From: Fuad Tabba <fuad.tabba@linux.dev>
To: Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oupton@kernel.org>,
	kvmarm@lists.linux.dev
Cc: stable@vger.kernel.org,
	Sascha Bischoff <Sascha.Bischoff@arm.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Joey Gouly <joey.gouly@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Steffen Eiden <seiden@linux.ibm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Fuad Tabba <tabba@google.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v1] KVM: arm64: vgic: Reset in_kernel on private IRQ allocation failure
Date: Sun,  2 Aug 2026 16:08:45 +0100
Message-Id: <20260802150845.3485757-1-fuad.tabba@linux.dev>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

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