This is a note to let you know that I've just added the patch titled
KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-ensure-all-vcpus-are-consistent-with-in-kernel-irqchip-settings.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From [email protected] Wed May 9 06:14:29 2012
From: Avi Kivity <[email protected]>
Date: Wed, 9 May 2012 16:10:42 +0300
Subject: KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
To: [email protected]
Cc: Marcelo Tosatti <[email protected]>, [email protected]
Message-ID: <[email protected]>
From: Avi Kivity <[email protected]>
(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 <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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(+)
--- 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;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3131,6 +3131,9 @@ 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) {
@@ -5956,6 +5959,11 @@ void kvm_arch_check_processor_compat(voi
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;
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -775,6 +775,13 @@ static inline bool kvm_vcpu_is_bsp(struc
{
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
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1720,6 +1720,10 @@ static int kvm_vm_ioctl_create_vcpu(stru
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;
Patches currently in stable-queue which might be from [email protected] are
queue-3.3/kvm-s390-do-store-status-after-handling-stop_on_stop-bit.patch
queue-3.3/kvm-nvmx-fix-erroneous-exception-bitmap-check.patch
queue-3.3/kvm-s390-sanitize-fpc-registers-for-kvm_set_fpu.patch
queue-3.3/kvm-x86-emulator-correctly-mask-pmc-index-bits-in-rdpmc-instruction-emulation.patch
queue-3.3/kvm-mmu_notifier-flush-tlbs-before-releasing-mmu_lock.patch
queue-3.3/kvm-vmx-fix-kvm_set_shared_msr-called-in-preemptible-context.patch
queue-3.3/kvm-vmx-vmx_set_cr0-expects-kvm-srcu-locked.patch
queue-3.3/kvm-ensure-all-vcpus-are-consistent-with-in-kernel-irqchip-settings.patch
queue-3.3/kvm-fix-write-protection-race-during-dirty-logging.patch
queue-3.3/kvm-lock-slots_lock-around-device-assignment.patch
queue-3.3/kvm-vmx-fix-delayed-load-of-shared-msrs.patch
--
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