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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77280C7618B for ; Wed, 24 Jul 2019 13:56:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 343F521926 for ; Wed, 24 Jul 2019 13:56:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=semihalf-com.20150623.gappssmtp.com header.i=@semihalf-com.20150623.gappssmtp.com header.b="NwZd6yqT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728185AbfGXN4i (ORCPT ); Wed, 24 Jul 2019 09:56:38 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:33205 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726422AbfGXN4i (ORCPT ); Wed, 24 Jul 2019 09:56:38 -0400 Received: by mail-lj1-f193.google.com with SMTP id h10so44619890ljg.0 for ; Wed, 24 Jul 2019 06:56:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=semihalf-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=54j3Rj1BXvYBjlVWokMkDuv8Oaagn4PllYy8yHElvpY=; b=NwZd6yqTUcteXpUZ0IGi33Soy/VPvyQzZ//L8nseZ2jkBr5cmxpituFU0uUN8X0zGy nwKaovJdV3763+hbbhbIArizrT86nxgiRscQKYUZiJ8WAr+3Y//LRvVDMXe9da6vmYSJ EU7GkkUGBUdRaT9bCIQkCHjyc5wH95o/ONyNMlbLoOz7XfRn9Q5YM8CRer0ziB+/ewXv TjClo7gCgUcE/jVq55UyQGOfZiYpEOnZuIckWX84vzCDOHpcBcXHIyx+pQkgruC55JTf 88883q5PF/LlRsx4mh6kR1p1MiJqzAHWpCd4otRMU64nY0tiA0z3XRDb9/OY+69RB0fe R/Gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=54j3Rj1BXvYBjlVWokMkDuv8Oaagn4PllYy8yHElvpY=; b=bWa9Ys8RGQL6oo5vkQqQo2czyrr5FMal4DUgxtJ2QXW2bBYVVJVvruFngtQpJyXPzo D1nfYRqwQICSFLdyj9gmFFdrpyAe+o2ox9v8RQYMvE3HkYf7KIYE2rYyfgOvUerZqIo7 oplp5Vs8BHsJzvpS2mpT4BmSKAv4cCSmw9vnj/d4d0FmIUtS5q52k0/6sFr5iCMR5t2X An+TXZTdw0RBlPku/HuoBCokHQjkUyBXkpkMM1CvQgc474CRM6TUyvMeHkdHD27kkaZS PcFDGSDxUneG2cN+5yD1RercyUKSZMd5Pa777ekiWFrsOOt6Xto+/mSAexyr/HUo0bmC 1f/g== X-Gm-Message-State: APjAAAUVWMW2w+2I1+/lzaqTK5rUBv9qjqKCk9r4zh+BHkdvJL4O2qjq QN8SCoQzT/0ilL4qPuRBROk= X-Google-Smtp-Source: APXvYqxO6yaPyMuq/MsVLMDvTjMxjWahFQFdCvdqAa57e+Yug9UF5euQajKuVL6dDDPv1F8dFEhYvw== X-Received: by 2002:a2e:8396:: with SMTP id x22mr44283342ljg.135.1563976595050; Wed, 24 Jul 2019 06:56:35 -0700 (PDT) Received: from [192.168.1.9] ([83.68.95.66]) by smtp.googlemail.com with ESMTPSA id r17sm8675692ljc.85.2019.07.24.06.56.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 06:56:34 -0700 (PDT) Subject: Re: [PATCH 43/59] KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2 To: Marc Zyngier , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Cc: Andre Przywara , Dave Martin References: <20190621093843.220980-1-marc.zyngier@arm.com> <20190621093843.220980-44-marc.zyngier@arm.com> <0411c636-adbd-98d0-5191-2b073daaf68e@semihalf.com> <327dfc0e-e7c9-0d18-2615-1db5b05121f4@arm.com> From: Tomasz Nowicki Message-ID: <5b4719fc-d189-41fa-cb64-9a731a80bf7e@semihalf.com> Date: Wed, 24 Jul 2019 15:56:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <327dfc0e-e7c9-0d18-2615-1db5b05121f4@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 24.07.2019 14:39, Marc Zyngier wrote: > On 24/07/2019 11:25, Tomasz Nowicki wrote: >> On 21.06.2019 11:38, Marc Zyngier wrote: >>> From: Jintack Lim >>> >>> When supporting nested virtualization a guest hypervisor executing AT >>> instructions must be trapped and emulated by the host hypervisor, >>> because untrapped AT instructions operating on S1E1 will use the wrong >>> translation regieme (the one used to emulate virtual EL2 in EL1 instead >>> of virtual EL1) and AT instructions operating on S12 will not work from >>> EL1. >>> >>> This patch does several things. >>> >>> 1. List and define all AT system instructions to emulate and document >>> the emulation design. >>> >>> 2. Implement AT instruction handling logic in EL2. This will be used to >>> emulate AT instructions executed in the virtual EL2. >>> >>> AT instruction emulation works by loading the proper processor >>> context, which depends on the trapped instruction and the virtual >>> HCR_EL2, to the EL1 virtual memory control registers and executing AT >>> instructions. Note that ctxt->hw_sys_regs is expected to have the >>> proper processor context before calling the handling >>> function(__kvm_at_insn) implemented in this patch. >>> >>> 4. Emulate AT S1E[01] instructions by issuing the same instructions in >>> EL2. We set the physical EL1 registers, NV and NV1 bits as described in >>> the AT instruction emulation overview. >>> >>> 5. Emulate AT A12E[01] instructions in two steps: First, do the stage-1 >>> translation by reusing the existing AT emulation functions. Second, do >>> the stage-2 translation by walking the guest hypervisor's stage-2 page >>> table in software. Record the translation result to PAR_EL1. >>> >>> 6. Emulate AT S1E2 instructions by issuing the corresponding S1E1 >>> instructions in EL2. We set the physical EL1 registers and the HCR_EL2 >>> register as described in the AT instruction emulation overview. >>> >>> 7. Forward system instruction traps to the virtual EL2 if the corresponding >>> virtual AT bit is set in the virtual HCR_EL2. >>> >>> [ Much logic above has been reworked by Marc Zyngier ] >>> >>> Signed-off-by: Jintack Lim >>> Signed-off-by: Marc Zyngier >>> Signed-off-by: Christoffer Dall >>> --- >>> arch/arm64/include/asm/kvm_arm.h | 2 + >>> arch/arm64/include/asm/kvm_asm.h | 2 + >>> arch/arm64/include/asm/sysreg.h | 17 +++ >>> arch/arm64/kvm/hyp/Makefile | 1 + >>> arch/arm64/kvm/hyp/at.c | 217 +++++++++++++++++++++++++++++++ >>> arch/arm64/kvm/hyp/switch.c | 13 +- >>> arch/arm64/kvm/sys_regs.c | 202 +++++++++++++++++++++++++++- >>> 7 files changed, 450 insertions(+), 4 deletions(-) >>> create mode 100644 arch/arm64/kvm/hyp/at.c >>> >> >> [...] >> >>> + >>> +void __kvm_at_s1e01(struct kvm_vcpu *vcpu, u32 op, u64 vaddr) >>> +{ >>> + struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt; >>> + struct mmu_config config; >>> + struct kvm_s2_mmu *mmu; >>> + >>> + /* >>> + * We can only get here when trapping from vEL2, so we're >>> + * translating a guest guest VA. >>> + * >>> + * FIXME: Obtaining the S2 MMU for a a guest guest is horribly >>> + * racy, and we may not find it. >>> + */ >>> + spin_lock(&vcpu->kvm->mmu_lock); >>> + >>> + mmu = lookup_s2_mmu(vcpu->kvm, >>> + vcpu_read_sys_reg(vcpu, VTTBR_EL2), >>> + vcpu_read_sys_reg(vcpu, HCR_EL2)); >>> + >>> + if (WARN_ON(!mmu)) >>> + goto out; >>> + >>> + /* We've trapped, so everything is live on the CPU. */ >>> + __mmu_config_save(&config); >>> + >>> + write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], SYS_TTBR0); >>> + write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], SYS_TTBR1); >>> + write_sysreg_el1(ctxt->sys_regs[TCR_EL1], SYS_TCR); >>> + write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1], SYS_SCTLR); >>> + write_sysreg(kvm_get_vttbr(mmu), vttbr_el2); >>> + /* FIXME: write S2 MMU VTCR_EL2 */ >>> + write_sysreg(config.hcr & ~HCR_TGE, hcr_el2); >> >> All below AT S1E* operations may initiate stage-1 PTW. And stage-1 table >> walk addresses are themselves subject to stage-2 translation. >> >> So should we enable stage-2 translation here by setting HCR_VM bit? > > Hopefully that's already the case, otherwise nothing works. Have you > verified that it is actually clear at this stage? Yes, HCR_EL2.VM is clear at this stage (cleared during guest exit when deactivating traps). The weird thing is that my Fastmodel is still working with HCR_EL2.VM=0 here and this path is being exercised. Thanks, Tomasz