From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 255963451A7; Tue, 6 Jan 2026 18:13:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767723227; cv=none; b=lJ+dcnTwiay0DATrc7dx6CJO28LaS3FUA/gZMyktUuy9rABltNS8WND8nKMbyPRSEqR2ql1tyhyxoFWoxAASdZOt+M+CQbuwWLM27Y4msjWeYdWvmboRzxFEkDO3QNff77tuym2gRpSbCVoZh5rDa8dK/sjqP/pOtmlkn/u8iFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767723227; c=relaxed/simple; bh=X4ptDMl7qmbB25sxy/xvgjNdj3xGXDDDDxfwSx5avLo=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=ipoKPzLs+ssb9E4+nUzB0fsEI4EiL6V40X2Axyg+elZv0oiKDdsr9IqcXPtGmYcqQLtIEfajVq8CJLPsVRqILd14F9YWSKHXFx3xOqyDrP/fbl0B1my9ppOAYyCaTSekVlOtDxvO0E3gZdbGW0YTf1NlBQSc3M7BFYS5uc06Trs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Iv71P5Sj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Iv71P5Sj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7464C116C6; Tue, 6 Jan 2026 18:13:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767723226; bh=X4ptDMl7qmbB25sxy/xvgjNdj3xGXDDDDxfwSx5avLo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Iv71P5SjEa9HG3SWK6MLgREPnx6XzaExqiCoQHCuE74b/eQ/woqqcd0c417uTHbfr jfAv8ve6BC+YsWu90CgAw69+QIQarPf2QAgLDr0IUtNuhCugOKGrejNveimokTEh6x 2sySlBLxA9msyhr3cLCogu+s7lAnje8HZbbatbHwJHakGh07tqhFDmFeMsNzlEs+ug qRCNaKJMBJC2+CMTQObMTonpOUc8+33e1Va1xEZN8qBf0XOyieMk48N6z+66JtvTNr AxH0bb8+22Yl+8MavySgBYtW6xf/mxVi08abXuIQtfPMsGrvY3Pi6ES7k3Ctgqbp1F t0UKQ+TSC4Txg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vdBYu-0000000HQzg-15oA; Tue, 06 Jan 2026 18:13:44 +0000 Date: Tue, 06 Jan 2026 18:13:43 +0000 Message-ID: <86eco2mwx4.wl-maz@kernel.org> From: Marc Zyngier To: Sascha Bischoff Cc: "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "kvm@vger.kernel.org" , nd , "oliver.upton@linux.dev" , Joey Gouly , Suzuki Poulose , "yuzenghui@huawei.com" Subject: Re: [PATCH] KVM: arm64: gic: Check for vGICv3 when clearing TWI In-Reply-To: <20260106165154.3321753-1-sascha.bischoff@arm.com> References: <20260106165154.3321753-1-sascha.bischoff@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: Sascha.Bischoff@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, nd@arm.com, oliver.upton@linux.dev, Joey.Gouly@arm.com, Suzuki.Poulose@arm.com, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Tue, 06 Jan 2026 16:52:10 +0000, Sascha Bischoff wrote: > > Explicitly check for the vgic being v3 when disabling TWI. Failure to > check this can result in using the wrong view of the vgic CPU IF union > causing undesirable/unexpected behaviour. > > Signed-off-by: Sascha Bischoff > --- > arch/arm64/kvm/arm.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 4f80da0c0d1de..620a465248d1b 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -569,6 +569,7 @@ static bool kvm_vcpu_should_clear_twi(struct kvm_vcpu *vcpu) > return kvm_wfi_trap_policy == KVM_WFX_NOTRAP; > > return single_task_running() && > + vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3 && > (atomic_read(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count) || > vcpu->kvm->arch.vgic.nassgireq); > } Nice one. Wonder how many other similar cases we have... :-/ Reviewed-by: Marc Zyngier M. -- Without deviation from the norm, progress is not possible.