From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794064362; b=L9sRuGFZSScES0s4RxdXW7qwCxhPKmmtvl3W7rpBy+wjp3BBspfG9NwneO1ZK/5VUHtl T7FVYhfo0DTArFoLSOEiiGxRj3UtMq5udxwruM27bCuZu7yn7CTNwxGLES9FyrenDVn7v 2+vhk1EN4UjpLVjx4UBDvwL3HDEH+YYCkkXR0hclgoVDhi2bdpEJtzvg1Py7upNALp/WT +UVmqNdrqAt5pxDPSy+WNMxzq4XBOc9DQnfz4KrxVHAYxuQKJuUw7fbwiMjxpvlKANObJ XxfNddjktCicMmsNH3nWFwwDtHX0QxHSGlygGgozYlSoCSe/LATNzP2IVoT5ZKwpDdg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064362; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=154HHjylqzTzKLEXQd++3jvDjGLmjhAN4QHTnXlZBMo=; b=wdl/X1bD/XIsR+FuMZO9Qqmmz8cUs1qWvAHc0sV4xe0slStxaKRe4pd89QDft4BV5A5t FD5aiJdhf8h38QJSck5/CjWZXvHVT06Mz9eLTn0u9EX35aDsAgeLJp64FR5FecFZJ8jdf Pg5DpurD65ULxy8FSszN2Vy5vvgJjOlWQxoi6W47BZ9VWU4mJT4MHpHC+eh3lX4fmjqE0 THEY5lrLQykt6kE+5NU21j6qvcGvqr9EFiQ0/+3yCl8UwFzKpq4ZE8OnVxyR0HxQfmqb4 Obq3w9tVXzNEPPjLc2e0l8/hrg1Mj/vnTM7M37LISoKY81zTaC2girzV8w4UWRJ4mMA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=pQ5XQLOn; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C64F8606B894; Sat, 7 Nov 2026 15:12:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=pQ5XQLOn Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73CBC1F0089F; Sat, 7 Nov 2026 15:12:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064361; bh=154HHjylqzTzKLEXQd++3jvDjGLmjhAN4QHTnXlZBMo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pQ5XQLOnUZjkMZwxCO4+Uf4MOKMqgCWSABFhrvZaMZSX8fLFcP5lxkOqhhcxZHX4y slsJlPIyQCfz+hlnWBDnZocQFyWcCO2G0jQvbW6SHvl/fLISZ3vzU9wEpy45e1d2q6 txLIw5X5oftvzBFiK8o6sXANvpkwSdOgi8fKVADE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Karl Mehltretter , Marc Zyngier , Sasha Levin Subject: [PATCH 7.3 0443/1257] KVM: arm64: vgic-v3: Roll back assignments from the new region Date: Sat, 7 Nov 2026 08:45:39 -0500 Message-ID: <20261107134951.720335841@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Karl Mehltretter [ Upstream commit a32c01324eb494dda811912eb847b0e907cd7270 ] A failed REDIST_REGION write unregisters the redistributor iodevs of every vCPU processed before the failure. This includes vCPUs assigned to older regions. Their assignments remain cached, so a retry does not register the iodevs again. The vCPU whose registration fails has no assignment to roll back. For vCPUs processed earlier, limit rollback to those assigned to the new region. The region is removed on failure, so its free_index does not need restoring. Resetting assignments from older regions is unsafe because a vCPU can own one before kvm_for_each_vcpu() can see it. Rollback could then move free_index behind that live assignment. kvm_vgic_addr() holds slots_lock across the REDIST_REGION write. vCPU creation takes the same lock before assigning a redistributor. A concurrent vCPU cannot acquire an assignment from the new region before rollback completes. The lock also keeps rdreg valid across the config_lock drop required by MMIO-bus registration. Fixes: c011f4ea106b ("KVM: arm/arm64: Check vcpu redist base before registering an iodev") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Karl Mehltretter Link: https://patch.msgid.link/20260831081005.41346-3-kmehltretter@gmail.com [maz: moved helper into the sole caller] Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 8fb0a3eb3457d..5ab789accc9d4 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -846,7 +846,8 @@ void vgic_unregister_redist_iodev(struct kvm_vcpu *vcpu) kvm_io_bus_unregister_dev(vcpu->kvm, KVM_MMIO_BUS, &rd_dev->dev); } -static int vgic_register_all_redist_iodevs(struct kvm *kvm) +static int vgic_register_all_redist_iodevs(struct kvm *kvm, + struct vgic_redist_region *rdreg) { struct kvm_vcpu *vcpu; unsigned long c; @@ -866,7 +867,14 @@ static int vgic_register_all_redist_iodevs(struct kvm *kvm) for (i = 0; i < c; i++) { vcpu = kvm_get_vcpu(kvm, i); + if (vcpu->arch.vgic_cpu.rdreg != rdreg) + continue; + vgic_unregister_redist_iodev(vcpu); + + guard(mutex)(&vcpu->kvm->arch.config_lock); + vcpu->arch.vgic_cpu.rdreg = NULL; + vcpu->arch.vgic_cpu.rd_iodev.base_addr = VGIC_ADDR_UNDEF; } } @@ -975,10 +983,13 @@ void vgic_v3_free_redist_region(struct kvm *kvm, struct vgic_redist_region *rdre int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count) { + struct vgic_redist_region *rdreg; int ret; mutex_lock(&kvm->arch.config_lock); ret = vgic_v3_alloc_redist_region(kvm, index, addr, count); + if (!ret) + rdreg = vgic_v3_rdist_region_from_index(kvm, index); mutex_unlock(&kvm->arch.config_lock); if (ret) return ret; @@ -987,12 +998,9 @@ int vgic_v3_set_redist_base(struct kvm *kvm, u32 index, u64 addr, u32 count) * Register iodevs for each existing VCPU. Adding more VCPUs * afterwards will register the iodevs when needed. */ - ret = vgic_register_all_redist_iodevs(kvm); + ret = vgic_register_all_redist_iodevs(kvm, rdreg); if (ret) { - struct vgic_redist_region *rdreg; - mutex_lock(&kvm->arch.config_lock); - rdreg = vgic_v3_rdist_region_from_index(kvm, index); vgic_v3_free_redist_region(kvm, rdreg); mutex_unlock(&kvm->arch.config_lock); return ret; -- 2.53.0