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banners=-,-,- X-VirusChecked: Checked Received: (qmail 31904 invoked from network); 5 Jul 2016 14:28:30 -0000 Received: from mx01.bbu.dsd.mx.bitdefender.com (HELO mx01.bbu.dsd.mx.bitdefender.com) (91.199.104.161) by server-16.tower-21.messagelabs.com with DHE-RSA-AES128-GCM-SHA256 encrypted SMTP; 5 Jul 2016 14:28:30 -0000 Received: (qmail 18898 invoked from network); 5 Jul 2016 17:28:29 +0300 Received: from unknown (HELO mx-sr.buh.bitdefender.com) (10.17.80.103) by mx01.bbu.dsd.mx.bitdefender.com with AES256-GCM-SHA384 encrypted SMTP; 5 Jul 2016 17:28:29 +0300 Received: from smtp01.buh.bitdefender.com (unknown [10.17.80.75]) by mx-sr.buh.bitdefender.com (Postfix) with ESMTP id 70F877FC01 for ; Tue, 5 Jul 2016 17:28:28 +0300 (EEST) Received: (qmail 11259 invoked from network); 5 Jul 2016 17:28:28 +0300 Received: from 188-24-34-246.rdsnet.ro (HELO localhost.localdomain) (czuzu@bitdefender.com@188.24.34.246) by smtp01.buh.bitdefender.com with SMTP; 5 Jul 2016 17:28:28 +0300 From: Corneliu ZUZU To: xen-devel@lists.xen.org Date: Tue, 5 Jul 2016 17:28:22 +0300 Message-Id: <1467728902-13725-1-git-send-email-czuzu@bitdefender.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1467728717-13592-1-git-send-email-czuzu@bitdefender.com> References: <1467728717-13592-1-git-send-email-czuzu@bitdefender.com> X-BitDefender-Scanner: Clean, Agent: BitDefender qmail 3.1.6 on smtp01.buh.bitdefender.com, sigver: 7.66188 X-BitDefender-Spam: No (0) X-BitDefender-SpamStamp: Build: [Engines: 2.15.6.911, Dats: 425435, Stamp: 3], Multi: [Enabled, t: (0.000011, 0.006812)], BW: [Enabled, t: (0.000007,0.000002)], RBL DNSBL: [Disabled], APM: [Enabled, Score: 500, t: (0.005214), Flags: BB9BAF5C; NN_NO_CONTENT_TYPE; NN_LEGIT_SUMM_400_WORDS; NN_NO_LINK_NMD; NN_LEGIT_BITDEFENDER; NN_LEGIT_S_SQARE_BRACKETS; NN_LEGIT_MAILING_LIST_TO], SGN: [Enabled, t: (0.011163)], URL: [Enabled, t: (0.000004)], RTDA: [Enabled, t: (0.017309), Hit: No, Details: v2.3.10; Id: 2m1ghhv.1amgktn52.jmer], total: 0(775) X-BitDefender-CF-Stamp: none Cc: Tamas K Lengyel , Razvan Cojocaru , George Dunlap , Andrew Cooper , Paul Durrant , Jan Beulich Subject: [Xen-devel] [PATCH v2 3/7] x86/vm-event/monitor: don't compromise monitor_write_data on domain cleanup X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP The arch_vm_event structure is dynamically allocated and freed @ vm_event_cleanup_domain. This cleanup is triggered e.g. when the toolstack user disables domain monitoring (xc_monitor_disable), which in turn effectively discards any information that was in arch_vm_event.write_data. But this can yield unexpected behavior since if a CR-write was awaiting to be committed on the scheduling tail (hvm_do_resume->arch_monitor_write_data) before xc_monitor_disable is called, then the domain CR write is wrongfully ignored, which of course, in these cases, can easily render a domain crash. To fix the issue, this patch makes arch_vm_event.emul_read_data dynamically allocated and only frees that in vm_event_cleanup_domain, instead of the whole arch_vcpu.vm_event structure, which with this patch will only be freed on vcpu/domain destroyal. Signed-off-by: Corneliu ZUZU Acked-by: Razvan Cojocaru Acked-by: George Dunlap Acked-by: George Dunlap --- Changed since v1: * arch_vcpu.vm_event made pointer again to avoid eating memory from arch_vcpu structure --- xen/arch/x86/domain.c | 9 +++++++-- xen/arch/x86/hvm/emulate.c | 6 +++--- xen/arch/x86/hvm/hvm.c | 2 ++ xen/arch/x86/mm/p2m.c | 2 +- xen/arch/x86/vm_event.c | 22 ++++++++++++++++------ xen/common/vm_event.c | 11 +++++++++++ xen/include/asm-x86/monitor.h | 4 +++- xen/include/asm-x86/vm_event.h | 2 +- 8 files changed, 44 insertions(+), 14 deletions(-) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index bb59247..0313208 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include #include @@ -492,8 +493,12 @@ int vcpu_initialise(struct vcpu *v) void vcpu_destroy(struct vcpu *v) { - xfree(v->arch.vm_event); - v->arch.vm_event = NULL; + if ( unlikely(v->arch.vm_event) ) + { + xfree(v->arch.vm_event->emul_read_data); + xfree(v->arch.vm_event); + v->arch.vm_event = NULL; + } if ( is_pv_32bit_vcpu(v) ) { diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index 855af4d..3880df1 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -73,12 +73,12 @@ static int set_context_data(void *buffer, unsigned int size) { struct vcpu *curr = current; - if ( curr->arch.vm_event ) + if ( curr->arch.vm_event && curr->arch.vm_event->emul_read_data ) { unsigned int safe_size = - min(size, curr->arch.vm_event->emul_read_data.size); + min(size, curr->arch.vm_event->emul_read_data->size); - memcpy(buffer, curr->arch.vm_event->emul_read_data.data, safe_size); + memcpy(buffer, curr->arch.vm_event->emul_read_data->data, safe_size); memset(buffer + safe_size, 0, size - safe_size); return X86EMUL_OKAY; } diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index e3829d2..ac6d9eb 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -479,6 +479,8 @@ void hvm_do_resume(struct vcpu *v) { enum emul_kind kind = EMUL_KIND_NORMAL; + ASSERT(v->arch.vm_event->emul_read_data); + if ( v->arch.vm_event->emulate_flags & VM_EVENT_FLAG_SET_EMUL_READ_DATA ) kind = EMUL_KIND_SET_CONTEXT; diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index 16733a4..6616626 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -1642,7 +1642,7 @@ void p2m_mem_access_emulate_check(struct vcpu *v, v->arch.vm_event->emulate_flags = violation ? rsp->flags : 0; if ( (rsp->flags & VM_EVENT_FLAG_SET_EMUL_READ_DATA) ) - v->arch.vm_event->emul_read_data = rsp->data.emul_read_data; + *v->arch.vm_event->emul_read_data = rsp->data.emul_read_data; } } diff --git a/xen/arch/x86/vm_event.c b/xen/arch/x86/vm_event.c index 80f84d6..0e25e4d 100644 --- a/xen/arch/x86/vm_event.c +++ b/xen/arch/x86/vm_event.c @@ -30,12 +30,18 @@ int vm_event_init_domain(struct domain *d) for_each_vcpu ( d, v ) { - if ( v->arch.vm_event ) + if ( likely(!v->arch.vm_event) ) + { + v->arch.vm_event = xzalloc(struct arch_vm_event); + if ( !v->arch.vm_event ) + return -ENOMEM; + } + else if ( unlikely(v->arch.vm_event->emul_read_data) ) continue; - v->arch.vm_event = xzalloc(struct arch_vm_event); - - if ( !v->arch.vm_event ) + v->arch.vm_event->emul_read_data = + xzalloc(struct vm_event_emul_read_data); + if ( !v->arch.vm_event->emul_read_data ) return -ENOMEM; } @@ -52,8 +58,12 @@ void vm_event_cleanup_domain(struct domain *d) for_each_vcpu ( d, v ) { - xfree(v->arch.vm_event); - v->arch.vm_event = NULL; + if ( likely(!v->arch.vm_event) ) + continue; + + v->arch.vm_event->emulate_flags = 0; + xfree(v->arch.vm_event->emul_read_data); + v->arch.vm_event->emul_read_data = NULL; } d->arch.mem_access_emulate_each_rep = 0; diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c index 17d2716..75bbbab 100644 --- a/xen/common/vm_event.c +++ b/xen/common/vm_event.c @@ -534,6 +534,8 @@ static void mem_sharing_notification(struct vcpu *v, unsigned int port) /* Clean up on domain destruction */ void vm_event_cleanup(struct domain *d) { + struct vcpu *v; + #ifdef CONFIG_HAS_MEM_PAGING if ( d->vm_event->paging.ring_page ) { @@ -560,6 +562,15 @@ void vm_event_cleanup(struct domain *d) (void)vm_event_disable(d, &d->vm_event->share); } #endif + + for_each_vcpu ( d, v ) + { + if ( unlikely(v->arch.vm_event) ) + { + xfree(v->arch.vm_event); + v->arch.vm_event = NULL; + } + } } int vm_event_domctl(struct domain *d, xen_domctl_vm_event_op_t *vec, diff --git a/xen/include/asm-x86/monitor.h b/xen/include/asm-x86/monitor.h index 0611681..a094c0d 100644 --- a/xen/include/asm-x86/monitor.h +++ b/xen/include/asm-x86/monitor.h @@ -26,6 +26,7 @@ #include #include #include +#include #define monitor_ctrlreg_bitmask(ctrlreg_index) (1U << (ctrlreg_index)) @@ -48,7 +49,8 @@ int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op *mop) * Enabling mem_access_emulate_each_rep without a vm_event subscriber * is meaningless. */ - if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event ) + if ( d->max_vcpus && d->vcpu[0] && d->vcpu[0]->arch.vm_event && + d->vcpu[0]->arch.vm_event->emul_read_data ) d->arch.mem_access_emulate_each_rep = !!mop->event; else rc = -EINVAL; diff --git a/xen/include/asm-x86/vm_event.h b/xen/include/asm-x86/vm_event.h index 026f42e..557f353 100644 --- a/xen/include/asm-x86/vm_event.h +++ b/xen/include/asm-x86/vm_event.h @@ -28,7 +28,7 @@ */ struct arch_vm_event { uint32_t emulate_flags; - struct vm_event_emul_read_data emul_read_data; + struct vm_event_emul_read_data *emul_read_data; struct monitor_write_data write_data; };