[3.16.y-ckt stable] Patch "arm/arm64: KVM: Don't allow creating VCPUs after vgic_initialized" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    arm/arm64: KVM: Don't allow creating VCPUs after vgic_initialized

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 3376ce3c85aaa7725980a1ae32548ebe15c57eb9 Mon Sep 17 00:00:00 2001
From: Christoffer Dall <christoffer.dall at linaro.org>
Date: Tue, 9 Dec 2014 14:33:45 +0100
Subject: arm/arm64: KVM: Don't allow creating VCPUs after vgic_initialized

commit 716139df2517fbc3f2306dbe8eba0fa88dca0189 upstream.

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 at arm.com>
Reviewed-by: Eric Auger <eric.auger at linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm/kvm/arm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 0fb257c84366..877e7cadc538 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -221,6 +221,11 @@ 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;