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 4DDFC606A31A for ; Tue, 27 Oct 2026 22:53:25 +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=lfGn7B5U; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=LZyPwHfJ 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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; 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Tue, 27 Oct 2026 22:53:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793141592; bh=04q4u1JObS7tfcOZudjA/sgn19SAKGmJTGwcBE/ecfU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=LZyPwHfJlZOQqN7z+uCWJxqmk/WseCQmRIEWIZieJinlbPG0BxcFttrx6TYYvowhQ 4NpdFkbWNvv206a/5UWnPBgvabhA16HufdbzlxGZJVzw1kQm1SnPl0jeRbh1eBKgHi KC6K3mmbsR8uVx4AWC2hIkwKTYvddDDns2oMfHxQFbGIfdp+Nn0c5UhsronIwDbWjO WuOKZ2VE8KhJo3JinG7Hv+74NABgd7NkYgXG9k6fWTdez5HSaC4bCe0kt53br1xErF KpGBOYO1TXdEbxHCp8nAjYtUG5obptbAS/quITDHlJU1y2KIiSosxCIaplULhaidJ1 h1hiBEtteGksw== Date: Tue, 27 Oct 2026 15:53:11 -0700 From: Oliver Upton To: Fuad Tabba Cc: Marc Zyngier , 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: Re: [PATCH 2/2] KVM: arm64: vgic-v4: Don't allocate vPEs when userspace clears nASSGIcap Message-ID: References: <20261027073634.440288-1-fuad.tabba@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027073634.440288-1-fuad.tabba@linux.dev> 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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 On Tue, Oct 27, 2026 at 07:36:34AM +0000, Fuad Tabba wrote: > 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 ed236f083f0d7..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) > + 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); > > > Tested on the FVP (GICv4.0 and GICv4.1): KVM doesn't leak doorbells in > either patch's case, a GICv3 VM still gets its vPEs when the ITS is > created, and the reproducer above doesn't hit the WARN. Does that work > for you? If so, I'll send it as v2. Bugh... Thanks for de-crapifying my request. Yes, this works perfectly for me. Thanks, Oliver