From patchwork Wed Jul 6 08:20:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12907537 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 0F4F6CCA480 for ; Wed, 6 Jul 2022 08:26:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232170AbiGFI0s (ORCPT ); Wed, 6 Jul 2022 04:26:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231142AbiGFI0X (ORCPT ); Wed, 6 Jul 2022 04:26:23 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7FFE24084; Wed, 6 Jul 2022 01:25:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657095942; x=1688631942; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FGkTJa97HOG1krLu0LkGFpeexUG5AtVix0TiuS9l5H4=; b=JTFReDBqmRN2ZKDrXwK0d5X/q5taymz7KHt11u+CKpTCiGLLXudlEi7L fvt2LN26Df7Ewb7PCoxnC5Po8hzkGdm+sFJOGIsXPabEs/ng51R3tQTW+ P1eqJbNq6VNohlO/bpy01pp8eu2xU42EOV7q+hzSUiHu9jv1HsYuDY2y3 TwQ1+D80Ndn2jL68M8UXyLzQ/aN3HUqHZe4/Om3m8MDtOGmJQokYHZlwS BJn/ByXk9Zb/d0/rNZf2k+9cn7GVUWvDkjNWP1xq5X1l3Dn99/iqbfzP+ gcoN1yJmhIie7PkGZVX23EvOM6XPTyqmn65NUKP/t+oOERlRNQx2LwdAq g==; X-IronPort-AV: E=McAfee;i="6400,9594,10399"; a="272467241" X-IronPort-AV: E=Sophos;i="5.92,249,1650956400"; d="scan'208";a="272467241" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2022 01:25:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,249,1650956400"; d="scan'208";a="567968196" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga006.jf.intel.com with ESMTP; 06 Jul 2022 01:25:29 -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, linux-kselftest@vger.kernel.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 Subject: [PATCH v7 10/14] KVM: Add KVM_EXIT_MEMORY_FAULT exit Date: Wed, 6 Jul 2022 16:20:12 +0800 Message-Id: <20220706082016.2603916-11-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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. After private memory is enabled, this new exit will be used for KVM to exit to userspace for shared memory <-> 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. * if the fault is due to a private memory access then causes a userspace exit for a shared->private conversion when the page is recognized as shared by KVM. * If the fault is due to a shared memory access then causes a userspace exit for a private->shared conversion when the page is recognized as private by KVM. Suggested-by: Sean Christopherson Co-developed-by: Yu Zhang Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- Documentation/virt/kvm/api.rst | 22 ++++++++++++++++++++++ include/uapi/linux/kvm.h | 9 +++++++++ 2 files changed, 31 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 4f27c973a952..5ecfc7fbe0ee 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6583,6 +6583,28 @@ 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 c467c69b7ad7..83c278f284dd 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -299,6 +299,7 @@ struct kvm_xen_exit { #define KVM_EXIT_XEN 34 #define KVM_EXIT_RISCV_SBI 35 #define KVM_EXIT_NOTIFY 36 +#define KVM_EXIT_MEMORY_FAULT 37 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -530,6 +531,14 @@ 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]; };