[PATCH 4.2 035/134] arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources

From: Greg Kroah-Hartman
Date: Sat Sep 26 2015 - 18:16:54 EST

4.2-stable review patch. If anyone has any objections, please let me know.


From: Pavel Fedin <p.fedin@xxxxxxxxxxx>

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@xxxxxxxxxxx>
[maz: reworked commit message]
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/arm/kvm/arm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -449,7 +449,7 @@ static int kvm_vcpu_first_run_init(struc
* 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;

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