From patchwork Thu May 19 15:37:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12855475 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 37F40C38A02 for ; Thu, 19 May 2022 15:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241547AbiESPm3 (ORCPT ); Thu, 19 May 2022 11:42:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241346AbiESPlq (ORCPT ); Thu, 19 May 2022 11:41:46 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF6993055D; Thu, 19 May 2022 08:41:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652974903; x=1684510903; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Ki9Xo5okkP+R+vbuSBF5h8cquKe/X5fGFu1xJg+soHM=; b=Bp88bnqZApLyEYz0zXgcEHEZIgrEryo+iARo0qHjSsBEw23tb74z+9YM aiL0w7L38eiaprQ9ICOKNEtEPaY3EUnrP2CBL1xY+grGQ+aGrUuiCTncd B9DB+nvviRW3bhHwx/doY0wSX5Yo7eSARtAzuwuwnaw2Zn7lFr/4fJlx+ WzKn77yHgUZE/Pqay7lagNUiG8nMPOqs+HpQSK+wVszJ+DkgTrfVxE5cL /VmDXoC91aogl81b4hBiZPcRLloylQH5wbUoIpvpqEW38KwKpYTjmJgZV 9DpPlsEH37V5j+V5Q/2sGtLjgYxe+FE0ZaaQXviAKm3XnSHOtwAD1eysn Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10352"; a="358655202" X-IronPort-AV: E=Sophos;i="5.91,237,1647327600"; d="scan'208";a="358655202" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2022 08:41:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,237,1647327600"; d="scan'208";a="598635316" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 19 May 2022 08:41:32 -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 , 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 Subject: [PATCH v6 5/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Date: Thu, 19 May 2022 23:37:10 +0800 Message-Id: <20220519153713.819591-6-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220519153713.819591-1-chao.p.peng@linux.intel.com> References: <20220519153713.819591-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@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 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. 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 b959445b64cc..2421c012278b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6341,6 +6341,28 @@ 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. + :: /* Fix the size of the union. */ diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 28cacd3656d4..6ca864be258f 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -294,6 +294,7 @@ 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_FAULT 36 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -518,6 +519,14 @@ struct kvm_run { unsigned long args[6]; unsigned long ret[2]; } riscv_sbi; + /* 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]; };