diff options
Diffstat (limited to 'arch/x86/xen/p2m.c')
| -rw-r--r-- | arch/x86/xen/p2m.c | 122 |
1 files changed, 103 insertions, 19 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index b2e91d40a4c..72213da605f 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -196,9 +196,11 @@ RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3); /* When we populate back during bootup, the amount of pages can vary. The * max we have is seen is 395979, but that does not mean it can't be more. - * But some machines can have 3GB I/O holes even. So lets reserve enough - * for 4GB of I/O and E820 holes. */ -RESERVE_BRK(p2m_populated, PMD_SIZE * 4); + * Some machines can have 3GB I/O holes even. With early_can_reuse_p2m_middle + * it can re-use Xen provided mfn_list array, so we only need to allocate at + * most three P2M top nodes. */ +RESERVE_BRK(p2m_populated, PAGE_SIZE * 3); + static inline unsigned p2m_top_index(unsigned long pfn) { BUG_ON(pfn >= MAX_P2M_PFN); @@ -575,12 +577,99 @@ static bool __init early_alloc_p2m(unsigned long pfn) } return true; } + +/* + * Skim over the P2M tree looking at pages that are either filled with + * INVALID_P2M_ENTRY or with 1:1 PFNs. If found, re-use that page and + * replace the P2M leaf with a p2m_missing or p2m_identity. + * Stick the old page in the new P2M tree location. + */ +bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn) +{ + unsigned topidx; + unsigned mididx; + unsigned ident_pfns; + unsigned inv_pfns; + unsigned long *p2m; + unsigned long *mid_mfn_p; + unsigned idx; + unsigned long pfn; + + /* We only look when this entails a P2M middle layer */ + if (p2m_index(set_pfn)) + return false; + + for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) { + topidx = p2m_top_index(pfn); + + if (!p2m_top[topidx]) + continue; + + if (p2m_top[topidx] == p2m_mid_missing) + continue; + + mididx = p2m_mid_index(pfn); + p2m = p2m_top[topidx][mididx]; + if (!p2m) + continue; + + if ((p2m == p2m_missing) || (p2m == p2m_identity)) + continue; + + if ((unsigned long)p2m == INVALID_P2M_ENTRY) + continue; + + ident_pfns = 0; + inv_pfns = 0; + for (idx = 0; idx < P2M_PER_PAGE; idx++) { + /* IDENTITY_PFNs are 1:1 */ + if (p2m[idx] == IDENTITY_FRAME(pfn + idx)) + ident_pfns++; + else if (p2m[idx] == INVALID_P2M_ENTRY) + inv_pfns++; + else + break; + } + if ((ident_pfns == P2M_PER_PAGE) || (inv_pfns == P2M_PER_PAGE)) + goto found; + } + return false; +found: + /* Found one, replace old with p2m_identity or p2m_missing */ + p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing); + /* And the other for save/restore.. */ + mid_mfn_p = p2m_top_mfn_p[topidx]; + /* NOTE: Even if it is a p2m_identity it should still be point to + * a page filled with INVALID_P2M_ENTRY entries. */ + mid_mfn_p[mididx] = virt_to_mfn(p2m_missing); + + /* Reset where we want to stick the old page in. */ + topidx = p2m_top_index(set_pfn); + mididx = p2m_mid_index(set_pfn); + + /* This shouldn't happen */ + if (WARN_ON(p2m_top[topidx] == p2m_mid_missing)) + early_alloc_p2m(set_pfn); + + if (WARN_ON(p2m_top[topidx][mididx] != p2m_missing)) + return false; + + p2m_init(p2m); + p2m_top[topidx][mididx] = p2m; + mid_mfn_p = p2m_top_mfn_p[topidx]; + mid_mfn_p[mididx] = virt_to_mfn(p2m); + + return true; +} bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn) { if (unlikely(!__set_phys_to_machine(pfn, mfn))) { if (!early_alloc_p2m(pfn)) return false; + if (early_can_reuse_p2m_middle(pfn, mfn)) + return __set_phys_to_machine(pfn, mfn); + if (!early_alloc_p2m_middle(pfn, false /* boundary crossover OK!*/)) return false; @@ -739,9 +828,6 @@ int m2p_add_override(unsigned long mfn, struct page *page, xen_mc_issue(PARAVIRT_LAZY_MMU); } - /* let's use dev_bus_addr to record the old mfn instead */ - kmap_op->dev_bus_addr = page->index; - page->index = (unsigned long) kmap_op; } spin_lock_irqsave(&m2p_override_lock, flags); list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); @@ -768,7 +854,8 @@ int m2p_add_override(unsigned long mfn, struct page *page, return 0; } EXPORT_SYMBOL_GPL(m2p_add_override); -int m2p_remove_override(struct page *page, bool clear_pte) +int m2p_remove_override(struct page *page, + struct gnttab_map_grant_ref *kmap_op) { unsigned long flags; unsigned long mfn; @@ -798,10 +885,8 @@ int m2p_remove_override(struct page *page, bool clear_pte) WARN_ON(!PagePrivate(page)); ClearPagePrivate(page); - if (clear_pte) { - struct gnttab_map_grant_ref *map_op = - (struct gnttab_map_grant_ref *) page->index; - set_phys_to_machine(pfn, map_op->dev_bus_addr); + set_phys_to_machine(pfn, page->index); + if (kmap_op != NULL) { if (!PageHighMem(page)) { struct multicall_space mcs; struct gnttab_unmap_grant_ref *unmap_op; @@ -813,13 +898,13 @@ int m2p_remove_override(struct page *page, bool clear_pte) * issued. In this case handle is going to -1 because * it hasn't been modified yet. */ - if (map_op->handle == -1) + if (kmap_op->handle == -1) xen_mc_flush(); /* - * Now if map_op->handle is negative it means that the + * Now if kmap_op->handle is negative it means that the * hypercall actually returned an error. */ - if (map_op->handle == GNTST_general_error) { + if (kmap_op->handle == GNTST_general_error) { printk(KERN_WARNING "m2p_remove_override: " "pfn %lx mfn %lx, failed to modify kernel mappings", pfn, mfn); @@ -829,8 +914,8 @@ int m2p_remove_override(struct page *page, bool clear_pte) mcs = xen_mc_entry( sizeof(struct gnttab_unmap_grant_ref)); unmap_op = mcs.args; - unmap_op->host_addr = map_op->host_addr; - unmap_op->handle = map_op->handle; + unmap_op->host_addr = kmap_op->host_addr; + unmap_op->handle = kmap_op->handle; unmap_op->dev_bus_addr = 0; MULTI_grant_table_op(mcs.mc, @@ -841,10 +926,9 @@ int m2p_remove_override(struct page *page, bool clear_pte) set_pte_at(&init_mm, address, ptep, pfn_pte(pfn, PAGE_KERNEL)); __flush_tlb_single(address); - map_op->host_addr = 0; + kmap_op->host_addr = 0; } - } else - set_phys_to_machine(pfn, page->index); + } /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present * somewhere in this domain, even before being added to the |