From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5280606A31B for ; Mon, 26 Oct 2026 15:27:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=mRYpMAKu; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=GGcSxjh1 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=R+uyHs9ywIaM0i/9cYv3M9HNaFEltPzXJeKYyT3HeLQ=; b=mRYpMAKu/YnAXA R5gmEfTPPHGhJMMkkH7cmjcaKRZh+RKLKx0qXhnVPLde3UCaA7CNR5tDxh8/tu9Vb7GrSEZCz4RtM JCEwF6+dpDFDlwqHqbmQO+bqW0F5ktd0AZsMPzvYHiJNxFrS8ekCwx0QIs1cEdOwo4NxelIX9V76g mYPkWL8H7gTCiVjvAa3yVseSPefDu3loEvC9jxWe6dVb2KZfSu1QUGxhuJaKjIdQATAxCFFEiWVl6 4Mqincj53Xu08UdChl3bFYS6FSklnyxGCqAR5DAvPNoMqu3NeJzs1BL111FihHSQZG3pBBpA+x6Ue QELnFF8q5d3ncItFUYFg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLMbC-00000002l7M-2xX0; Mon, 26 Oct 2026 15:26:58 +0000 Received: from out-105.mta0.migadu.com ([2001:41d0:1004:224b::69] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLMb9-00000002l5x-0O1H for linux-arm-kernel@lists.infradead.org; Mon, 26 Oct 2026 15:26:56 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=HeX2/geBxz2dlu9U8tei1sYnbTS6/PpznfxzSmtORYY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793028413; v=1; x=1793633213; b=GGcSxjh1UC0cDCLlNJtR4af/Jfdu7XvwZolqns7vXAfIesqqt7TVSd7HO4oPf/+limgiRxdw DV0LNNzoxOi0BKQIM5w8+YSY284Gd3P5rFgj1nJFGGaXexmKRrjsNgRg/j8w9T9DVJeSk8kT8XY BkuAX/k18vmb9DWM3QRsX2pY= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 069beff3eddbe141; Mon, 26 Oct 2026 15:26:53 +0000 X-Mizu-Trace-ID: 069beff3eddbe141 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Raghavendra Rao Ananta , Eric Auger , Will Deacon , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] KVM: arm64: vgic-v4: Don't allocate vPEs when userspace clears nASSGIcap Date: Mon, 26 Oct 2026 15:26:39 +0000 Message-ID: <20261026152639.3926498-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261026152639.3926498-1-fuad.tabba@linux.dev> References: <20261026152639.3926498-1-fuad.tabba@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261026_082655_276539_09BC43A9 X-CRM114-Status: GOOD ( 10.28 ) X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Since commit c652887a92887 ("KVM: arm64: vgic-v3: Allow userspace to write GICD_TYPER2.nASSGIcap"), userspace can disable vPE allocation for a VM on a GICv4.1 host with vSGIs by clearing nASSGIcap before the vgic is initialised. vgic_init() then skips vgic_v4_init(), and kvm_vgic_dist_destroy() skips vgic_v4_teardown(). vgic_its_create() still calls vgic_v4_init() for an ITS created after the vgic is initialised, though, and vgic_v4_init() allocates the vPEs and requests a doorbell IRQ for each vCPU. Destroying the VM leaks them, and leaves each doorbell handler registered with a vCPU that's about to be freed. Rather than gate on vgic_supports_direct_irqs(), which reads has_its before vgic_its_create() sets it, check for a cleared nASSGIcap in vgic_v4_init(). Fixes: c652887a92887 ("KVM: arm64: vgic-v3: Allow userspace to write GICD_TYPER2.nASSGIcap") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba --- arch/arm64/kvm/vgic/vgic-v4.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c index a01de4de608a6..12a57921f6af3 100644 --- a/arch/arm64/kvm/vgic/vgic-v4.c +++ b/arch/arm64/kvm/vgic/vgic-v4.c @@ -251,6 +251,10 @@ int vgic_v4_init(struct kvm *kvm) if (!kvm_vgic_global_state.has_gicv4 || dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3) return 0; /* Nothing to see here... move along. */ + /* Userspace disabled vPE allocation by clearing nASSGIcap */ + if (system_supports_direct_sgis() && !vgic_supports_direct_sgis(kvm)) + return 0; + if (dist->its_vm.vpes) return 0; -- 2.47.3