* [PATCH v1] KVM: arm64: vgic: Reset in_kernel on private IRQ allocation failure
@ 2026-08-02 15:08 Fuad Tabba
2026-08-02 15:55 ` Marc Zyngier
0 siblings, 1 reply; 2+ messages in thread
From: Fuad Tabba @ 2026-08-02 15:08 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, kvmarm
Cc: stable, Sascha Bischoff, Jonathan Cameron, Joey Gouly,
Suzuki K Poulose, Zenghui Yu, Steffen Eiden, Catalin Marinas,
Will Deacon, Fuad Tabba, linux-arm-kernel, linux-kernel
kvm_vgic_create() sets vgic.in_kernel before allocating the per-vCPU
private IRQs, but the allocation-failure path resets only vgic_model and
leaves in_kernel set. As irqchip_in_kernel() is !!in_kernel, the VM is
left with an in-kernel irqchip but no model, and the -EEXIST guard at the
top of kvm_vgic_create() rejects every retry, so userspace cannot recover
from a transient -ENOMEM.
Reset in_kernel alongside vgic_model on the failure path.
Fixes: 9435c1e1431003 ("KVM: arm64: gic: Set vgic_model before initing private IRQs")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
arch/arm64/kvm/vgic/vgic-init.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 907057881b26a..fdac6e24762da 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -176,6 +176,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
}
kvm->arch.vgic.vgic_model = 0;
+ kvm->arch.vgic.in_kernel = false;
goto out_unlock;
}
base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff
--
2.39.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] KVM: arm64: vgic: Reset in_kernel on private IRQ allocation failure
2026-08-02 15:08 [PATCH v1] KVM: arm64: vgic: Reset in_kernel on private IRQ allocation failure Fuad Tabba
@ 2026-08-02 15:55 ` Marc Zyngier
0 siblings, 0 replies; 2+ messages in thread
From: Marc Zyngier @ 2026-08-02 15:55 UTC (permalink / raw)
To: Fuad Tabba
Cc: Oliver Upton, kvmarm, stable, Sascha Bischoff, Jonathan Cameron,
Joey Gouly, Suzuki K Poulose, Zenghui Yu, Steffen Eiden,
Catalin Marinas, Will Deacon, Fuad Tabba, linux-arm-kernel,
linux-kernel
On Sun, 02 Aug 2026 16:08:45 +0100,
Fuad Tabba <fuad.tabba@linux.dev> wrote:
>
> kvm_vgic_create() sets vgic.in_kernel before allocating the per-vCPU
> private IRQs, but the allocation-failure path resets only vgic_model and
> leaves in_kernel set. As irqchip_in_kernel() is !!in_kernel, the VM is
> left with an in-kernel irqchip but no model, and the -EEXIST guard at the
> top of kvm_vgic_create() rejects every retry, so userspace cannot recover
> from a transient -ENOMEM.
>
> Reset in_kernel alongside vgic_model on the failure path.
>
> Fixes: 9435c1e1431003 ("KVM: arm64: gic: Set vgic_model before initing private IRQs")
> Cc: stable@vger.kernel.org
> Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
> ---
> arch/arm64/kvm/vgic/vgic-init.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
> index 907057881b26a..fdac6e24762da 100644
> --- a/arch/arm64/kvm/vgic/vgic-init.c
> +++ b/arch/arm64/kvm/vgic/vgic-init.c
> @@ -176,6 +176,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
> }
>
> kvm->arch.vgic.vgic_model = 0;
> + kvm->arch.vgic.in_kernel = false;
> goto out_unlock;
> }
>
>
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Jazz isn't dead. It just smells funny.
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