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 B834FC38A2D for ; Tue, 25 Oct 2022 15:19:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233156AbiJYPT0 (ORCPT ); Tue, 25 Oct 2022 11:19:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233174AbiJYPTF (ORCPT ); Tue, 25 Oct 2022 11:19:05 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD40818A01A; Tue, 25 Oct 2022 08:18:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666711139; x=1698247139; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ih/6HAJshbJt6TWBogTEZBcZrL2eIfbHydJCwgeirTw=; b=kFK9dAVMD1GARcs8kLVXHQANNi01S689U2idQCwQeiEI36zfxs0IRv7J kQoiCJqeURImcmONFBS8fXxM1YsLLna+ZFGi543IxWNbdjjcvwVsTWQEq 67jv7z4T4QV3LhUaK3IdNTdxvK4xiCx2nDgiUBgYl7YOisyBcjyQqj86N aA8gZ8V1kXjF0RIzvvMYQVdpdmNtmPEWPD0inbpv8v07lYtGmMU0IzPrP M6G/87cxqxKMx6tbd9OWv84b5CcTQm2pR7HD0sbNU1fjdMa5mBETnwJWg aotvT/TQtmQ/3SkMaUhnORzF7qNCMK0+p2Zv4NbieZOQj3Orm7NJZ6A4V g==; X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="307700547" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="307700547" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2022 08:18:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="736865566" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="736865566" Received: from chaop.bj.intel.com ([10.240.193.75]) by fmsmga002.fm.intel.com with ESMTP; 25 Oct 2022 08:18:47 -0700 From: Chao Peng To: 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 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 , tabba@google.com, Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: [PATCH v9 3/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Date: Tue, 25 Oct 2022 23:13:39 +0800 Message-Id: <20221025151344.3784230-4-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 perform 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 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; + +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 f1ae45c10c94..fa60b032a405 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]; }; -- 2.25.1