Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755656Ab2E1D4z (ORCPT ); Sun, 27 May 2012 23:56:55 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51800 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752903Ab2E1D24 (ORCPT ); Sun, 27 May 2012 23:28:56 -0400 Message-Id: <20120528031203.152711779@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 28 May 2012 04:12:04 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Marcelo Tosatti , Avi Kivity , Michael Ellerman , Greg Kroah-Hartman Subject: [ 002/117] KVM: Ensure all vcpus are consistent with in-kernel irqchip settings In-Reply-To: <20120528031202.829379252@decadent.org.uk> X-SA-Exim-Connect-IP: 192.168.4.185 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3508 Lines: 116 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marcelo Tosatti From: Avi Kivity (cherry picked from commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e) 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- 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 43f4c92..7073185 100644 --- a/arch/ia64/kvm/kvm-ia64.c +++ b/arch/ia64/kvm/kvm-ia64.c @@ -1169,6 +1169,11 @@ 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 e04cae1..4fc5323 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3579,6 +3579,9 @@ 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) { @@ -6486,6 +6489,11 @@ 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 35410ef..6136821 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -744,6 +744,13 @@ 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 #ifdef __KVM_HAVE_DEVICE_ASSIGNMENT diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 9ffac2e..ec747dc 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1667,6 +1667,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) goto vcpu_destroy; mutex_lock(&kvm->lock); + if (!kvm_vcpu_compatible(vcpu)) { + r = -EINVAL; + goto unlock_vcpu_destroy; + } if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) { r = -EINVAL; goto unlock_vcpu_destroy; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/