From patchwork Thu Mar 10 14:09:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12776408 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 7557EC433F5 for ; Thu, 10 Mar 2022 14:10:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 179678D000B; Thu, 10 Mar 2022 09:10:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 129EE8D0001; Thu, 10 Mar 2022 09:10:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 018928D000B; Thu, 10 Mar 2022 09:10:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id E75A88D0001 for ; Thu, 10 Mar 2022 09:10:34 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A969C9CD5C for ; Thu, 10 Mar 2022 14:10:34 +0000 (UTC) X-FDA: 79228661988.20.D74EB72 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf30.hostedemail.com (Postfix) with ESMTP id 07F7A80018 for ; Thu, 10 Mar 2022 14:10:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646921434; x=1678457434; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=Z4vQdKuwJGnUEOHT5u0YKIBAyF/sX/jaF7InK/l4l/o=; b=ORB6pm1Tg5a2uHP7B9VIRJOuf2Oxa3uuMi7eYg2rw4VM0v3lLtf2WObn GWehlNF5LskzaY9jlpB5czE3cpxo87ZBS53S9jg110OiIT4LJweJX+jFq OtSemtQr0B2p7RiTh4iNQnl5mPmk7PySEYhb9KqNF0t420lidSoNtdGNo 8/yxH1uZSQGFvbCpiWtIEdnShRQHkTwImWz6kM04y9zmPu7m9i3J9yxx4 F3TfldieVFny1B0uXY10c8wZoYoDWswH/3rFnk2objaPwPes2WOfwriMc dvWVmY+LZ/TbpFRmBw/H3g/yyGg1q2gr3RozRn7Jrn/xcIZgSeHGgGoTM Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10281"; a="255448396" X-IronPort-AV: E=Sophos;i="5.90,170,1643702400"; d="scan'208";a="255448396" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2022 06:10:33 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,170,1643702400"; d="scan'208";a="554655053" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 10 Mar 2022 06:10:24 -0800 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, 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 , 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 Subject: [PATCH v5 07/13] KVM: Add KVM_EXIT_MEMORY_ERROR exit Date: Thu, 10 Mar 2022 22:09:05 +0800 Message-Id: <20220310140911.50924-8-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220310140911.50924-1-chao.p.peng@linux.intel.com> References: <20220310140911.50924-1-chao.p.peng@linux.intel.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 07F7A80018 X-Stat-Signature: q3hgwg5rads4ydrdusddd849yz65s6y6 Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=ORB6pm1T; spf=none (imf30.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.115) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=pass (policy=none) header.from=intel.com X-Rspam-User: X-HE-Tag: 1646921433-922676 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. 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 request when the page has not been allocated in the private memory backend. * If the fault is due to a shared memory access then causes a userspace exit for a private->shared conversion request when the page has already been allocated in the private memory backend. 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 f76ac598606c..bad550c2212b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6216,6 +6216,28 @@ 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_ERROR */ + 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_ERROR 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. + :: /* Fix the size of the union. */ diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a523d834efc8..9ad0c8aa0263 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -278,6 +278,7 @@ struct kvm_xen_exit { #define KVM_EXIT_X86_BUS_LOCK 33 #define KVM_EXIT_XEN 34 #define KVM_EXIT_RISCV_SBI 35 +#define KVM_EXIT_MEMORY_ERROR 36 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -495,6 +496,14 @@ struct kvm_run { unsigned long args[6]; unsigned long ret[2]; } riscv_sbi; + /* KVM_EXIT_MEMORY_ERROR */ + 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]; };