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 0DD4D606A31A for ; Wed, 28 Oct 2026 10:13:50 +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=Ey1jnJ5S; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=j64q8qUb 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=5NABG2AiXntzQQhgrbFs5uOv8MiJIKrNTvyQWAjpfGM=; b=Ey1jnJ5Sb7CmVp pmvlcPNUcbNVRvtnQebs6uWVtoBYOvpQ3jRyoO9G7C/JrOQ1BI6wRl1f5cohkOUq/RifxkrLVgl7s 9GW5svNusjTq3hZSpxRP9AasPUJkajaQpzEUS2w2P3CIE1mB0R0m9j5oyc9Rl73a5HuxzpMfQSpRF IYYlKSi9Hv1rny/uNX9xIZ2KadMJCyizlhgLmTaG5HEzvPknGvWYiCfmknaZUax1f0G0/ncOiewNS khSebB+B68Td7NRz3Xa7zwMVLWJVhxbiZ7k4L5BvmG5BCpyancLB3Uh9F/OOaehBSuuXMjJHr22Xt Ib++aubKzdxH8JoJmryw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM0f9-00000006jaV-28eJ; Wed, 28 Oct 2026 10:13:43 +0000 Received: from out-205.mta1.migadu.com ([95.215.58.205] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xM0f2-00000006jXy-1iO6 for linux-arm-kernel@lists.infradead.org; Wed, 28 Oct 2026 10:13:37 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=kg3kdJ38Ft3AD46ZxOYLXC0C0yujn9suVYw9Z8g/U9Y=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793182414; v=1; x=1793787214; b=j64q8qUbnIImZVnnR94EjYfCqijHtVApq4tBd9c7UecgpowHQdKQ0YVAzh/473sxqNm+N3Eb RgxM1RTMOfqkd17Ph5ETyzwZ4fygmIS+uFy56vYlIutGl2koa4ScNG4rNMHmaUpq29QVVBRNvmq j1kUINqeL81wTs9XPrBqc1Zs= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 8e770c70f83dabeb; Wed, 28 Oct 2026 10:13:34 +0000 X-Mizu-Trace-ID: 8e770c70f83dabeb 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 , Sascha Bischoff , Will Deacon , Fuad Tabba , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] KVM: arm64: vgic-v4: Don't allocate vPEs when userspace clears nASSGIcap Date: Wed, 28 Oct 2026 10:13:18 +0000 Message-ID: <20261028101318.2170928-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261028101318.2170928-1-fuad.tabba@linux.dev> References: <20261028101318.2170928-1-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-20261028_031336_610784_6CA0272E X-CRM114-Status: GOOD ( 12.39 ) 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=-18.9 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. Move the part of vgic_supports_direct_msis() that doesn't depend on the ITS into vgic_supports_vpes(), together with vgic_v4_init()'s GICv3 check. Gate vgic_v4_init() on it rather than on vgic_supports_direct_irqs(), which reads has_its before vgic_its_create() sets it. vgic_supports_direct_msis() returns what it did before, since vgic_has_its() is already false for a non-GICv3 VM. Fixes: c652887a92887 ("KVM: arm64: vgic-v3: Allow userspace to write GICD_TYPER2.nASSGIcap") Suggested-by: Oliver Upton Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba --- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 9 +++++++-- arch/arm64/kvm/vgic/vgic-v4.c | 2 +- arch/arm64/kvm/vgic/vgic.h | 1 + 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 5913a20d83019..a60697238a7a7 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -48,7 +48,7 @@ bool vgic_has_its(struct kvm *kvm) return dist->has_its; } -bool vgic_supports_direct_msis(struct kvm *kvm) +bool vgic_supports_vpes(struct kvm *kvm) { /* * Deliberately conflate vLPI and vSGI support on GICv4.1 hardware, @@ -58,7 +58,12 @@ bool vgic_supports_direct_msis(struct kvm *kvm) if (system_supports_direct_sgis() && !vgic_supports_direct_sgis(kvm)) return false; - return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm); + return kvm_vgic_global_state.has_gicv4 && vgic_is_v3(kvm); +} + +bool vgic_supports_direct_msis(struct kvm *kvm) +{ + return vgic_supports_vpes(kvm) && vgic_has_its(kvm); } bool system_supports_direct_sgis(void) diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c index a01de4de608a6..0a4b9a74425b4 100644 --- a/arch/arm64/kvm/vgic/vgic-v4.c +++ b/arch/arm64/kvm/vgic/vgic-v4.c @@ -248,7 +248,7 @@ int vgic_v4_init(struct kvm *kvm) lockdep_assert_held(&kvm->arch.config_lock); - if (!kvm_vgic_global_state.has_gicv4 || dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3) + if (!vgic_supports_vpes(kvm)) return 0; /* Nothing to see here... move along. */ if (dist->its_vm.vpes) diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index b71d486ae5145..7fc29a395a7db 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -500,6 +500,7 @@ static inline bool vgic_host_has_gicv5(void) } bool system_supports_direct_sgis(void); +bool vgic_supports_vpes(struct kvm *kvm); bool vgic_supports_direct_msis(struct kvm *kvm); bool vgic_supports_direct_sgis(struct kvm *kvm); -- 2.47.3