diff options
| -rw-r--r-- | arch/x86/include/asm/xen/page.h | 16 | ||||
| -rw-r--r-- | arch/x86/xen/p2m.c | 80 |
2 files changed, 93 insertions, 3 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 8760cc60a21..50f0a0f6bd6 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -42,6 +42,11 @@ extern unsigned int machine_to_phys_order; extern unsigned long get_phys_to_machine(unsigned long pfn); extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn); +extern void m2p_add_override(unsigned long mfn, struct page *page); +extern void m2p_remove_override(struct page *page); +extern struct page *m2p_find_override(unsigned long mfn); +extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); + static inline unsigned long pfn_to_mfn(unsigned long pfn) { unsigned long mfn; @@ -72,9 +77,6 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) if (xen_feature(XENFEAT_auto_translated_physmap)) return mfn; - if (unlikely((mfn >> machine_to_phys_order) != 0)) - return ~0; - pfn = 0; /* * The array access can fail (e.g., device space beyond end of RAM). @@ -83,6 +85,14 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) */ __get_user(pfn, &machine_to_phys_mapping[mfn]); + /* + * If this appears to be a foreign mfn (because the pfn + * doesn't map back to the mfn), then check the local override + * table to see if there's a better pfn to use. + */ + if (get_phys_to_machine(pfn) != mfn) + pfn = m2p_find_override_pfn(mfn, pfn); + return pfn; } diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 259ec3bb8b6..8db19d50c46 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -27,6 +27,8 @@ #include <linux/init.h> #include <linux/module.h> +#include <linux/list.h> +#include <linux/hash.h> #include <asm/cache.h> #include <asm/setup.h> @@ -37,6 +39,8 @@ #include "xen-ops.h" +static void __init m2p_override_init(void); + unsigned long xen_max_p2m_pfn __read_mostly; #define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long)) @@ -234,6 +238,8 @@ void __init xen_build_dynamic_phys_to_machine(void) p2m_top[topidx][mididx] = &mfn_list[pfn]; } + + m2p_override_init(); } unsigned long get_phys_to_machine(unsigned long pfn) @@ -374,3 +380,77 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) return true; } + +#define M2P_OVERRIDE_HASH_SHIFT 10 +#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT) + +static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH); +static DEFINE_SPINLOCK(m2p_override_lock); + +static void __init m2p_override_init(void) +{ + unsigned i; + + m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, + sizeof(unsigned long)); + + for (i = 0; i < M2P_OVERRIDE_HASH; i++) + INIT_LIST_HEAD(&m2p_overrides[i]); +} + +static unsigned long mfn_hash(unsigned long mfn) +{ + return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT); +} + +/* Add an MFN override for a particular page */ +void m2p_add_override(unsigned long mfn, struct page *page) +{ + unsigned long flags; + page->private = mfn; + + spin_lock_irqsave(&m2p_override_lock, flags); + list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]); + spin_unlock_irqrestore(&m2p_override_lock, flags); +} + +void m2p_remove_override(struct page *page) +{ + unsigned long flags; + spin_lock_irqsave(&m2p_override_lock, flags); + list_del(&page->lru); + spin_unlock_irqrestore(&m2p_override_lock, flags); +} + +struct page *m2p_find_override(unsigned long mfn) +{ + unsigned long flags; + struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)]; + struct page *p, *ret; + + ret = NULL; + + spin_lock_irqsave(&m2p_override_lock, flags); + + list_for_each_entry(p, bucket, lru) { + if (p->private == mfn) { + ret = p; + break; + } + } + + spin_unlock_irqrestore(&m2p_override_lock, flags); + + return ret; +} + +unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn) +{ + struct page *p = m2p_find_override(mfn); + unsigned long ret = pfn; + + if (p) + ret = page_to_pfn(p); + + return ret; +} |