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 0CF2CC46467 for ; Thu, 19 Jan 2023 22:55:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230287AbjASWz0 (ORCPT ); Thu, 19 Jan 2023 17:55:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229807AbjASWyd (ORCPT ); Thu, 19 Jan 2023 17:54:33 -0500 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 459635895D; Thu, 19 Jan 2023 14:37:07 -0800 (PST) Received: by mail-pg1-x52d.google.com with SMTP id f3so2768049pgc.2; Thu, 19 Jan 2023 14:37:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=c3/xglDrs4GgAM40Pjq1vzK1v2T7qf4JcCCRFWl6k4g=; b=NSYj639Mp9v5ap+wI0hCjvD0/JJIjDFxjIAk8s0W6QQZeGagLHTMYL5/dvvI2DPi4B +aGueObJ+RXaUVDn4NiXYFIhEcPYWxInkxzarthRsu1sZZ256/vMx7XvGmJtSYSWRLwB vl6fpplWJgAyhnKrjElYHYhD8OeiwcbmHLjIG5BiksGBX7KJzcLCywEenDObbw+Mxjwr pmu+l0l6CF6xX7jvLuX0TRIXSYOrvw5purr8S55V7TS8hL4NzHy8DcBRiXHfgymzDvFg PvZjALLBOjVmU5MNA64b0nuXlR2yYuFwQaHv+ETJElDhkdksrjTql7nEvp7HQxv7QCn3 HOLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=c3/xglDrs4GgAM40Pjq1vzK1v2T7qf4JcCCRFWl6k4g=; b=OpVuXW90GREJ8IPsBgaqU3tmELFOp4W+5eWlo+Q4wj0EQvohSimiv5iIP/nbKMBSDl +QgbbhwKsf2aXFQ+yWDH62NAvqLscYAkolUtMrSzIA+U8gZJ3CBuYgUlDQVWFOkgHmQm Z8EB1vbArrSTFv/3geeyzgVVJQ67U1Z3wslOnP0+oDDO5qU//mfNbAJ9104Y7HN7IIP+ zcjXcxunpwpwa/kJ4MoteHh2xf45+xrYrP9IfH9oS9j3rLCGFMEXeWZOOSk+p1x815Ry SsGhayfVldf9dr8TwS/QcO2bs5T/IS/yy54lYdPsy4KkftCwkmPe2h5Bm0tlrKBTZcL2 2Ilg== X-Gm-Message-State: AFqh2ko9jBOMzyZ/8bInYMczvJo1WTEnXDMpYXwlreoiix5J3ddKEY5O YiIgHEDFbkTDmlDqffsrRII= X-Google-Smtp-Source: AMrXdXtheeUgW/ehdT20D8crA3E+xLX19dRj8kq2j9cAtxWEF6/jTGrekTIsjKUTNo8D+nlbVHnJHA== X-Received: by 2002:a62:ab0b:0:b0:58b:46c9:a6b1 with SMTP id p11-20020a62ab0b000000b0058b46c9a6b1mr13080521pff.33.1674167826597; Thu, 19 Jan 2023 14:37:06 -0800 (PST) Received: from localhost ([192.55.54.55]) by smtp.gmail.com with ESMTPSA id c202-20020a621cd3000000b0058dc1d54db1sm6563910pfc.206.2023.01.19.14.37.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Jan 2023 14:37:05 -0800 (PST) Date: Thu, 19 Jan 2023 14:37:04 -0800 From: Isaku Yamahata To: Sean Christopherson Cc: Isaku Yamahata , Chao Peng , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , tabba@google.com, Michael Roth , mhocko@suse.com, wei.w.wang@intel.com Subject: Re: [PATCH v10 0/9] KVM: mm: fd-based approach for supporting KVM Message-ID: <20230119223704.GD2976263@ls.amr.corp.intel.com> References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> <20230119111308.GC2976263@ls.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2023 at 03:25:08PM +0000, Sean Christopherson wrote: > On Thu, Jan 19, 2023, Isaku Yamahata wrote: > > On Sat, Jan 14, 2023 at 12:37:59AM +0000, > > Sean Christopherson wrote: > > > > > On Fri, Dec 02, 2022, Chao Peng wrote: > > > > This patch series implements KVM guest private memory for confidential > > > > computing scenarios like Intel TDX[1]. If a TDX host accesses > > > > TDX-protected guest memory, machine check can happen which can further > > > > crash the running host system, this is terrible for multi-tenant > > > > configurations. The host accesses include those from KVM userspace like > > > > QEMU. This series addresses KVM userspace induced crash by introducing > > > > new mm and KVM interfaces so KVM userspace can still manage guest memory > > > > via a fd-based approach, but it can never access the guest memory > > > > content. > > > > > > > > The patch series touches both core mm and KVM code. I appreciate > > > > Andrew/Hugh and Paolo/Sean can review and pick these patches. Any other > > > > reviews are always welcome. > > > > - 01: mm change, target for mm tree > > > > - 02-09: KVM change, target for KVM tree > > > > > > A version with all of my feedback, plus reworked versions of Vishal's selftest, > > > is available here: > > > > > > git@github.com:sean-jc/linux.git x86/upm_base_support > > > > > > It compiles and passes the selftest, but it's otherwise barely tested. There are > > > a few todos (2 I think?) and many of the commits need changelogs, i.e. it's still > > > a WIP. > > > > > > As for next steps, can you (handwaving all of the TDX folks) take a look at what > > > I pushed and see if there's anything horrifically broken, and that it still works > > > for TDX? > > > > > > Fuad (and pKVM folks) same ask for you with respect to pKVM. Absolutely no rush > > > (and I mean that). > > > > > > On my side, the two things on my mind are (a) tests and (b) downstream dependencies > > > (SEV and TDX). For tests, I want to build a lists of tests that are required for > > > merging so that the criteria for merging are clear, and so that if the list is large > > > (haven't thought much yet), the work of writing and running tests can be distributed. > > > > > > Regarding downstream dependencies, before this lands, I want to pull in all the > > > TDX and SNP series and see how everything fits together. Specifically, I want to > > > make sure that we don't end up with a uAPI that necessitates ugly code, and that we > > > don't miss an opportunity to make things simpler. The patches in the SNP series to > > > add "legacy" SEV support for UPM in particular made me slightly rethink some minor > > > details. Nothing remotely major, but something that needs attention since it'll > > > be uAPI. > > > > Although I'm still debuging with TDX KVM, I needed the following. > > kvm_faultin_pfn() is called without mmu_lock held. the race to change > > private/shared is handled by mmu_seq. Maybe dedicated function only for > > kvm_faultin_pfn(). > > Gah, you're not on the other thread where this was discussed[*]. Simply deleting > the lockdep assertion is safe, for guest types that rely on the attributes to > define shared vs. private, KVM rechecks the attributes under the protection of > mmu_seq. > > I'll get a fixed version pushed out today. > > [*] https://lore.kernel.org/all/Y8gpl+LwSuSgBFks@google.com Now I have tdx kvm working. I've uploaded at the followings. It's rebased to v6.2-rc3. git@github.com:yamahata/linux.git tdx/upm git@github.com:yamahata/qemu.git tdx/upm kvm_mmu_do_page_fault() needs the following change. kvm_mem_is_private() queries mem_attr_array. kvm_faultin_pfn() also uses kvm_mem_is_private(). So the shared-private check in kvm_faultin_pfn() doesn't make sense. This change would belong to TDX KVM patches, though. diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index 72b0da8e27e0..f45ac438bbf4 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -430,7 +430,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, .max_level = vcpu->kvm->arch.tdp_max_page_level, .req_level = PG_LEVEL_4K, .goal_level = PG_LEVEL_4K, - .is_private = kvm_mem_is_private(vcpu->kvm, cr2_or_gpa >> PAGE_SHIFT), + .is_private = kvm_is_private_gpa(vcpu->kvm, cr2_or_gpa), }; int r; -- Isaku Yamahata