f 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -70,6 +70,13 @@ #define MMU_UPDATE_HISTO 30 +/* + * Protects atomic reservation decrease/increase against concurrent increases. + * Also protects non-atomic updates of current_pages and driver_pages, and + * balloon lists. + */ +DEFINE_SPINLOCK(xen_reservation_lock); + #ifdef CONFIG_XEN_DEBUG_FS static struct { diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 1a0d8c2..500290b 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -85,13 +85,6 @@ static struct sys_device balloon_sysdev; static int register_balloon(struct sys_device *sysdev); -/* - * Protects atomic reservation decrease/increase against concurrent increases. - * Also protects non-atomic updates of current_pages and driver_pages, and - * balloon lists. - */ -static DEFINE_SPINLOCK(balloon_lock); - static struct balloon_stats balloon_stats; /* We increase/decrease in batches which fit in a page */ @@ -210,7 +203,7 @@ static int increase_reservation(unsigned long nr_pages) if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); - spin_lock_irqsave(&balloon_lock, flags); + spin_lock_irqsave(&xen_reservation_lock, flags); page = balloon_first_page(); for (i = 0; i < nr_pages; i++) { @@ -254,7 +247,7 @@ static int increase_reservation(unsigned long nr_pages) balloon_stats.current_pages += rc; out: - spin_unlock_irqrestore(&balloon_lock, flags); + spin_unlock_irqrestore(&xen_reservation_lock, flags); return rc < 0 ? rc : rc != nr_pages; } @@ -299,7 +292,7 @@ static int decrease_reservation(unsigned long nr_pages) kmap_flush_unused(); flush_tlb_all(); - spin_lock_irqsave(&balloon_lock, flags); + spin_lock_irqsave(&xen_reservation_lock, flags); /* No more mappings: invalidate P2M and add to balloon. */ for (i = 0; i < nr_pages; i++) { @@ -315,7 +308,7 @@ static int decrease_reservation(unsigned long nr_pages) balloon_stats.current_pages -= nr_pages; - spin_unlock_irqrestore(&balloon_lock, flags); + spin_unlock_irqrestore(&xen_reservation_lock, flags); return need_sleep; } diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h index af36ead..e6adce6 100644 --- a/include/xen/interface/memory.h +++ b/include/xen/interface/memory.h @@ -9,6 +9,8 @@ #ifndef __XEN_PUBLIC_MEMORY_H__ #define __XEN_PUBLIC_MEMORY_H__ +#include + /* * Increase or decrease the specified domain's memory reservation. Returns a * -ve errcode on failure, or the # extents successfully allocated or freed. @@ -142,4 +144,10 @@ struct xen_translate_gpfn_list { }; DEFINE_GUEST_HANDLE_STRUCT(xen_translate_gpfn_list); + +/* + * Prevent the balloon driver from changing the memory reservation + * during a driver critical region. + */ +extern spinlock_t xen_reservation_lock; #endif /* __XEN_PUBLIC_MEMORY_H__ */ -- cgit v0.10.2 From 08bbc9da92f7e44b9c208c6a1adba70c403b255e Mon Sep 17 00:00:00 2001 From: Alex Nixon Date: Mon, 9 Feb 2009 12:05:46 -0800 Subject: xen: Add xen_create_contiguous_region 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 [ Impact: add Xen-internal API to make pages phys-contig ] Signed-off-by: Alex Nixon Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ian Campbell Signed-off-by: Konrad Rzeszutek Wilk diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9e0d82f..eb51402 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -53,6 +53,7 @@ #include #include #include +#include #include #include @@ -2027,6 +2028,206 @@ void __init xen_init_mmu_ops(void) pv_mmu_ops = xen_mmu_ops; } +/* 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 e6adce6..d3938d3 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 */ -- cgit v0.10.2 From a0d40c80256e31b23849f2ba781b74bf0218a1fa Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Fri, 26 Mar 2010 15:28:51 -0700 Subject: vmap: add flag to allow lazy unmap to be disabled at runtime Add a flag to force lazy_max_pages() to zero to prevent any outstanding mapped pages. We'll need this for Xen. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Nick Piggin diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 227c2a5..b840fda 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -7,6 +7,8 @@ struct vm_area_struct; /* vma defining user mapping in mm_types.h */ +extern bool vmap_lazy_unmap; + /* bits in flags of vmalloc's vm_struct below */ #define VM_IOREMAP 0x00000001 /* ioremap() and friends */ #define VM_ALLOC 0x00000002 /* vmalloc() */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ae00746..7f35fe2 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -31,6 +31,7 @@ #include #include +bool vmap_lazy_unmap __read_mostly = true; /*** Page table manipulation functions ***/ @@ -502,6 +503,9 @@ static unsigned long lazy_max_pages(void) { unsigned int log; + if (!vmap_lazy_unmap) + return 0; + log = fls(num_online_cpus()); return log * (32UL * 1024 * 1024 / PAGE_SIZE); -- cgit v0.10.2 From d2cb214551de8180542a04ec8c86c0c9412c5124 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Fri, 26 Mar 2010 15:37:50 -0700 Subject: xen/mmu: inhibit vmap aliases rather than trying to clear them out Rather than trying to deal with aliases once they appear, just completely inhibit them. Mostly the removal of aliases was managable, but it comes unstuck in xen_create_contiguous_region() because it gets executed at interrupt time (as a result of dma_alloc_coherent()), which causes all sorts of confusion in the vmap code, as it was never intended to be run in interrupt context. This has the unfortunate side effect of removing all the unmap batching the vmap code so carefully added, but that can't be helped. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Konrad Rzeszutek Wilk diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index eb51402..ef5728d 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include @@ -1015,8 +1016,6 @@ static int xen_pin_page(struct mm_struct *mm, struct page *page, read-only, and can be pinned. */ static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd) { - vm_unmap_aliases(); - xen_mc_batch(); if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) { @@ -1580,7 +1579,6 @@ static void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, unsigned l if (PagePinned(virt_to_page(mm->pgd))) { SetPagePinned(page); - vm_unmap_aliases(); if (!PageHighMem(page)) { make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn))); if (level == PT_PTE && USE_SPLIT_PTLOCKS) @@ -2026,6 +2024,8 @@ void __init xen_init_mmu_ops(void) x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start; x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done; pv_mmu_ops = xen_mmu_ops; + + vmap_lazy_unmap = false; } /* Protected by xen_reservation_lock. */ @@ -2165,8 +2165,6 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order, memset((void *) vstart, 0, PAGE_SIZE << order); - vm_unmap_aliases(); - spin_lock_irqsave(&xen_reservation_lock, flags); /* 1. Zap current PTEs, remembering MFNs. */ @@ -2204,8 +2202,6 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) memset((void *) vstart, 0, PAGE_SIZE << order); - vm_unmap_aliases(); - spin_lock_irqsave(&xen_reservation_lock, flags); /* 1. Find start MFN of contiguous extent. */ -- cgit v0.10.2 From b097186fd29d5bc5a26d1ae87995821ffc27b66e Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 11 May 2010 10:05:49 -0400 Subject: swiotlb-xen: SWIOTLB library for Xen PV guest with PCI passthrough. This patchset: PV guests under Xen are running in an non-contiguous memory architecture. When PCI pass-through is utilized, this necessitates an IOMMU for translating bus (DMA) to virtual and vice-versa and also providing a mechanism to have contiguous pages for device drivers operations (say DMA operations). Specifically, under Xen the Linux idea of pages is an illusion. It assumes that pages start at zero and go up to the available memory. To help with that, the Linux Xen MMU provides a lookup mechanism to translate the page frame numbers (PFN) to machine frame numbers (MFN) and vice-versa. The MFN are the "real" frame numbers. Furthermore memory is not contiguous. Xen hypervisor stitches memory for guests from different pools, which means there is no guarantee that PFN==MFN and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are allocated in descending order (high to low), meaning the guest might never get any MFN's under the 4GB mark. Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Jeremy Fitzhardinge Cc: FUJITA Tomonori Cc: Albert Herranz Cc: Ian Campbell diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index fad3df2..97199c2 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -62,4 +62,8 @@ config XEN_SYS_HYPERVISOR virtual environment, /sys/hypervisor will still be present, but will have no xen contents. +config SWIOTLB_XEN + def_bool y + depends on SWIOTLB + endmenu diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile index 7c28434..85f84cf 100644 --- a/drivers/xen/Makefile +++ b/drivers/xen/Makefile @@ -9,4 +9,5 @@ obj-$(CONFIG_XEN_XENCOMM) += xencomm.o obj-$(CONFIG_XEN_BALLOON) += balloon.o obj-$(CONFIG_XEN_DEV_EVTCHN) += evtchn.o obj-$(CONFIG_XENFS) += xenfs/ -obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o \ No newline at end of file +obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o +obj-$(CONFIG_SWIOTLB_XEN) += swiotlb-xen.o diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c new file mode 100644 index 0000000..54469c3 --- /dev/null +++ b/drivers/xen/swiotlb-xen.c @@ -0,0 +1,515 @@ +/* + * Copyright 2010 + * by Konrad Rzeszutek Wilk + * + * This code provides a IOMMU for Xen PV guests with PCI passthrough. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License v2.0 as published by + * the Free Software Foundation + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * PV guests under Xen are running in an non-contiguous memory architecture. + * + * When PCI pass-through is utilized, this necessitates an IOMMU for + * translating bus (DMA) to virtual and vice-versa and also providing a + * mechanism to have contiguous pages for device drivers operations (say DMA + * operations). + * + * Specifically, under Xen the Linux idea of pages is an illusion. It + * assumes that pages start at zero and go up to the available memory. To + * help with that, the Linux Xen MMU provides a lookup mechanism to + * translate the page frame numbers (PFN) to machine frame numbers (MFN) + * and vice-versa. The MFN are the "real" frame numbers. Furthermore + * memory is not contiguous. Xen hypervisor stitches memory for guests + * from different pools, which means there is no guarantee that PFN==MFN + * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are + * allocated in descending order (high to low), meaning the guest might + * never get any MFN's under the 4GB mark. + * + */ + +#include +#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 + * API. + */ + +static char *xen_io_tlb_start, *xen_io_tlb_end; +static unsigned long xen_io_tlb_nslabs; +/* + * Quick lookup value of the bus address of the IOTLB. + */ + +u64 start_dma_addr; + +static dma_addr_t xen_phys_to_bus(phys_addr_t paddr) +{ + return phys_to_machine(XPADDR(paddr)).maddr;; +} + +static phys_addr_t xen_bus_to_phys(dma_addr_t baddr) +{ + return machine_to_phys(XMADDR(baddr)).paddr; +} + +static dma_addr_t xen_virt_to_bus(void *address) +{ + return xen_phys_to_bus(virt_to_phys(address)); +} + +static int check_pages_physically_contiguous(unsigned long pfn, + unsigned int offset, + size_t length) +{ + unsigned long next_mfn; + int i; + int nr_pages; + + next_mfn = pfn_to_mfn(pfn); + nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT; + + for (i = 1; i < nr_pages; i++) { + if (pfn_to_mfn(++pfn) != ++next_mfn) + return 0; + } + return 1; +} + +static int range_straddles_page_boundary(phys_addr_t p, size_t size) +{ + unsigned long pfn = PFN_DOWN(p); + unsigned int offset = p & ~PAGE_MASK; + + if (offset + size <= PAGE_SIZE) + return 0; + if (check_pages_physically_contiguous(pfn, offset, size)) + return 0; + return 1; +} + +static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) +{ + unsigned long mfn = PFN_DOWN(dma_addr); + unsigned long pfn = mfn_to_local_pfn(mfn); + phys_addr_t paddr; + + /* If the address is outside our domain, it CAN + * have the same virtual address as another address + * in our domain. Therefore _only_ check address within our domain. + */ + if (pfn_valid(pfn)) { + paddr = PFN_PHYS(pfn); + return paddr >= virt_to_phys(xen_io_tlb_start) && + paddr < virt_to_phys(xen_io_tlb_end); + } + return 0; +} + +static int max_dma_bits = 32; + +static int +xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs) +{ + int i, rc; + int dma_bits; + + dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT; + + i = 0; + do { + int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE); + + do { + rc = xen_create_contiguous_region( + (unsigned long)buf + (i << IO_TLB_SHIFT), + get_order(slabs << IO_TLB_SHIFT), + dma_bits); + } while (rc && dma_bits++ < max_dma_bits); + if (rc) + return rc; + + i += slabs; + } while (i < nslabs); + return 0; +} + +void __init xen_swiotlb_init(int verbose) +{ + unsigned long bytes; + int rc; + + xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT); + xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE); + + bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT; + + /* + * Get IO TLB memory from any location. + */ + xen_io_tlb_start = alloc_bootmem(bytes); + if (!xen_io_tlb_start) + panic("Cannot allocate SWIOTLB buffer"); + + xen_io_tlb_end = xen_io_tlb_start + bytes; + /* + * And replace that memory with pages under 4GB. + */ + rc = xen_swiotlb_fixup(xen_io_tlb_start, + bytes, + xen_io_tlb_nslabs); + if (rc) + goto error; + + start_dma_addr = xen_virt_to_bus(xen_io_tlb_start); + swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose); + + return; +error: + panic("DMA(%d): Failed to exchange pages allocated for DMA with Xen! "\ + "We either don't have the permission or you do not have enough"\ + "free memory under 4GB!\n", rc); +} + +void * +xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, + dma_addr_t *dma_handle, gfp_t flags) +{ + void *ret; + int order = get_order(size); + u64 dma_mask = DMA_BIT_MASK(32); + unsigned long vstart; + + /* + * Ignore region specifiers - the kernel's ideas of + * pseudo-phys memory layout has nothing to do with the + * machine physical layout. We can't allocate highmem + * because we can't return a pointer to it. + */ + flags &= ~(__GFP_DMA | __GFP_HIGHMEM); + + if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret)) + return ret; + + vstart = __get_free_pages(flags, order); + ret = (void *)vstart; + + if (hwdev && hwdev->coherent_dma_mask) + dma_mask = dma_alloc_coherent_mask(hwdev, flags); + + if (ret) { + if (xen_create_contiguous_region(vstart, order, + fls64(dma_mask)) != 0) { + free_pages(vstart, order); + return NULL; + } + memset(ret, 0, size); + *dma_handle = virt_to_machine(ret).maddr; + } + return ret; +} +EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent); + +void +xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, + dma_addr_t dev_addr) +{ + int order = get_order(size); + + if (dma_release_from_coherent(hwdev, order, vaddr)) + return; + + xen_destroy_contiguous_region((unsigned long)vaddr, order); + free_pages((unsigned long)vaddr, order); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent); + + +/* + * Map a single buffer of the indicated size for DMA in streaming mode. The + * physical address to use is returned. + * + * Once the device is given the dma address, the device owns this memory until + * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed. + */ +dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + phys_addr_t phys = page_to_phys(page) + offset; + dma_addr_t dev_addr = xen_phys_to_bus(phys); + void *map; + + BUG_ON(dir == DMA_NONE); + /* + * If the address happens to be in the device's DMA window, + * we can safely return the device addr and not worry about bounce + * buffering it. + */ + if (dma_capable(dev, dev_addr, size) && + !range_straddles_page_boundary(phys, size) && !swiotlb_force) + return dev_addr; + + /* + * Oh well, have to allocate and map a bounce buffer. + */ + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); + if (!map) + return DMA_ERROR_CODE; + + dev_addr = xen_virt_to_bus(map); + + /* + * Ensure that the address returned is DMA'ble + */ + if (!dma_capable(dev, dev_addr, size)) + panic("map_single: bounce buffer is not DMA'ble"); + + return dev_addr; +} +EXPORT_SYMBOL_GPL(xen_swiotlb_map_page); + +/* + * Unmap a single streaming mode DMA translation. The dma_addr and size must + * match what was provided for in a previous xen_swiotlb_map_page call. All + * other usages are undefined. + * + * After this call, reads by the cpu to the buffer are guaranteed to see + * whatever the device wrote there. + */ +static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir) +{ + phys_addr_t paddr = xen_bus_to_phys(dev_addr); + + BUG_ON(dir == DMA_NONE); + + /* NOTE: We use dev_addr here, not paddr! */ + if (is_xen_swiotlb_buffer(dev_addr)) { + swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir); + return; + } + + if (dir != DMA_FROM_DEVICE) + return; + + /* + * phys_to_virt doesn't work with hihgmem page but we could + * call dma_mark_clean() with hihgmem page here. However, we + * are fine since dma_mark_clean() is null on POWERPC. We can + * make dma_mark_clean() take a physical address if necessary. + */ + dma_mark_clean(phys_to_virt(paddr), size); +} + +void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + xen_unmap_single(hwdev, dev_addr, size, dir); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page); + +/* + * Make physical memory consistent for a single streaming mode DMA translation + * after a transfer. + * + * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer + * using the cpu, yet do not wish to teardown the dma mapping, you must + * call this function before doing so. At the next point you give the dma + * address back to the card, you must first perform a + * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer + */ +static void +xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + enum dma_sync_target target) +{ + phys_addr_t paddr = xen_bus_to_phys(dev_addr); + + BUG_ON(dir == DMA_NONE); + + /* NOTE: We use dev_addr here, not paddr! */ + if (is_xen_swiotlb_buffer(dev_addr)) { + swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir, + target); + return; + } + + if (dir != DMA_FROM_DEVICE) + return; + + dma_mark_clean(phys_to_virt(paddr), size); +} + +void +xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir) +{ + xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu); + +void +xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir) +{ + xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device); + +/* + * Map a set of buffers described by scatterlist in streaming mode for DMA. + * This is the scatter-gather version of the above xen_swiotlb_map_page + * interface. Here the scatter gather list elements are each tagged with the + * appropriate dma address and length. They are obtained via + * sg_dma_{address,length}(SG). + * + * NOTE: An implementation may be able to use a smaller number of + * DMA address/length pairs than there are SG table elements. + * (for example via virtual mapping capabilities) + * The routine returns the number of addr/length pairs actually + * used, at most nents. + * + * Device ownership issues as mentioned above for xen_swiotlb_map_page are the + * same here. + */ +int +xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + struct scatterlist *sg; + int i; + + BUG_ON(dir == DMA_NONE); + + for_each_sg(sgl, sg, nelems, i) { + phys_addr_t paddr = sg_phys(sg); + dma_addr_t dev_addr = xen_phys_to_bus(paddr); + + if (swiotlb_force || + !dma_capable(hwdev, dev_addr, sg->length) || + range_straddles_page_boundary(paddr, sg->length)) { + void *map = swiotlb_tbl_map_single(hwdev, + start_dma_addr, + sg_phys(sg), + sg->length, dir); + if (!map) { + /* Don't panic here, we expect map_sg users + to do proper error handling. */ + xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, + attrs); + sgl[0].dma_length = 0; + return DMA_ERROR_CODE; + } + sg->dma_address = xen_virt_to_bus(map); + } else + sg->dma_address = dev_addr; + sg->dma_length = sg->length; + } + return nelems; +} +EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs); + +int +xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems, + enum dma_data_direction dir) +{ + return xen_swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg); + +/* + * Unmap a set of streaming mode DMA translations. Again, cpu read rules + * concerning calls here are the same as for swiotlb_unmap_page() above. + */ +void +xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + struct scatterlist *sg; + int i; + + BUG_ON(dir == DMA_NONE); + + for_each_sg(sgl, sg, nelems, i) + xen_unmap_single(hwdev, sg->dma_address, sg->dma_length, dir); + +} +EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs); + +void +xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems, + enum dma_data_direction dir) +{ + return xen_swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg); + +/* + * Make physical memory consistent for a set of streaming mode DMA translations + * after a transfer. + * + * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules + * and usage. + */ +static void +xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + enum dma_sync_target target) +{ + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nelems, i) + xen_swiotlb_sync_single(hwdev, sg->dma_address, + sg->dma_length, dir, target); +} + +void +xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir) +{ + xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu); + +void +xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir) +{ + xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device); + +int +xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr) +{ + return !dma_addr; +} +EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error); + +/* + * Return whether the given device DMA address mask can be supported + * properly. For example, if your device can only drive the low 24-bits + * during bus mastering, then you would pass 0x00ffffff as the mask to + * this function. + */ +int +xen_swiotlb_dma_supported(struct device *hwdev, u64 mask) +{ + return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask; +} +EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported); diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h new file mode 100644 index 0000000..2ea2fdc --- /dev/null +++ b/include/xen/swiotlb-xen.h @@ -0,0 +1,65 @@ +#ifndef __LINUX_SWIOTLB_XEN_H +#define __LINUX_SWIOTLB_XEN_H + +#include + +extern void xen_swiotlb_init(int verbose); + +extern void +*xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, + dma_addr_t *dma_handle, gfp_t flags); + +extern void +xen_swiotlb_free_coherent(struct device *hwdev, size_t size, + void *vaddr, dma_addr_t dma_handle); + +extern dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + struct dma_attrs *attrs); + +extern void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + struct dma_attrs *attrs); +/* +extern int +xen_swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents, + enum dma_data_direction dir); + +extern void +xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents, + enum dma_data_direction dir); +*/ +extern int +xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + struct dma_attrs *attrs); + +extern void +xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + struct dma_attrs *attrs); + +extern void +xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir); + +extern void +xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir); + +extern void +xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir); + +extern void +xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir); + +extern int +xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr); + +extern int +xen_swiotlb_dma_supported(struct device *hwdev, u64 mask); + +#endif /* __LINUX_SWIOTLB_XEN_H */ -- cgit v0.10.2 From bbbe57386e857eb2a8d4abcae71063c819c06ff1 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 9 Feb 2010 14:30:55 -0500 Subject: pci-swiotlb-xen: Add glue code to setup dma_ops utilizing xen_swiotlb_* functions. We add the glue code that sets up a dma_ops structure with the xen_swiotlb_* functions. The code turns on xen_swiotlb flag when it detects it is running under Xen and it is either in privileged mode or the iommu=soft flag was passed in. It also disables the bare-metal SWIOTLB if the Xen-SWIOTLB has been enabled. Note: The Xen-SWIOTLB is only built when CONFIG_XEN is enabled. Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Jeremy Fitzhardinge Cc: FUJITA Tomonori Cc: Albert Herranz Cc: Ian Campbell diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h new file mode 100644 index 0000000..1be1ab7 --- /dev/null +++ b/arch/x86/include/asm/xen/swiotlb-xen.h @@ -0,0 +1,14 @@ +#ifndef _ASM_X86_SWIOTLB_XEN_H +#define _ASM_X86_SWIOTLB_XEN_H + +#ifdef CONFIG_SWIOTLB_XEN +extern int xen_swiotlb; +extern int __init pci_xen_swiotlb_detect(void); +extern void __init pci_xen_swiotlb_init(void); +#else +#define xen_swiotlb (0) +static inline int __init pci_xen_swiotlb_detect(void) { return 0; } +static inline void __init pci_xen_swiotlb_init(void) { } +#endif + +#endif /* _ASM_X86_SWIOTLB_XEN_H */ diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index 3bb4fc2..32af238 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile @@ -18,3 +18,4 @@ obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o +obj-$(CONFIG_SWIOTLB_XEN) += pci-swiotlb-xen.o diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c new file mode 100644 index 0000000..a013ec9 --- /dev/null +++ b/arch/x86/xen/pci-swiotlb-xen.c @@ -0,0 +1,58 @@ +/* Glue code to lib/swiotlb-xen.c */ + +#include +#include + +#include +#include + +int xen_swiotlb __read_mostly; + +static struct dma_map_ops xen_swiotlb_dma_ops = { + .mapping_error = xen_swiotlb_dma_mapping_error, + .alloc_coherent = xen_swiotlb_alloc_coherent, + .free_coherent = 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, +}; + +/* + * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary + * + * This returns non-zero if we are forced to use xen_swiotlb (by the boot + * option). + */ +int __init pci_xen_swiotlb_detect(void) +{ + + /* If running as PV guest, either iommu=soft, or swiotlb=force will + * activate this IOMMU. If running as PV privileged, activate it + * irregardlesss. + */ + if ((xen_initial_domain() || swiotlb || swiotlb_force) && + (xen_pv_domain())) + xen_swiotlb = 1; + + /* If we are running under Xen, we MUST disable the native SWIOTLB. + * Don't worry about swiotlb_force flag activating the native, as + * the 'swiotlb' flag is the only one turning it on. */ + if (xen_pv_domain()) + swiotlb = 0; + + return xen_swiotlb; +} + +void __init pci_xen_swiotlb_init(void) +{ + if (xen_swiotlb) { + xen_swiotlb_init(1); + dma_ops = &xen_swiotlb_dma_ops; + } +} -- cgit v0.10.2 From fe96eb404e33b59bb39f7050205f7c56c1c7d686 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Thu, 18 Mar 2010 13:53:24 -0400 Subject: x86: Detect whether we should use Xen SWIOTLB. It is paramount that we call pci_xen_swiotlb_detect before pci_swiotlb_detect as both implementations use the 'swiotlb' and 'swiotlb_force' flags. The pci-xen_swiotlb_detect inhibits the swiotlb_force and swiotlb flag so that the native SWIOTLB implementation is not enabled when running under Xen. [since v1 changed two Cc's to Acked-by] Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Jeremy Fitzhardinge Acked-by: FUJITA Tomonori [http://lkml.org/lkml/2010/7/27/374] Cc: Albert Herranz Cc: Ian Campbell Cc: Thomas Gleixner Acked-by: "H. Peter Anvin" [conditional http://lkml.org/lkml/2010/8/2/324] Cc: x86@kernel.org Cc: Jesse Barnes diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 4b7e3d8..9f07cfc 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -13,6 +13,7 @@ #include #include #include +#include static int forbid_dac __read_mostly; @@ -132,7 +133,7 @@ void __init pci_iommu_alloc(void) /* free the range so iommu could get some range less than 4G */ dma32_free_bootmem(); - if (pci_swiotlb_detect()) + if (pci_xen_swiotlb_detect() || pci_swiotlb_detect()) goto out; gart_iommu_hole_init(); @@ -144,6 +145,8 @@ void __init pci_iommu_alloc(void) /* needs to be called after gart_iommu_hole_init */ amd_iommu_detect(); out: + pci_xen_swiotlb_init(); + pci_swiotlb_init(); } @@ -296,7 +299,7 @@ static int __init pci_iommu_init(void) #endif x86_init.iommu.iommu_init(); - if (swiotlb) { + if (swiotlb || xen_swiotlb) { printk(KERN_INFO "PCI-DMA: " "Using software bounce buffering for IO (SWIOTLB)\n"); swiotlb_print_info(); -- cgit v0.10.2