From patchwork Tue Jan 18 13:21:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12716362 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 2BD7AC43217 for ; Tue, 18 Jan 2022 13:23:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA23F6B0085; Tue, 18 Jan 2022 08:22:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B79B56B0087; Tue, 18 Jan 2022 08:22:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A688F6B0088; Tue, 18 Jan 2022 08:22:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 9763E6B0085 for ; Tue, 18 Jan 2022 08:22:59 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 5CFAB18179025 for ; Tue, 18 Jan 2022 13:22:59 +0000 (UTC) X-FDA: 79043473278.27.01BAD55 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf06.hostedemail.com (Postfix) with ESMTP id 92DBA180002 for ; Tue, 18 Jan 2022 13:22:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642512178; x=1674048178; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=Sxmzc3HCYf+A9G7nAq2yyNQIgWHQdtSxzJnS7/C1WdQ=; b=Vanp+WWyefhpwus9gg+3mfqWnTeLIEE2xL4Tvv3JswQBjuXnFefZoHM/ e7i0tl3H3pSfg6W4RSyP6RMg1kiRqx8j3dRUoucO6Qdq5LHg2dGBUMEDG LPwcMg7hNEzBK/Raa9zGV7xCX+EkoHeTfzhM88wlYKB4T5PXbJuX2HKfn wRMZMl+p05r0S6yijVF/Nx0xq+jzZDNSVklEmzFmauYd/ulei4JZpWmGm cMuUoJUytraUvWsvj20S5W0q/t/kK0apYRF12aC9BhyLFmsEErXSQWYh6 HAV6IScwarHYaTDM0GlNeSauUykuknvSixgOc8k+9xJxFtDK7tBnBlXKC Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10230"; a="244609437" X-IronPort-AV: E=Sophos;i="5.88,297,1635231600"; d="scan'208";a="244609437" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2022 05:22:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,297,1635231600"; d="scan'208";a="531791861" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 18 Jan 2022 05:22:49 -0800 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@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 , 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 v4 08/12] KVM: Use memfile_pfn_ops to obtain pfn for private pages Date: Tue, 18 Jan 2022 21:21:17 +0800 Message-Id: <20220118132121.31388-9-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220118132121.31388-1-chao.p.peng@linux.intel.com> References: <20220118132121.31388-1-chao.p.peng@linux.intel.com> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 92DBA180002 X-Stat-Signature: 7id8xf8jh1wznqctku5ze8sc47q1t39c Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Vanp+WWy; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf06.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=chao.p.peng@linux.intel.com X-HE-Tag: 1642512177-2228 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: Private pages are not mmap-ed into userspace so can not reply on get_user_pages() to obtain the pfn. Instead we add a memfile_pfn_ops pointer pfn_ops in each private memslot and use it to obtain the pfn for a gfn. To do that, KVM should convert the gfn to the offset into the fd and then call get_lock_pfn callback. Once KVM completes its job it should call put_unlock_pfn to unlock the pfn. Note the pfn(page) is locked between get_lock_pfn/put_unlock_pfn to ensure pfn is valid when KVM uses it to establish the mapping in the secondary MMU page table. The pfn_ops is initialized via memfile_register_notifier from the memory backing store that provided the private_fd. Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- arch/x86/kvm/Kconfig | 1 + include/linux/kvm_host.h | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index ebc8ce9ec917..5d5bebaad9e7 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -47,6 +47,7 @@ config KVM select SRCU select INTERVAL_TREE select HAVE_KVM_PM_NOTIFIER if PM + select MEMFILE_NOTIFIER help Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 26118a45f0bb..927e7f44a02a 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -42,6 +42,7 @@ #include #include +#include #ifndef KVM_MAX_VCPU_IDS #define KVM_MAX_VCPU_IDS KVM_MAX_VCPUS @@ -460,6 +461,7 @@ struct kvm_memory_slot { u16 as_id; struct file *private_file; loff_t private_offset; + struct memfile_pfn_ops *pfn_ops; }; static inline bool kvm_slot_is_private(const struct kvm_memory_slot *slot) @@ -810,6 +812,7 @@ static inline void kvm_irqfd_exit(void) { } #endif + int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, struct module *module); void kvm_exit(void); @@ -2103,4 +2106,34 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +#ifdef CONFIG_MEMFILE_NOTIFIER +static inline long kvm_memfile_get_pfn(struct kvm_memory_slot *slot, gfn_t gfn, + int *order) +{ + pgoff_t index = gfn - slot->base_gfn + + (slot->private_offset >> PAGE_SHIFT); + + return slot->pfn_ops->get_lock_pfn(file_inode(slot->private_file), + index, order); +} + +static inline void kvm_memfile_put_pfn(struct kvm_memory_slot *slot, + kvm_pfn_t pfn) +{ + slot->pfn_ops->put_unlock_pfn(pfn); +} + +#else +static inline long kvm_memfile_get_pfn(struct kvm_memory_slot *slot, gfn_t gfn, + int *order) +{ + return -1; +} + +static inline void kvm_memfile_put_pfn(struct kvm_memory_slot *slot, + kvm_pfn_t pfn) +{ +} +#endif /* CONFIG_MEMFILE_NOTIFIER */ + #endif