From patchwork Thu Jan 12 19:18:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13098710 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 5E3DBC678D7 for ; Thu, 12 Jan 2023 19:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240748AbjALT3P (ORCPT ); Thu, 12 Jan 2023 14:29:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239901AbjALT2B (ORCPT ); Thu, 12 Jan 2023 14:28:01 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BDC93C70B for ; Thu, 12 Jan 2023 11:22:04 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D8224B82016 for ; Thu, 12 Jan 2023 19:22:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C6CAC433EF; Thu, 12 Jan 2023 19:22:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673551321; bh=HsN037LfeuyfMRmeB8Br5r4HgPUnJHbRpc4tZpWUniw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fvBvpCWWZ2Em86efUN2bNzDiMtHm9oOGSbWYq6J/fDJ+DLj9mmDzraX2EMDx4rHt/ pzjOisYfsi8Zz37tMeNPpq0o710G+lBqXkXEHKniUqALDKVfZqRCSPpGNov05kKiBp wAbPbdOS889BQMoL6w+XKgQlqfq3TapYh2zqW8F4vPbo16bCBOOOVARMbuUz09lTXD f03WuCEICKhvMwCC2+Zo8++Votp63iqsUHq3dWl9oZ4bUvcWkfAEQNZeFcRum8wks9 CY5iui4aaKpR2eHu6oZTXa6FIam7Se6lNWvL2dxEs1okroAwZYmFU/GalPaML+IPJ7 zWDt2BI5mUyRA== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pG374-001IWu-TR; Thu, 12 Jan 2023 19:19:46 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandru Elisei , Andre Przywara , Chase Conklin , Christoffer Dall , Ganapatrao Kulkarni , Jintack Lim , Russell King , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v7 30/68] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization Date: Thu, 12 Jan 2023 19:18:49 +0000 Message-Id: <20230112191927.1814989-31-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230112191927.1814989-1-maz@kernel.org> References: <20230112191927.1814989-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, alexandru.elisei@arm.com, andre.przywara@arm.com, chase.conklin@arm.com, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, jintack@cs.columbia.edu, rmk+kernel@armlinux.org.uk, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, 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 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Jintack Lim We enable nested virtualization by setting the HCR NV and NV1 bit. When the virtual E2H bit is set, we can support EL2 register accesses via EL1 registers from the virtual EL2 by doing trap-and-emulate. A better alternative, however, is to allow the virtual EL2 to access EL2 register states without trap. This can be easily achieved by not traping EL1 registers since those registers already have EL2 register states. Signed-off-by: Jintack Lim Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_arm.h | 1 + arch/arm64/kvm/hyp/vhe/switch.c | 38 +++++++++++++++++++++++++++++--- 2 files changed, 36 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 8425ef64d31a..5a9df623af94 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -88,6 +88,7 @@ HCR_BSU_IS | HCR_FB | HCR_TACR | \ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \ HCR_FMO | HCR_IMO | HCR_PTW | HCR_TID3 ) +#define HCR_GUEST_NV_FILTER_FLAGS (HCR_ATA | HCR_API | HCR_APK | HCR_FIEN) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK | HCR_ATA) #define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 41385bb02d6b..36b50e315504 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -38,9 +38,41 @@ static void __activate_traps(struct kvm_vcpu *vcpu) u64 hcr = vcpu->arch.hcr_el2; u64 val; - /* Trap VM sysreg accesses if an EL2 guest is not using VHE. */ - if (vcpu_is_el2(vcpu) && !vcpu_el2_e2h_is_set(vcpu)) - hcr |= HCR_TVM | HCR_TRVM; + if (is_hyp_ctxt(vcpu)) { + hcr |= HCR_NV; + + if (!vcpu_el2_e2h_is_set(vcpu)) { + /* + * For a guest hypervisor on v8.0, trap and emulate + * the EL1 virtual memory control register accesses. + */ + hcr |= HCR_TVM | HCR_TRVM | HCR_NV1; + } else { + /* + * For a guest hypervisor on v8.1 (VHE), allow to + * access the EL1 virtual memory control registers + * natively. These accesses are to access EL2 register + * states. + * Note that we still need to respect the virtual + * HCR_EL2 state. + */ + u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2); + + vhcr_el2 &= ~HCR_GUEST_NV_FILTER_FLAGS; + + /* + * We already set TVM to handle set/way cache maint + * ops traps, this somewhat collides with the nested + * virt trapping for nVHE. So turn this off for now + * here, in the hope that VHE guests won't ever do this. + * TODO: find out whether it's worth to support both + * cases at the same time. + */ + hcr &= ~HCR_TVM; + + hcr |= vhcr_el2 & (HCR_TVM | HCR_TRVM); + } + } ___activate_traps(vcpu, hcr);