diff options
Diffstat (limited to 'xen/arch/x86/mm/shadow/private.h')
| -rw-r--r-- | xen/arch/x86/mm/shadow/private.h | 69 |
1 files changed, 68 insertions, 1 deletions
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h index 52ea6d5d16..8a6b93f4d8 100644 --- a/xen/arch/x86/mm/shadow/private.h +++ b/xen/arch/x86/mm/shadow/private.h @@ -61,8 +61,9 @@ extern int shadow_audit_enable; #define SHOPT_PREFETCH 0x08 /* Shadow multiple entries per fault */ #define SHOPT_LINUX_L3_TOPLEVEL 0x10 /* Pin l3es on early 64bit linux */ #define SHOPT_SKIP_VERIFY 0x20 /* Skip PTE v'fy when safe to do so */ +#define SHOPT_VIRTUAL_TLB 0x40 /* Cache guest v->p translations */ -#define SHADOW_OPTIMIZATIONS 0x3f +#define SHADOW_OPTIMIZATIONS 0x7f /****************************************************************************** @@ -649,6 +650,72 @@ struct x86_emulate_ops *shadow_init_emulation( void shadow_continue_emulation( struct sh_emulate_ctxt *sh_ctxt, struct cpu_user_regs *regs); + +#if (SHADOW_OPTIMIZATIONS & SHOPT_VIRTUAL_TLB) +/**************************************************************************/ +/* Virtual TLB entries + * + * We keep a cache of virtual-to-physical translations that we have seen + * since the last TLB flush. This is safe to use for frame translations, + * but callers that use the rights need to re-check the actual guest tables + * before triggering a fault. + * + * Lookups and updates are protected by a per-vTLB (and hence per-vcpu) + * lock. This lock is held *only* while reading or writing the table, + * so it is safe to take in any non-interrupt context. Most lookups + * happen with v==current, so we expect contention to be low. + */ + +#define VTLB_ENTRIES 13 + +struct shadow_vtlb { + unsigned long page_number; /* Guest virtual address >> PAGE_SHIFT */ + unsigned long frame_number; /* Guest physical address >> PAGE_SHIFT */ + u32 flags; /* Accumulated guest pte flags, or 0 for an empty slot. */ +}; + +/* Call whenever the guest flushes hit actual TLB */ +static inline void vtlb_flush(struct vcpu *v) +{ + spin_lock(&v->arch.paging.vtlb_lock); + memset(v->arch.paging.vtlb, 0, VTLB_ENTRIES * sizeof (struct shadow_vtlb)); + spin_unlock(&v->arch.paging.vtlb_lock); +} + +static inline int vtlb_hash(unsigned long page_number) +{ + return page_number % VTLB_ENTRIES; +} + +/* Put a translation into the vTLB, potentially clobbering an old one */ +static inline void vtlb_insert(struct vcpu *v, struct shadow_vtlb entry) +{ + spin_lock(&v->arch.paging.vtlb_lock); + v->arch.paging.vtlb[vtlb_hash(entry.page_number)] = entry; + spin_unlock(&v->arch.paging.vtlb_lock); +} + +/* Look a translation up in the vTLB. Returns 0 if not found. */ +static inline int vtlb_lookup(struct vcpu *v, unsigned long va, + struct shadow_vtlb *result) +{ + unsigned long page_number = va >> PAGE_SHIFT; + int rv = 0; + int i = vtlb_hash(page_number); + + spin_lock(&v->arch.paging.vtlb_lock); + if ( v->arch.paging.vtlb[i].flags != 0 + && v->arch.paging.vtlb[i].page_number == page_number ) + { + rv = 1; + result[0] = v->arch.paging.vtlb[i]; + } + spin_unlock(&v->arch.paging.vtlb_lock); + return rv; +} +#endif /* (SHADOW_OPTIMIZATIONS & SHOPT_VIRTUAL_TLB) */ + + #endif /* _XEN_SHADOW_PRIVATE_H */ /* |