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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A65E4C4332F for ; Thu, 17 Nov 2022 13:47:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F2B856B0075; Thu, 17 Nov 2022 08:47:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EDBDA6B0078; Thu, 17 Nov 2022 08:47:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D7CD06B007B; Thu, 17 Nov 2022 08:47:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id C7AA76B0075 for ; Thu, 17 Nov 2022 08:47:27 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 6A85F12112F for ; Thu, 17 Nov 2022 13:47:27 +0000 (UTC) X-FDA: 80143061334.26.AA6B6C7 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf30.hostedemail.com (Postfix) with ESMTP id 8F49D80015 for ; Thu, 17 Nov 2022 13:47:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668692846; x=1700228846; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=Q9f7oXH6jx2XN9/kuSzGlUsyVFF0nM+veoTgLTKHR8Y=; b=eKkNbD8KPTr5qftFr1/Sd1IsYWCRB1dOMk33A89syddXI/k3W+1c0mJV 2tuT4LIP8GXcE8zGEDBnGVqwxr/90xr2YmRUTObu2/PM9pVVnUNmgJfOc //oOq4s2JH5buxGMLkVzXJvVkIMFKEo5egllP6JZnrTQbtLr6ntG3vYsp 7QqoYFHEbrFt5lMzHKXlHNkPOzoq3UGTO77y28TVVMYXHpW8vMjgiEeeH IXpkQeDHqvsYzOIjc3SXXgW0Kt9HqKe3VT6Kt9uTJtkOtcYfcA/3+9IeN itHnjAa+dtvMFC6DnbxOTXE2icUjfL05SAmn/LNoHXR0hKanA09jA4aZ3 A==; X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="310482574" X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="310482574" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Nov 2022 05:47:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="670927116" X-IronPort-AV: E=Sophos;i="5.96,171,1665471600"; d="scan'208";a="670927116" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.193.75]) by orsmga008.jf.intel.com with ESMTP; 17 Nov 2022 05:47:14 -0800 Date: Thu, 17 Nov 2022 21:42:50 +0800 From: Chao Peng To: Sean Christopherson Cc: Andy Lutomirski , kvm list , Linux Kernel Mailing List , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, Linux API , 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 , the arch/x86 maintainers , "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" , "Nakajima, Jun" , Dave Hansen , Andi Kleen , David Hildenbrand , aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Fuad Tabba , Michael Roth , Michal Hocko , Muchun Song , Wei W Wang Subject: Re: [PATCH v9 3/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Message-ID: <20221117134250.GC422408@chaop.bj.intel.com> Reply-To: Chao Peng References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> <20221025151344.3784230-4-chao.p.peng@linux.intel.com> <2e252f4f-7d45-42ac-a88f-fa8045fe3748@app.fastmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668692847; h=from:from:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/vHVefLIG5ravCWe/RmmCzG+cR9Rgbcqm12blxIpWaE=; b=8gEqUL8hScKTxAFYJ7GQEffkJ5BQLTwQ52C0aSz9Y4jFqBxRUKA0tAp/0+VEnaIzgnI8tv 9LxtdmPpNnpMn1GwjB9z/ylt8tudz7s3b3WaP7V3p1yGzKJsgahHLMywwggTrcwq2EyJIU tlOdf28a3JnyGleBdvp3lXYqsYrV5c4= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=eKkNbD8K; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf30.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.93) smtp.mailfrom=chao.p.peng@linux.intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668692847; a=rsa-sha256; cv=none; b=bDOi/5ilsRLEr8H2WrL/onCoX0aSErKpX2U+S0OjsY2ddEAQ1uokdbBaALc7ggF7QKZWGe wKjZ/YFb0cwgsUwq8pNGT4zaX1ZnDpazyy7725SZ00AOBYJA/FXH1Kb9C9iDj3/2HiVpW0 GYp9lys+Rkvx1Mxhgt0SWfxUnmcbMds= X-Rspam-User: X-Stat-Signature: b9xe3636qpb7yymkm8r7n43s75bwgwy3 X-Rspamd-Queue-Id: 8F49D80015 Authentication-Results: imf30.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=eKkNbD8K; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf30.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.93) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspamd-Server: rspam07 X-HE-Tag: 1668692846-665363 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Nov 16, 2022 at 06:48:43PM +0000, Sean Christopherson wrote: > On Wed, Nov 16, 2022, Andy Lutomirski wrote: > > > > > > On Tue, Oct 25, 2022, at 8:13 AM, Chao Peng wrote: > > > diff --git a/Documentation/virt/kvm/api.rst > > > b/Documentation/virt/kvm/api.rst > > > index f3fa75649a78..975688912b8c 100644 > > > --- a/Documentation/virt/kvm/api.rst > > > +++ b/Documentation/virt/kvm/api.rst > > > @@ -6537,6 +6537,29 @@ array field represents return values. The > > > userspace should update the return > > > values of SBI call before resuming the VCPU. For more details on > > > RISC-V SBI > > > spec refer, https://github.com/riscv/riscv-sbi-doc. > > > > > > +:: > > > + > > > + /* KVM_EXIT_MEMORY_FAULT */ > > > + struct { > > > + #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1 << 0) > > > + __u32 flags; > > > + __u32 padding; > > > + __u64 gpa; > > > + __u64 size; > > > + } memory; > > > + > > > > Would it make sense to also have a field for the access type (read, write, > > execute, etc)? I realize that shared <-> private conversion doesn't strictly > > need this, but it seems like it could be useful for logging failures and also > > for avoiding a second immediate fault if the type gets converted but doesn't > > have the right protection yet. > > I don't think a separate field is necessary, that info can be conveyed via flags. > Though maybe we should go straight to a u64 for flags. Yeah, I can do that. > Hmm, and maybe avoid bits > 0-3 so that if/when RWX info is conveyed the flags can align with > PROT_{READ,WRITE,EXEC} and the EPT flags, e.g. You mean avoiding bits 0-2, right, bit3 is not so special and can be used for KVM_MEMORY_EXIT_FLAG_PRIVATE. Chao > > KVM_MEMORY_EXIT_FLAG_READ (1 << 0) > KVM_MEMORY_EXIT_FLAG_WRITE (1 << 1) > KVM_MEMORY_EXIT_FLAG_EXECUTE (1 << 2) > > > (Obviously, if this were changed, KVM would need the ability to report that > > it doesn't actually know the mode.) > > > > --Andy