From patchwork Thu Dec 23 12:30:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12698246 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 CC2B8C43217 for ; Thu, 23 Dec 2021 12:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348422AbhLWMcS (ORCPT ); Thu, 23 Dec 2021 07:32:18 -0500 Received: from mga14.intel.com ([192.55.52.115]:56991 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348411AbhLWMcR (ORCPT ); Thu, 23 Dec 2021 07:32:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640262737; x=1671798737; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=4zBy2wqGUUHRa+bg8KFrUxUekBSmOOoI4eennjfoLXQ=; b=I9UsUNKoqYJWpUHAm/OqCdNPYfHIFbkwPHdL5+EXKIe5T4b4Cs8i4uqI izXCECctpB44wkkeCVg19fdvDcXt8l5kiYKhaSe9sB2j+4iaO9y8WyuTJ 1qnr1ewgr75X0bA6C7ySo+Ag8ii45QZSlrMV7LXWQwrDG/WzQZS/7U2j+ SUb/HnV07ZxngQmt63nWn+ijT+H9xZ73gWQQlZbyLrrbenzzBS9nUIVaz X225qFLhg4SVK/o2p4xC3MBONYSVSw+E8RKGEW5BkJmx4boiqIfgWTa/E 42g4OcLvQ2vHVKOaRpcerBz7GcU3GLfFBzdKtrGhbbc8JS8PnoNNxbMIZ w==; X-IronPort-AV: E=McAfee;i="6200,9189,10206"; a="241040454" X-IronPort-AV: E=Sophos;i="5.88,229,1635231600"; d="scan'208";a="241040454" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Dec 2021 04:32:16 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,229,1635231600"; d="scan'208";a="522078930" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 23 Dec 2021 04:32:09 -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, john.ji@intel.com, susie.li@intel.com, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com Subject: [PATCH v3 kvm/queue 10/16] KVM: Implement fd-based memory invalidation Date: Thu, 23 Dec 2021 20:30:05 +0800 Message-Id: <20211223123011.41044-11-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211223123011.41044-1-chao.p.peng@linux.intel.com> References: <20211223123011.41044-1-chao.p.peng@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM gets notified when userspace punches a hole in a fd which is used for guest memory. KVM should invalidate the mapping in the secondary MMU page tables. This is the same logic as MMU notifier invalidation except the fd related information is carried around to indicate the memory range. KVM hence can reuse most of existing MMU notifier invalidation code including looping through the memslots and then calling into kvm_unmap_gfn_range() which should do whatever needed for fd-based memory unmapping (e.g. for private memory managed by TDX it may need call into SEAM-MODULE). Signed-off-by: Yu Zhang Signed-off-by: Chao Peng --- include/linux/kvm_host.h | 8 ++++- virt/kvm/kvm_main.c | 69 +++++++++++++++++++++++++++++++--------- virt/kvm/memfd.c | 2 ++ 3 files changed, 63 insertions(+), 16 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 07863ff855cd..be567925831b 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -233,7 +233,7 @@ bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); #endif -#ifdef KVM_ARCH_WANT_MMU_NOTIFIER +#if defined(KVM_ARCH_WANT_MMU_NOTIFIER) || defined(CONFIG_MEMFD_OPS) struct kvm_gfn_range { struct kvm_memory_slot *slot; gfn_t start; @@ -2012,4 +2012,10 @@ 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_MEMFD_OPS +int kvm_memfd_invalidate_range(struct kvm *kvm, struct inode *inode, + unsigned long start, unsigned long end); +#endif /* CONFIG_MEMFD_OPS */ + + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7b7530b1ea1e..f495c1a313bd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -468,7 +468,8 @@ void kvm_destroy_vcpus(struct kvm *kvm) } EXPORT_SYMBOL_GPL(kvm_destroy_vcpus); -#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) +#if defined(CONFIG_MEMFD_OPS) ||\ + (defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)) typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range); @@ -595,6 +596,30 @@ static __always_inline int __kvm_handle_useraddr_range(struct kvm *kvm, /* The notifiers are averse to booleans. :-( */ return (int)ret; } + +static void mn_active_invalidate_count_inc(struct kvm *kvm) +{ + spin_lock(&kvm->mn_invalidate_lock); + kvm->mn_active_invalidate_count++; + spin_unlock(&kvm->mn_invalidate_lock); + +} + +static void mn_active_invalidate_count_dec(struct kvm *kvm) +{ + bool wake; + + spin_lock(&kvm->mn_invalidate_lock); + wake = (--kvm->mn_active_invalidate_count == 0); + spin_unlock(&kvm->mn_invalidate_lock); + + /* + * There can only be one waiter, since the wait happens under + * slots_lock. + */ + if (wake) + rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait); +} #endif #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER) @@ -732,9 +757,7 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, * * Pairs with the decrement in range_end(). */ - spin_lock(&kvm->mn_invalidate_lock); - kvm->mn_active_invalidate_count++; - spin_unlock(&kvm->mn_invalidate_lock); + mn_active_invalidate_count_inc(kvm); __kvm_handle_useraddr_range(kvm, &useraddr_range); @@ -773,21 +796,11 @@ static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, .may_block = mmu_notifier_range_blockable(range), .inode = NULL, }; - bool wake; __kvm_handle_useraddr_range(kvm, &useraddr_range); /* Pairs with the increment in range_start(). */ - spin_lock(&kvm->mn_invalidate_lock); - wake = (--kvm->mn_active_invalidate_count == 0); - spin_unlock(&kvm->mn_invalidate_lock); - - /* - * There can only be one waiter, since the wait happens under - * slots_lock. - */ - if (wake) - rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait); + mn_active_invalidate_count_dec(kvm); BUG_ON(kvm->mmu_notifier_count < 0); } @@ -872,6 +885,32 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ +#ifdef CONFIG_MEMFD_OPS +int kvm_memfd_invalidate_range(struct kvm *kvm, struct inode *inode, + unsigned long start, unsigned long end) +{ + int ret; + const struct kvm_useraddr_range useraddr_range = { + .start = start, + .end = end, + .pte = __pte(0), + .handler = kvm_unmap_gfn_range, + .on_lock = (void *)kvm_null_fn, + .flush_on_ret = true, + .may_block = false, + .inode = inode, + }; + + + /* Prevent memslot modification */ + mn_active_invalidate_count_inc(kvm); + ret = __kvm_handle_useraddr_range(kvm, &useraddr_range); + mn_active_invalidate_count_dec(kvm); + + return ret; +} +#endif /* CONFIG_MEMFD_OPS */ + #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER static int kvm_pm_notifier_call(struct notifier_block *bl, unsigned long state, diff --git a/virt/kvm/memfd.c b/virt/kvm/memfd.c index 662393a76782..547f65f5a187 100644 --- a/virt/kvm/memfd.c +++ b/virt/kvm/memfd.c @@ -16,6 +16,8 @@ static const struct memfd_pfn_ops *memfd_ops; static void memfd_invalidate_page_range(struct inode *inode, void *owner, pgoff_t start, pgoff_t end) { + kvm_memfd_invalidate_range(owner, inode, start >> PAGE_SHIFT, + end >> PAGE_SHIFT); } static void memfd_fallocate(struct inode *inode, void *owner,