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: 12716373 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 0464AC433F5 for ; Tue, 18 Jan 2022 13:23:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243229AbiARNXA (ORCPT ); Tue, 18 Jan 2022 08:23:00 -0500 Received: from mga04.intel.com ([192.55.52.120]:18818 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242933AbiARNW5 (ORCPT ); Tue, 18 Jan 2022 08:22:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642512177; x=1674048177; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=Sxmzc3HCYf+A9G7nAq2yyNQIgWHQdtSxzJnS7/C1WdQ=; b=hL2+HxVZricn2zr/dzQ8GZAwbTkDqoyCW53TXzoIePdEQiKN4PtiJpGR /p80VcPvt2HkDJdtsqIZ0JQvWqPRY3Au6VIabRQx+n4yM1UFiFBLBFhbq 8OPryc9+ozWA5IfPDuwWaanPfLjJFWc/mYSDzZo4Z5LubpKyEU9hwmuPd I5o+tlR/qdzTb7wvBzYhZJCbi/ZWD+FG8tI8P83g+97jMo0cxfubjofcy quVx2DtH8YnTMwFoD50ebNg6uIQ6nHU+AkD0V6Y6yLfWBZTYlDs70TMyd WX6sernqwBeUuI6ep4If7+BxoNZxDPSAG/paKH54OjyqWcIa3cCz2M7vo w==; X-IronPort-AV: E=McAfee;i="6200,9189,10230"; a="243636356" X-IronPort-AV: E=Sophos;i="5.88,297,1635231600"; d="scan'208";a="243636356" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.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> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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