From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AE9B482F2 for ; Tue, 29 Jul 2025 14:37:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753799857; cv=none; b=Tb6EwNBNgjo/S9IbP5RSc2njToZBGu1N1x3JgHfK5lr/FRcZF93CbGAdRSkHFhUE45KZ4QazfSbxtliNLGx2ag5Id0xPAD/kvLsjrnJ2FaKZKJ4T6+ECwPYVyR7ExO0RgdW/enzMJVHBkzHWvSAO+MyhseO//4r2Q8ZTCoxslFU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753799857; c=relaxed/simple; bh=WcDBo56fYFqGtT23Tt4aeeploWz/hK7E2/sMoK4Evsk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NgWGttKGP3YZ9wILMhmsa1MwuC8pRm/WyzUQmyDzZD3esVxWVSP1BpBfU8cJwq6uNO0iZHzU/yyuYWFrlrCicvWEYqSm92LI0MxuN2sYzH94vL+LXou92dAVhBCNQgfFZ95epxdB8Ry/wuUyrq5jfvg7yTUxlQHVxjTzS2Zz5Q4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=tgFHkjL1; arc=none smtp.client-ip=95.215.58.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="tgFHkjL1" Date: Tue, 29 Jul 2025 07:37:14 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1753799842; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=7SkkcDNglAXfu0FPaIefArcN3O7d7Q9M6mkwEnU1wYQ=; b=tgFHkjL1MUAkN7dMrvMKdcStfjJYcM4ebAA5sAdTDjfvIQEWiHLGWCSUsWvL0uV28S7XQ1 eIgJ5E1Qt1cTbsiu7xjOB+1Is3P/keuM343viJH8dUcSreCBvbbf71iiZ15IFVZ4/ZwNAn N5QIg5/aQUhNFUpZfk3nhd91z6higeU= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Raghavendra Rao Ananta Cc: Marc Zyngier , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH] KVM: arm64: Set/unset vGIC v4 forwarding if direct IRQs are supported Message-ID: References: <20250728223710.129440-1-rananta@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250728223710.129440-1-rananta@google.com> X-Migadu-Flow: FLOW_OUT Hi Raghu, Thanks for reporting this so quickly :) On Mon, Jul 28, 2025 at 10:37:10PM +0000, Raghavendra Rao Ananta wrote: > diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c > index e7e284d47a77..873a190bcff7 100644 > --- a/arch/arm64/kvm/vgic/vgic-v4.c > +++ b/arch/arm64/kvm/vgic/vgic-v4.c > @@ -433,7 +433,7 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, > unsigned long flags; > int ret = 0; > > - if (!vgic_supports_direct_msis(kvm)) > + if (!vgic_supports_direct_irqs(kvm)) > return 0; > > /* > @@ -533,7 +533,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int host_irq) > unsigned long flags; > int ret = 0; > > - if (!vgic_supports_direct_msis(kvm)) > + if (!vgic_supports_direct_irqs(kvm)) > return 0; I'm not sure this is what we want, since a precondition of actually doing vLPI injection is the guest having an ITS. Could you try the following? Thanks, Oliver diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index a3ef185209e9..70d50c77e5dc 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -50,6 +50,14 @@ bool vgic_has_its(struct kvm *kvm) bool vgic_supports_direct_msis(struct kvm *kvm) { + /* + * Deliberately conflate vLPI and vSGI support on GICv4.1 hardware, + * indirectly allowing userspace to control whether or not vPEs are + * allocated for the VM. + */ + if (system_supports_direct_sgis() && !vgic_supports_direct_sgis(kvm)) + return false; + return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm); } diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index 1384a04c0784..de1c1d3261c3 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -396,15 +396,7 @@ bool vgic_supports_direct_sgis(struct kvm *kvm); static inline bool vgic_supports_direct_irqs(struct kvm *kvm) { - /* - * Deliberately conflate vLPI and vSGI support on GICv4.1 hardware, - * indirectly allowing userspace to control whether or not vPEs are - * allocated for the VM. - */ - if (system_supports_direct_sgis()) - return vgic_supports_direct_sgis(kvm); - - return vgic_supports_direct_msis(kvm); + return vgic_supports_direct_msis(kvm) || vgic_supports_direct_sgis(kvm); } int vgic_v4_init(struct kvm *kvm);