From patchwork Fri Dec 2 06:13:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 13062250 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 7F868C4167B for ; Fri, 2 Dec 2022 06:20:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232470AbiLBGUD (ORCPT ); Fri, 2 Dec 2022 01:20:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232382AbiLBGTj (ORCPT ); Fri, 2 Dec 2022 01:19:39 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49C23DFB46; Thu, 1 Dec 2022 22:19:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669961944; x=1701497944; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=DVQ0g3/rVdl/Yl3T+oMVV4ILn+xt6i5l+sFNLAIKp18=; b=Oqw9I8MqT8K0vpnzNiqn3UEeS0uqBLpw3FEHd8rr7xW1uYyXmk9/VRMa 2+8Ysc5JGluE1Ap6EfUWx9COL7k/yAWmMQFSl8+oAyvWltTumZxTtabaz JJe9Vt0OCUYlT8hwjs7/3faF+XxFMhkZpo0dsRQr2duQpegVoCqQ6jJOs 9qHQk09tfVzPpiXBjOx1OubrT3m0r9eZRmWuEtdbJjwKJiKslo/BzQs6h R5EiEZzFGnsNkEoXx0Y0P+7CSrRFjD/7vvqy4EHrZLJE3wPOCIgYdnxFp T3Qta44WmGh8JtZ5o+YZX68CrO0vGaaEBMLzGFbmcfP9sNgDK4E/NbZfg g==; X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="380170524" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="380170524" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2022 22:19:02 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="733698677" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="733698677" Received: from chaop.bj.intel.com ([10.240.193.75]) by FMSMGA003.fm.intel.com with ESMTP; 01 Dec 2022 22:18:51 -0800 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 , 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 , 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, wei.w.wang@intel.com Subject: [PATCH v10 4/9] KVM: Add KVM_EXIT_MEMORY_FAULT exit Date: Fri, 2 Dec 2022 14:13:42 +0800 Message-Id: <20221202061347.1070246-5-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> References: <20221202061347.1070246-1-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. 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 Reviewed-by: Fuad Tabba Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- Documentation/virt/kvm/api.rst | 22 ++++++++++++++++++++++ include/uapi/linux/kvm.h | 8 ++++++++ 2 files changed, 30 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 99352170c130..d9edb14ce30b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6634,6 +6634,28 @@ 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 (1ULL << 0) + __u64 flags; + __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 13bff963b8b0..c7e9d375a902 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. */ @@ -541,6 +542,13 @@ struct kvm_run { #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) __u32 flags; } notify; + /* KVM_EXIT_MEMORY_FAULT */ + struct { +#define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 0) + __u64 flags; + __u64 gpa; + __u64 size; + } memory; /* Fix the size of the union. */ char padding[256]; };