From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12A03C433F5 for ; Fri, 25 Feb 2022 13:45:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240150AbiBYNp6 (ORCPT ); Fri, 25 Feb 2022 08:45:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234303AbiBYNp4 (ORCPT ); Fri, 25 Feb 2022 08:45:56 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 96FF0210D74 for ; Fri, 25 Feb 2022 05:45:24 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5B8D6106F; Fri, 25 Feb 2022 05:45:24 -0800 (PST) Received: from monolith.localdoman (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0EBA73F5A1; Fri, 25 Feb 2022 05:45:20 -0800 (PST) Date: Fri, 25 Feb 2022 13:45:45 +0000 From: Alexandru Elisei To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Andre Przywara , Christoffer Dall , Jintack Lim , Haibo Xu , Ganapatrao Kulkarni , Chase Conklin , "Russell King (Oracle)" , James Morse , Suzuki K Poulose , karl.heubaum@oracle.com, mihai.carabas@oracle.com, miguel.luis@oracle.com, kernel-team@android.com Subject: Re: [PATCH v6 42/64] KVM: arm64: nv: Fold guest's HCR_EL2 configuration into the host's Message-ID: References: <20220128121912.509006-1-maz@kernel.org> <20220128121912.509006-43-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220128121912.509006-43-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi, On Fri, Jan 28, 2022 at 12:18:50PM +0000, Marc Zyngier wrote: > When entering a L2 guest (nested virt enabled, but not in hypervisor > context), we need to honor the traps the L1 guest has asked enabled. > > For now, just OR the guest's HCR_EL2 into the host's. We may have to do > some filtering in the future though. Hmm... looks to me like the filtering is already implemented via the HCR_GUEST_NV_FILTER_FLAGS. Or am I misunderstanding something? > > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/hyp/vhe/switch.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c > index 0e164cc8e913..5e8eafac27c6 100644 > --- a/arch/arm64/kvm/hyp/vhe/switch.c > +++ b/arch/arm64/kvm/hyp/vhe/switch.c > @@ -78,6 +78,11 @@ static void __activate_traps(struct kvm_vcpu *vcpu) > if (!vcpu_el2_tge_is_set(vcpu)) > hcr |= HCR_AT | HCR_TTLB; > } > + } else if (vcpu_has_nv(vcpu)) { > + u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2); > + > + vhcr_el2 &= ~HCR_GUEST_NV_FILTER_FLAGS; > + hcr |= vhcr_el2; This makes sense, we only the guest to add extra traps on top of what KVM already traps, not remove traps from what KVM has configured. However, HCR_EL2.FIEN (bit 47) disables traps when the bit is 1. Shouldn't it be part of the HCR_GUEST_NV_FILTER_FLAGS? Thanks, Alex > } > > ___activate_traps(vcpu, hcr); > -- > 2.30.2 >