From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: [PATCHv6 2/2] x86/ept: defer the invalidation until the p2m lock is released Date: Fri, 18 Dec 2015 13:50:34 +0000 Message-ID: <1450446634-8762-3-git-send-email-david.vrabel@citrix.com> References: <1450446634-8762-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1a9vQn-0004ne-Up for xen-devel@lists.xenproject.org; Fri, 18 Dec 2015 13:50:50 +0000 In-Reply-To: <1450446634-8762-1-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: Kevin Tian , Jun Nakajima , George Dunlap , Andrew Cooper , Tim Deegan , David Vrabel , Jan Beulich List-Id: xen-devel@lists.xenproject.org Holding the p2m lock while calling ept_sync_domain() is very expensive since it does a on_selected_cpus() call. IPIs on many socket machines can be very slows and on_selected_cpus() is serialized. It is safe to defer the invalidate until the p2m lock is released except for two cases: 1. When freeing a page table page (since partial translations may be cached). 2. When reclaiming a zero page as part of PoD. For these cases, add p2m_tlb_flush_sync() calls which will immediately perform the invalidate before the page is freed or reclaimed. Signed-off-by: David Vrabel --- v6: - Move p2m_tlb_flush_sync() to immediately before p2m_free_ptp(). It was called all the time otherwise. v5: - add p2m_tlb_flush_sync() and call it before freeing pgae table pages and reclaiming zeroed pod pages. v2: - use per-p2m list for deferred pages. - update synced_mask while holding write lock. --- xen/arch/x86/mm/mm-locks.h | 23 +++++++++++++++-------- xen/arch/x86/mm/p2m-ept.c | 42 ++++++++++++++++++++++++++++++++++-------- xen/arch/x86/mm/p2m-pod.c | 2 ++ xen/arch/x86/mm/p2m.c | 14 ++++++++++++++ xen/include/asm-x86/p2m.h | 10 ++++++++++ 5 files changed, 75 insertions(+), 16 deletions(-) diff --git a/xen/arch/x86/mm/mm-locks.h b/xen/arch/x86/mm/mm-locks.h index 76c7217..b1a92e2 100644 --- a/xen/arch/x86/mm/mm-locks.h +++ b/xen/arch/x86/mm/mm-locks.h @@ -263,14 +263,21 @@ declare_mm_lock(altp2mlist) */ declare_mm_rwlock(altp2m); -#define p2m_lock(p) \ -{ \ - if ( p2m_is_altp2m(p) ) \ - mm_write_lock(altp2m, &(p)->lock); \ - else \ - mm_write_lock(p2m, &(p)->lock); \ -} -#define p2m_unlock(p) mm_write_unlock(&(p)->lock); +#define p2m_lock(p) \ + do { \ + if ( p2m_is_altp2m(p) ) \ + mm_write_lock(altp2m, &(p)->lock); \ + else \ + mm_write_lock(p2m, &(p)->lock); \ + (p)->defer_flush++; \ + } while (0) +#define p2m_unlock(p) \ + do { \ + if ( --(p)->defer_flush == 0 ) \ + p2m_tlb_flush_and_unlock(p); \ + else \ + mm_write_unlock(&(p)->lock); \ + } while (0) #define gfn_lock(p,g,o) p2m_lock(p) #define gfn_unlock(p,g,o) p2m_unlock(p) #define p2m_read_lock(p) mm_read_lock(p2m, &(p)->lock) diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c index c094320..43c7f1b 100644 --- a/xen/arch/x86/mm/p2m-ept.c +++ b/xen/arch/x86/mm/p2m-ept.c @@ -263,6 +263,7 @@ static void ept_free_entry(struct p2m_domain *p2m, ept_entry_t *ept_entry, int l unmap_domain_page(epte); } + p2m_tlb_flush_sync(p2m); p2m_free_ptp(p2m, mfn_to_page(ept_entry->mfn)); } @@ -1095,15 +1096,10 @@ static void __ept_sync_domain(void *info) */ } -void ept_sync_domain(struct p2m_domain *p2m) +static void ept_sync_domain_prepare(struct p2m_domain *p2m) { struct domain *d = p2m->domain; struct ept_data *ept = &p2m->ept; - /* Only if using EPT and this domain has some VCPUs to dirty. */ - if ( !paging_mode_hap(d) || !d->vcpu || !d->vcpu[0] ) - return; - - ASSERT(local_irq_is_enabled()); if ( nestedhvm_enabled(d) && !p2m_is_nestedp2m(p2m) ) p2m_flush_nestedp2m(d); @@ -1116,9 +1112,38 @@ void ept_sync_domain(struct p2m_domain *p2m) * of an EP4TA reuse is still needed. */ cpumask_setall(ept->invalidate); +} + +static void ept_sync_domain_mask(struct p2m_domain *p2m, const cpumask_t *mask) +{ + on_selected_cpus(mask, __ept_sync_domain, p2m, 1); +} + +void ept_sync_domain(struct p2m_domain *p2m) +{ + struct domain *d = p2m->domain; - on_selected_cpus(d->domain_dirty_cpumask, - __ept_sync_domain, p2m, 1); + /* Only if using EPT and this domain has some VCPUs to dirty. */ + if ( !paging_mode_hap(d) || !d->vcpu || !d->vcpu[0] ) + return; + + ept_sync_domain_prepare(p2m); + + if ( p2m->defer_flush ) + { + p2m->need_flush = 1; + return; + } + + ept_sync_domain_mask(p2m, d->domain_dirty_cpumask); +} + +static void ept_flush_and_unlock(struct p2m_domain *p2m, bool_t unlock) +{ + p2m->need_flush = 0; + if ( unlock ) + mm_write_unlock(&p2m->lock); + ept_sync_domain_mask(p2m, p2m->domain->domain_dirty_cpumask); } static void ept_enable_pml(struct p2m_domain *p2m) @@ -1169,6 +1194,7 @@ int ept_p2m_init(struct p2m_domain *p2m) p2m->change_entry_type_range = ept_change_entry_type_range; p2m->memory_type_changed = ept_memory_type_changed; p2m->audit_p2m = NULL; + p2m->flush_and_unlock = ept_flush_and_unlock; /* Set the memory type used when accessing EPT paging structures. */ ept->ept_mt = EPT_DEFAULT_MT; diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c index ea16d3e..a5d672e 100644 --- a/xen/arch/x86/mm/p2m-pod.c +++ b/xen/arch/x86/mm/p2m-pod.c @@ -886,6 +886,8 @@ p2m_pod_zero_check(struct p2m_domain *p2m, unsigned long *gfns, int count) } } + p2m_tlb_flush_sync(p2m); + /* Now check each page for real */ for ( i=0; i < count; i++ ) { diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index ed0bbd7..efb15cd 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -324,6 +324,20 @@ void p2m_flush_hardware_cached_dirty(struct domain *d) } } +void p2m_tlb_flush_sync(struct p2m_domain *p2m) +{ + if ( p2m->need_flush ) + p2m->flush_and_unlock(p2m, 0); +} + +void p2m_tlb_flush_and_unlock(struct p2m_domain *p2m) +{ + if ( p2m->need_flush ) + p2m->flush_and_unlock(p2m, 1); + else + mm_write_unlock(&p2m->lock); +} + mfn_t __get_gfn_type_access(struct p2m_domain *p2m, unsigned long gfn, p2m_type_t *t, p2m_access_t *a, p2m_query_t q, unsigned int *page_order, bool_t locked) diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index fa46dd9..9c394c2 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -261,6 +261,10 @@ struct p2m_domain { unsigned long gfn, l1_pgentry_t *p, l1_pgentry_t new, unsigned int level); long (*audit_p2m)(struct p2m_domain *p2m); + void (*flush_and_unlock)(struct p2m_domain *p2m, bool_t unlock); + + unsigned int defer_flush; + bool_t need_flush; /* Default P2M access type for each page in the the domain: new pages, * swapped in pages, cleared pages, and pages that are ambiguously @@ -353,6 +357,12 @@ static inline bool_t p2m_is_altp2m(const struct p2m_domain *p2m) #define p2m_get_pagetable(p2m) ((p2m)->phys_table) +/* + * Ensure any deferred p2m TLB flush has been completed on all VCPUs. + */ +void p2m_tlb_flush_sync(struct p2m_domain *p2m); +void p2m_tlb_flush_and_unlock(struct p2m_domain *p2m); + /**** p2m query accessors. They lock p2m_lock, and thus serialize * lookups wrt modifications. They _do not_ release the lock on exit. * After calling any of the variants below, caller needs to use -- 2.1.4