[3.16.y-ckt stable] Patch "arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources" has been added to staging queue

[Kamal Mostafa]

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

    arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources

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 3.19.8-ckt9.

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.
-Kamal

------

>From 669c12b945cc8e5bd2b4aa95d2f2f2d7f483ba3c Mon Sep 17 00:00:00 2001
From: Pavel Fedin <p.fedin at samsung.com>
Date: Wed, 5 Aug 2015 11:53:57 +0100
Subject: arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping
 resources

commit c2f58514cfb374d5368c9da945f1765cd48eb0da upstream.

Until b26e5fdac43c ("arm/arm64: KVM: introduce per-VM ops"),
kvm_vgic_map_resources() used to include a check on irqchip_in_kernel(),
and vgic_v2_map_resources() still has it.

But now vm_ops are not initialized until we call kvm_vgic_create().
Therefore kvm_vgic_map_resources() can being called without a VGIC,
and we die because vm_ops.map_resources is NULL.

Fixing this restores QEMU's kernel-irqchip=off option to a working state,
allowing to use GIC emulation in userspace.

Fixes: b26e5fdac43c ("arm/arm64: KVM: introduce per-VM ops")
Signed-off-by: Pavel Fedin <p.fedin at samsung.com>
[maz: reworked commit message]
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm/kvm/arm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 3ec9687..6391fa6 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -428,7 +428,7 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
 	 * Map the VGIC hardware resources before running a vcpu the first
 	 * time on this VM.
 	 */
-	if (unlikely(!vgic_ready(kvm))) {
+	if (unlikely(irqchip_in_kernel(kvm) && !vgic_ready(kvm))) {
 		ret = kvm_vgic_map_resources(kvm);
 		if (ret)
 			return ret;
--
1.9.1