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[GIT,PULL,10/12] arm/arm64: KVM: Don't allow creating VCPUs after vgic_initialized

Message ID 1418643719-25966-11-git-send-email-christoffer.dall@linaro.org
State Accepted
Commit 716139df2517fbc3f2306dbe8eba0fa88dca0189
Headers show

Commit Message

Christoffer Dall Dec. 15, 2014, 11:41 a.m. UTC 
When the vgic initializes its internal state it does so based on the
number of VCPUs available at the time.  If we allow KVM to create more
VCPUs after the VGIC has been initialized, we are likely to error out in
unfortunate ways later, perform buffer overflows etc.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
 arch/arm/kvm/arm.c | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index c5a05f2..66f37c4 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -213,6 +213,11 @@  struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 	int err;
 	struct kvm_vcpu *vcpu;
 
+	if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) {
+		err = -EBUSY;
+		goto out;
+	}
+
 	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
 	if (!vcpu) {
 		err = -ENOMEM;