From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965356Ab2JAXkv (ORCPT ); Mon, 1 Oct 2012 19:40:51 -0400 Received: from 1wt.eu ([62.212.114.60]:34975 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932458Ab2JAW7c (ORCPT ); Mon, 1 Oct 2012 18:59:32 -0400 Message-Id: <20121001225159.521191640@1wt.eu> User-Agent: quilt/0.48-1 Date: Tue, 02 Oct 2012 00:52:42 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Michael Ellerman , Avi Kivity , Willy Tarreau Subject: [ 045/180] KVM: Ensure all vcpus are consistent with in-kernel irqchip settings In-Reply-To: <6a854f579a99b4fe2efaca1057e8ae22@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Avi Kivity commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e upstream If some vcpus are created before KVM_CREATE_IRQCHIP, then irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to potential NULL pointer dereferences. Fix by: - ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called - ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP This is somewhat long winded because vcpu->arch.apic is created without kvm->lock held. Based on earlier patch by Michael Ellerman. Signed-off-by: Michael Ellerman Signed-off-by: Avi Kivity [dannf: backported to Debian's 2.6.32] Signed-off-by: Willy Tarreau --- arch/ia64/kvm/kvm-ia64.c | 5 +++++ arch/x86/kvm/x86.c | 8 ++++++++ include/linux/kvm_host.h | 7 +++++++ virt/kvm/kvm_main.c | 4 ++++ 4 files changed, 24 insertions(+), 0 deletions(-) diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c index 2eb6365..416122b 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -1185,6 +1185,11 @@ out: #define PALE_RESET_ENTRY 0x80000000ffffffb0UL +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) +{ + return irqchip_in_kernel(vcpu->kcm) == (vcpu->arch.apic != NULL); +} + int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) { struct kvm_vcpu *v; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5908461..271fddf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2280,6 +2280,9 @@ long kvm_arch_vm_ioctl(struct file *filp, r = -EEXIST; if (kvm->arch.vpic) goto create_irqchip_unlock; + r = -EINVAL; + if (atomic_read(&kvm->online_vcpus)) + goto create_irqchip_unlock; r = -ENOMEM; vpic = kvm_create_pic(kvm); if (vpic) { @@ -5027,6 +5030,11 @@ void kvm_arch_check_processor_compat(void *rtn) kvm_x86_ops->check_processor_compatibility(rtn); } +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) +{ + return irqchip_in_kernel(vcpu->kvm) == (vcpu->arch.apic != NULL); +} + int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) { struct page *page; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c728a50..8bfed57 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -556,5 +556,12 @@ static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu) { return vcpu->kvm->bsp_vcpu_id == vcpu->vcpu_id; } + +bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu); + +#else + +static inline bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) { return true; } + #endif #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 311ec18..82b6fdc 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1857,6 +1857,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) return r; mutex_lock(&kvm->lock); + if (!kvm_vcpu_compatible(vcpu)) { + r = -EINVAL; + goto vcpu_destroy; + } if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) { r = -EINVAL; goto vcpu_destroy; -- 1.7.2.1.45.g54fbc