From patchwork Thu Sep 15 14:29:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12977462 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 EC58FECAAA1 for ; Thu, 15 Sep 2022 14:34:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7F0898D0002; Thu, 15 Sep 2022 10:34:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 777FD8D0001; Thu, 15 Sep 2022 10:34:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5F2488D0002; Thu, 15 Sep 2022 10:34:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 481288D0001 for ; Thu, 15 Sep 2022 10:34:39 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id BE3C71C6262 for ; Thu, 15 Sep 2022 14:34:35 +0000 (UTC) X-FDA: 79914565710.11.A0655C9 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf22.hostedemail.com (Postfix) with ESMTP id 04E03C00C2 for ; Thu, 15 Sep 2022 14:34:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663252474; x=1694788474; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=zh1uU9OfCds79z0Ds97NHO+IjadPr1HQahUg4D7PcaE=; b=IHzD76B6dpVd/ZPdBUMnMfUk/Uv1OVt/MZUpIMKi/LXdEvpzhIC/Xo+3 S5swdEB2nIjvD570dtu3IQDogyP74XQ6kcjqmbUyYhgSZCcI3KL9sk1Rt lh3AEc/Ey0ssam0ZLzC4h4R2fJMjmqevfXZZP7RolyWnvptelQHTE1LcQ x0D6XHHeOcCNzP7MzS6RwmJmqdrQSVTEUTvwIdlNy+OjC40k6AhJQ7zGB cAdgBIgQ7+s1iCfkyPziZqXtygJH6uaGdj6ebZJe1SVRpPIrB9+kJGr9Z 17HFo7lVVJg0JeqAjuwy2IU0WeFWeDDFxjPcaXEowgipOiNxDQmR6v+aY A==; X-IronPort-AV: E=McAfee;i="6500,9779,10470"; a="281759296" X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="281759296" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 07:34:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="945977002" Received: from chaop.bj.intel.com ([10.240.193.75]) by fmsmga005.fm.intel.com with ESMTP; 15 Sep 2022 07:34:22 -0700 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , 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 , Chao Peng , "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 , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: [PATCH v8 3/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Date: Thu, 15 Sep 2022 22:29:08 +0800 Message-Id: <20220915142913.2213336-4-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> References: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=IHzD76B6; spf=none (imf22.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663252474; a=rsa-sha256; cv=none; b=w9zllp0tu1Gnz1Z9C9uISeqLeDSSiMc4qlJ7TV0euvvB89sSwubhXXTzchro7+T8Y5qtJY wigP9BBlcZg8yJFbehk/DIuSUK8BWC1gVQxQCvOytsSoC6OYiVeY5aoN8rajmk6ko1RjJV TcYS+D38ANpH7cLwpEqOs9k5BH50DDM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663252474; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=X3whFcQy4DiYJehiz1E4F67fBFUtgX6WLcXgaPYTV90=; b=aPZHqm1dghbe0GtoHMM9X2HAAHIlQyMlptKZnNOHvyssx/0Vzyb+j2EdberxJjrzLQXJOD xsyakqButmhOpnztnCwZcOsCpMGF2YTXPJ8OHLa5j2vFvTnWZFpU9D7liS3M2EbflcD8KJ qbKGunkonkM0vZr7HoFb8daJZvitzLc= X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 04E03C00C2 Authentication-Results: imf22.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=IHzD76B6; spf=none (imf22.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Stat-Signature: q3hzpicgqioypb5ta8pi6sxa777aj7c5 X-HE-Tag: 1663252473-109822 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: This new KVM exit allows userspace to handle memory-related errors. It indicates an error happens in KVM at guest memory range [gpa, gpa+size). The flags includes additional information for userspace to handle the error. Currently bit 0 is defined as 'private memory' where '1' indicates error happens due to private memory access and '0' indicates error happens due to shared memory access. When private memory is enabled, this new exit will be used for KVM to exit to userspace for shared <-> private memory conversion in memory encryption usage. In such usage, typically there are two kind of memory conversions: - explicit conversion: happens when guest explicitly calls into KVM to map a range (as private or shared), KVM then exits to userspace to do the map/unmap operations. - implicit conversion: happens in KVM page fault handler where KVM exits to userspace for an implicit conversion when the page is in a different state than requested (private or shared). Suggested-by: Sean Christopherson Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- Documentation/virt/kvm/api.rst | 23 +++++++++++++++++++++++ include/uapi/linux/kvm.h | 9 +++++++++ 2 files changed, 32 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index c1fac1e9f820..1a6c003b2a0b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6638,6 +6638,29 @@ 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; + +If exit reason is KVM_EXIT_MEMORY_FAULT then it indicates that the VCPU has +encountered a memory error which is not handled by KVM kernel module and +userspace may choose to handle it. The 'flags' field indicates the memory +properties of the exit. + + - KVM_MEMORY_EXIT_FLAG_PRIVATE - indicates the memory error is caused by + private memory access when the bit is set otherwise the memory error is + caused by shared memory access when the bit is clear. + +'gpa' and 'size' indicate the memory range the error occurs at. The userspace +may handle the error and return to KVM to retry the previous memory access. + :: /* KVM_EXIT_NOTIFY */ diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 3ef462fb3b2a..0c8db7b7c138 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -300,6 +300,7 @@ struct kvm_xen_exit { #define KVM_EXIT_RISCV_SBI 35 #define KVM_EXIT_RISCV_CSR 36 #define KVM_EXIT_NOTIFY 37 +#define KVM_EXIT_MEMORY_FAULT 38 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -538,6 +539,14 @@ struct kvm_run { #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) __u32 flags; } notify; + /* KVM_EXIT_MEMORY_FAULT */ + struct { +#define KVM_MEMORY_EXIT_FLAG_PRIVATE (1 << 0) + __u32 flags; + __u32 padding; + __u64 gpa; + __u64 size; + } memory; /* Fix the size of the union. */ char padding[256]; };