From patchwork Thu Mar 10 14:09:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12776406 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 B3440C433EF for ; Thu, 10 Mar 2022 14:10:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 524728D0009; Thu, 10 Mar 2022 09:10:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D2548D0001; Thu, 10 Mar 2022 09:10:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39B2A8D0009; Thu, 10 Mar 2022 09:10:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0200.hostedemail.com [216.40.44.200]) by kanga.kvack.org (Postfix) with ESMTP id 2DAE28D0001 for ; Thu, 10 Mar 2022 09:10:19 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E5AF09D262 for ; Thu, 10 Mar 2022 14:10:18 +0000 (UTC) X-FDA: 79228661316.26.C9C0E3F Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf09.hostedemail.com (Postfix) with ESMTP id 11479140017 for ; Thu, 10 Mar 2022 14:10:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646921418; x=1678457418; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=R9N/T0uA9Epd8O0DLQkw3YWNAAFsUHVjLA2F5YkEzAE=; b=EuwlRaypq/ks3zRUGaXN33ON8xP4gcZKD0IaMHr5BHan6vcCPzwqN37y ppd66xjUSqb/Zl7XPzOjK7cqNepWNvHnextgJrajP3DlP+LCMeA7tiEAi 6N9cflqDalrBYatCuPA6fCZdSIPo/3g+pXlpTLrzmWAwmFc/nm+MnBFdR QdegJ0LxaYXLgHbVJLpda+PE6zy+sExXiYgN2fVvER9rhqB2DjpSNIYDQ r6iIe6rOJXZ4qU/fBtG1qb8TIMsqkNpkF3Qe6gI62Lvq/HzQ5NhPMVAxF 0QDrdS4s9U2WFXp3vZzUY0DFEMjifArulfG1ei4NRFH1q892KnyUNbmwj A==; X-IronPort-AV: E=McAfee;i="6200,9189,10281"; a="341684795" X-IronPort-AV: E=Sophos;i="5.90,170,1643702400"; d="scan'208";a="341684795" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2022 06:10:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,170,1643702400"; d="scan'208";a="554654963" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 10 Mar 2022 06:10:08 -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 05/13] KVM: Extend the memslot to support fd-based private memory Date: Thu, 10 Mar 2022 22:09:03 +0800 Message-Id: <20220310140911.50924-6-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-Queue-Id: 11479140017 X-Stat-Signature: cn7fito63oe3kg9q1q93zfnmj153ug7c X-Rspam-User: Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=EuwlRayp; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf09.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspamd-Server: rspam03 X-HE-Tag: 1646921417-34940 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: Extend the memslot definition to provide fd-based private memory support by adding two new fields (private_fd/private_offset). The memslot then can maintain memory for both shared pages and private pages in a single memslot. Shared pages are provided by existing userspace_addr(hva) field and private pages are provided through the new private_fd/private_offset fields. Since there is no 'hva' concept anymore for private memory so we cannot rely on get_user_pages() to get a pfn, instead we use the newly added memfile_notifier to complete the same job. This new extension is indicated by a new flag KVM_MEM_PRIVATE. Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- Documentation/virt/kvm/api.rst | 37 +++++++++++++++++++++++++++------- include/linux/kvm_host.h | 7 +++++++ include/uapi/linux/kvm.h | 8 ++++++++ 3 files changed, 45 insertions(+), 7 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 3acbf4d263a5..f76ac598606c 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1307,7 +1307,7 @@ yet and must be cleared on entry. :Capability: KVM_CAP_USER_MEMORY :Architectures: all :Type: vm ioctl -:Parameters: struct kvm_userspace_memory_region (in) +:Parameters: struct kvm_userspace_memory_region(_ext) (in) :Returns: 0 on success, -1 on error :: @@ -1320,9 +1320,17 @@ yet and must be cleared on entry. __u64 userspace_addr; /* start of the userspace allocated memory */ }; + struct kvm_userspace_memory_region_ext { + struct kvm_userspace_memory_region region; + __u64 private_offset; + __u32 private_fd; + __u32 padding[5]; +}; + /* for kvm_memory_region::flags */ #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) #define KVM_MEM_READONLY (1UL << 1) + #define KVM_MEM_PRIVATE (1UL << 2) This ioctl allows the user to create, modify or delete a guest physical memory slot. Bits 0-15 of "slot" specify the slot id and this value @@ -1353,12 +1361,27 @@ It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr be identical. This allows large pages in the guest to be backed by large pages in the host. -The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and -KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of -writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to -use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, -to make a new slot read-only. In this case, writes to this memory will be -posted to userspace as KVM_EXIT_MMIO exits. +kvm_userspace_memory_region_ext includes all the kvm_userspace_memory_region +fields. It also includes additional fields for some specific features. See +below description of flags field for more information. It's recommended to use +kvm_userspace_memory_region_ext in new userspace code. + +The flags field supports below flags: + +- KVM_MEM_LOG_DIRTY_PAGES can be set to instruct KVM to keep track of writes to + memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to use it. + +- KVM_MEM_READONLY can be set, if KVM_CAP_READONLY_MEM capability allows it, to + make a new slot read-only. In this case, writes to this memory will be posted + to userspace as KVM_EXIT_MMIO exits. + +- KVM_MEM_PRIVATE can be set to indicate a new slot has private memory backed by + a file descirptor(fd) and the content of the private memory is invisible to + userspace. In this case, userspace should use private_fd/private_offset in + kvm_userspace_memory_region_ext to instruct KVM to provide private memory to + guest. Userspace should guarantee not to map the same pfn indicated by + private_fd/private_offset to different gfns with multiple memslots. Failed to + do this may result undefined behavior. When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of the memory region are automatically reflected into the guest. For example, an diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9536ffa0473b..3be8116079d4 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -563,8 +563,15 @@ struct kvm_memory_slot { u32 flags; short id; u16 as_id; + struct file *private_file; + loff_t private_offset; }; +static inline bool kvm_slot_is_private(const struct kvm_memory_slot *slot) +{ + return slot && (slot->flags & KVM_MEM_PRIVATE); +} + static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_slot *slot) { return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 91a6fe4e02c0..a523d834efc8 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -103,6 +103,13 @@ struct kvm_userspace_memory_region { __u64 userspace_addr; /* start of the userspace allocated memory */ }; +struct kvm_userspace_memory_region_ext { + struct kvm_userspace_memory_region region; + __u64 private_offset; + __u32 private_fd; + __u32 padding[5]; +}; + /* * The bit 0 ~ bit 15 of kvm_memory_region::flags are visible for userspace, * other bits are reserved for kvm internal use which are defined in @@ -110,6 +117,7 @@ struct kvm_userspace_memory_region { */ #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) #define KVM_MEM_READONLY (1UL << 1) +#define KVM_MEM_PRIVATE (1UL << 2) /* for KVM_IRQ_LINE */ struct kvm_irq_level {