|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v9] xen/grant-table: Avoid m2p_override during mapping
The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the original functions were renamed to __gnttab_[un]map_refs, with a new parameter m2p_override - arch specific functions *_foreign_p2m_mapping do everything after the hypercall - it cuts out common parts from m2p_*_override functions to *_foreign_p2m_mapping functions - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with m2p_override false - a new function gnttab_[un]map_refs_userspace provides the old behaviour It also removes a stray space from page.h and change ret to 0 if XENFEAT_auto_translated_physmap, as that is the only possible return value there. Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx> Original-by: Anthony Liguori <aliguori@xxxxxxxxxx> --- v2: - move the storing of the old mfn in page->index to gnttab_map_refs - move the function header update to a separate patch v3: - a new approach to retain old behaviour where it needed - squash the patches into one v4: - move out the common bits from m2p* functions, and pass pfn/mfn as parameter - clear page->private before doing anything with the page, so m2p_find_override won't race with this v5: - change return value handling in __gnttab_[un]map_refs - remove a stray space in page.h - add detail why ret = 0 now at some places v6: - don't pass pfn to m2p* functions, just get it locally v7: - the previous version broke build on ARM, as there is no need for those p2m changes. I've put them into arch specific functions, which are stubs on arm v8: - give credit to Anthony Liguori who submitted a very similar patch originally: http://marc.info/?i=1384307336-5328-1-git-send-email-anthony%40codemonkey.ws - create ARM stub for get_phys_to_machine - move definition of mfn in __gnttab_unmap_refs to the right place v9: - move everything after the hypercalls into set/clear_foreign_p2m_mapping - m2p override functions became unnecessary on ARM therefore arch/arm/include/asm/xen/page.h | 19 +++--- arch/arm/xen/p2m.c | 34 ++++++++++ arch/x86/include/asm/xen/page.h | 13 +++- arch/x86/xen/p2m.c | 127 ++++++++++++++++++++++++++++++----- drivers/block/xen-blkback/blkback.c | 15 ++--- drivers/xen/gntdev.c | 13 ++-- drivers/xen/grant-table.c | 115 +++++++++++-------------------- include/xen/grant_table.h | 8 ++- 8 files changed, 227 insertions(+), 117 deletions(-) diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index e0965ab..4eaeb3f 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -97,16 +97,15 @@ static inline pte_t *lookup_address(unsigned long address, unsigned int *level) return NULL; } -static inline int m2p_add_override(unsigned long mfn, struct page *page, - struct gnttab_map_grant_ref *kmap_op) -{ - return 0; -} - -static inline int m2p_remove_override(struct page *page, bool clear_pte) -{ - return 0; -} +extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override); + +extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override); bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn); bool __set_phys_to_machine_multi(unsigned long pfn, unsigned long mfn, diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c index b31ee1b2..74d977c 100644 --- a/arch/arm/xen/p2m.c +++ b/arch/arm/xen/p2m.c @@ -146,6 +146,40 @@ unsigned long __mfn_to_pfn(unsigned long mfn) } EXPORT_SYMBOL_GPL(__mfn_to_pfn); +int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) +{ + int i; + + for (i = 0; i < count; i++) { + if (map_ops[i].status) + continue; + set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT, + map_ops[i].dev_bus_addr >> PAGE_SHIFT); + } + + return 0; +} +EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); + +int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) +{ + int i; + + for (i = 0; i < count; i++) { + set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT, + INVALID_P2M_ENTRY); + } + + return 0; +} +EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); + bool __set_phys_to_machine_multi(unsigned long pfn, unsigned long mfn, unsigned long nr_pages) { diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 3e276eb..9edc8a8 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -49,10 +49,19 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn); extern unsigned long set_phys_range_identity(unsigned long pfn_s, unsigned long pfn_e); +extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override); extern int m2p_add_override(unsigned long mfn, struct page *page, struct gnttab_map_grant_ref *kmap_op); +extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override); extern int m2p_remove_override(struct page *page, - struct gnttab_map_grant_ref *kmap_op); + struct gnttab_map_grant_ref *kmap_op, + unsigned long mfn); extern struct page *m2p_find_override(unsigned long mfn); extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); @@ -121,7 +130,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) pfn = m2p_find_override_pfn(mfn, ~0); } - /* + /* * pfn is ~0 if there are no entries in the m2p for mfn or if the * entry doesn't map back to the mfn and m2p_override doesn't have a * valid entry for it. diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 696c694..305af27 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -881,6 +881,67 @@ static unsigned long mfn_hash(unsigned long mfn) return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); } +int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) +{ + int i, ret = 0; + bool lazy = false; + pte_t *pte; + + if (xen_feature(XENFEAT_auto_translated_physmap)) + return 0; + + if (m2p_override && + !in_interrupt() && + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { + arch_enter_lazy_mmu_mode(); + lazy = true; + } + + for (i = 0; i < count; i++) { + unsigned long mfn, pfn; + + /* Do not add to override if the map failed. */ + if (map_ops[i].status) + continue; + + if (map_ops[i].flags & GNTMAP_contains_pte) { + pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + + (map_ops[i].host_addr & ~PAGE_MASK)); + mfn = pte_mfn(*pte); + } else { + mfn = PFN_DOWN(map_ops[i].dev_bus_addr); + } + pfn = page_to_pfn(pages[i]); + + WARN_ON(PagePrivate(pages[i])); + SetPagePrivate(pages[i]); + set_page_private(pages[i], mfn); + pages[i]->index = pfn_to_mfn(pfn); + + if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { + ret = -ENOMEM; + goto out; + } + + if (m2p_override) { + ret = m2p_add_override(mfn, pages[i], kmap_ops ? + &kmap_ops[i] : NULL); + if (ret) + goto out; + } + } + +out: + if (lazy) + arch_leave_lazy_mmu_mode(); + + return ret; +} +EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping); + /* Add an MFN override for a particular page */ int m2p_add_override(unsigned long mfn, struct page *page, struct gnttab_map_grant_ref *kmap_op) @@ -899,13 +960,6 @@ int m2p_add_override(unsigned long mfn, struct page *page, "m2p_add_override: pfn %lx not mapped", pfn)) return -EINVAL; } - WARN_ON(PagePrivate(page)); - SetPagePrivate(page); - set_page_private(page, mfn); - page->index = pfn_to_mfn(pfn); - - if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) - return -ENOMEM; if (kmap_op != NULL) { if (!PageHighMem(page)) { @@ -943,20 +997,66 @@ int m2p_add_override(unsigned long mfn, struct page *page, return 0; } EXPORT_SYMBOL_GPL(m2p_add_override); + +int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) +{ + int i, ret = 0; + bool lazy = false; + + if (xen_feature(XENFEAT_auto_translated_physmap)) + return 0; + + if (m2p_override && + !in_interrupt() && + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { + arch_enter_lazy_mmu_mode(); + lazy = true; + } + + for (i = 0; i < count; i++) { + unsigned long mfn = get_phys_to_machine(page_to_pfn(pages[i])); + unsigned long pfn = page_to_pfn(pages[i]); + + if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { + ret = -EINVAL; + goto out; + } + + set_page_private(pages[i], INVALID_P2M_ENTRY); + WARN_ON(!PagePrivate(pages[i])); + ClearPagePrivate(pages[i]); + set_phys_to_machine(pfn, pages[i]->index); + + if (m2p_override) + ret = m2p_remove_override(pages[i], + kmap_ops ? + &kmap_ops[i] : NULL, + mfn); + if (ret) + goto out; + } + +out: + if (lazy) + arch_leave_lazy_mmu_mode(); + return ret; +} +EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping); + int m2p_remove_override(struct page *page, - struct gnttab_map_grant_ref *kmap_op) + struct gnttab_map_grant_ref *kmap_op, + unsigned long mfn) { unsigned long flags; - unsigned long mfn; unsigned long pfn; unsigned long uninitialized_var(address); unsigned level; pte_t *ptep = NULL; pfn = page_to_pfn(page); - mfn = get_phys_to_machine(pfn); - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) - return -EINVAL; if (!PageHighMem(page)) { address = (unsigned long)__va(pfn << PAGE_SHIFT); @@ -970,10 +1070,7 @@ int m2p_remove_override(struct page *page, spin_lock_irqsave(&m2p_override_lock, flags); list_del(&page->lru); spin_unlock_irqrestore(&m2p_override_lock, flags); - WARN_ON(!PagePrivate(page)); - ClearPagePrivate(page); - set_phys_to_machine(pfn, page->index); if (kmap_op != NULL) { if (!PageHighMem(page)) { struct multicall_space mcs; diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 6620b73..875025f 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST || !rb_next(&persistent_gnt->node)) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; @@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work) pages[segs_to_unmap] = persistent_gnt->page; if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; @@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work) kfree(persistent_gnt); } if (segs_to_unmap > 0) { - ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); } @@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif, GNTMAP_host_map, pages[i]->handle); pages[i]->handle = BLKBACK_INVALID_HANDLE; if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, - invcount); + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount); BUG_ON(ret); put_free_pages(blkif, unmap_pages, invcount); invcount = 0; } } if (invcount) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount); BUG_ON(ret); put_free_pages(blkif, unmap_pages, invcount); } @@ -740,7 +737,7 @@ again: } if (segs_to_map) { - ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map); + ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map); BUG_ON(ret); } diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 073b4a1..34a2704 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map) } pr_debug("map %d+%d\n", map->index, map->count); - err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, - map->pages, map->count); + err = gnttab_map_refs_userspace(map->map_ops, + use_ptemod ? map->kmap_ops : NULL, + map->pages, + map->count); if (err) return err; @@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) } } - err = gnttab_unmap_refs(map->unmap_ops + offset, - use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, - pages); + err = gnttab_unmap_refs_userspace(map->unmap_ops + offset, + use_ptemod ? map->kmap_ops + offset : NULL, + map->pages + offset, + pages); if (err) return err; diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 1ce1c40..5efacf8 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -928,15 +928,14 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count) } EXPORT_SYMBOL_GPL(gnttab_batch_copy); -int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, - struct gnttab_map_grant_ref *kmap_ops, - struct page **pages, unsigned int count) +static int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) { int i, ret; - bool lazy = false; - pte_t *pte; - unsigned long mfn; + BUG_ON(kmap_ops && !m2p_override); ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count); if (ret) return ret; @@ -947,88 +946,56 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, gnttab_retry_eagain_gop(GNTTABOP_map_grant_ref, map_ops + i, &map_ops[i].status, __func__); - /* this is basically a nop on x86 */ - if (xen_feature(XENFEAT_auto_translated_physmap)) { - for (i = 0; i < count; i++) { - if (map_ops[i].status) - continue; - set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT, - map_ops[i].dev_bus_addr >> PAGE_SHIFT); - } - return ret; - } - - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { - arch_enter_lazy_mmu_mode(); - lazy = true; - } - - for (i = 0; i < count; i++) { - /* Do not add to override if the map failed. */ - if (map_ops[i].status) - continue; - - if (map_ops[i].flags & GNTMAP_contains_pte) { - pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + - (map_ops[i].host_addr & ~PAGE_MASK)); - mfn = pte_mfn(*pte); - } else { - mfn = PFN_DOWN(map_ops[i].dev_bus_addr); - } - ret = m2p_add_override(mfn, pages[i], kmap_ops ? - &kmap_ops[i] : NULL); - if (ret) - goto out; - } - - out: - if (lazy) - arch_leave_lazy_mmu_mode(); + return set_foreign_p2m_mapping(map_ops, kmap_ops, pages, count, + m2p_override); +} - return ret; +int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_map_refs(map_ops, NULL, pages, count, false); } EXPORT_SYMBOL_GPL(gnttab_map_refs); -int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, - struct gnttab_map_grant_ref *kmap_ops, - struct page **pages, unsigned int count) +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count) { - int i, ret; - bool lazy = false; + return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true); +} +EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace); + +static int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count, + bool m2p_override) +{ + int ret; + BUG_ON(kmap_ops && !m2p_override); ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count); if (ret) return ret; - /* this is basically a nop on x86 */ - if (xen_feature(XENFEAT_auto_translated_physmap)) { - for (i = 0; i < count; i++) { - set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT, - INVALID_P2M_ENTRY); - } - return ret; - } - - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { - arch_enter_lazy_mmu_mode(); - lazy = true; - } - - for (i = 0; i < count; i++) { - ret = m2p_remove_override(pages[i], kmap_ops ? - &kmap_ops[i] : NULL); - if (ret) - goto out; - } - - out: - if (lazy) - arch_leave_lazy_mmu_mode(); + return clear_foreign_p2m_mapping(unmap_ops, kmap_ops, pages, count, + m2p_override); +} - return ret; +int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_unmap_refs(map_ops, NULL, pages, count, false); } EXPORT_SYMBOL_GPL(gnttab_unmap_refs); +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true); +} +EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace); + static unsigned nr_status_frames(unsigned nr_grant_frames) { BUG_ON(grefs_per_grant_frame == 0); diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 5acb1e4..2541c96 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -191,11 +191,15 @@ void gnttab_free_auto_xlat_frames(void); #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr)) int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, - struct gnttab_map_grant_ref *kmap_ops, struct page **pages, unsigned int count); +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count); int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, - struct gnttab_map_grant_ref *kunmap_ops, struct page **pages, unsigned int count); +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops, + struct gnttab_map_grant_ref *kunmap_ops, + struct page **pages, unsigned int count); /* Perform a batch of grant map/copy operations. Retry every batch slot * for which the hypervisor returns GNTST_eagain. This is typically due _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |