From patchwork Tue Oct 25 15:13:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 10873 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:6687:0:0:0:0:0 with SMTP id l7csp1068144wru; Tue, 25 Oct 2022 08:26:43 -0700 (PDT) X-Google-Smtp-Source: AMsMyM6SEr2u0yRi8UgEQ5IkIFUoF6tbfe3uW+lP6rOdn3x0QOHEY+iOEqZl2+he0Sl6Fs0ov8Ec X-Received: by 2002:a17:907:3f94:b0:78d:9d2f:3002 with SMTP id hr20-20020a1709073f9400b0078d9d2f3002mr32739680ejc.40.1666711603584; Tue, 25 Oct 2022 08:26:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666711603; cv=none; d=google.com; s=arc-20160816; b=dhMZRRLkMiZm2i4xjNeJ8iLqQA6Y4yjSc2Btr8Izq57aCEg1qGPl2fNH+1qD9l21qu x1XWtrRvMeUTXxnB2WqaSfKqWyMLdmw+bVoZeRnA9S5gZW+e6jwu5phA9stec1XCLZSq /YISGr7PdTRNl1fN3zLHr6rGP6atsoX5X/1U47JwiHah/h4PJkxMvBvnGdBUCPE5IHNr 4y2K7W2fwg7I7yIwkAgB3XhqRbbRRgZ3LNb7/qOSDOyaa/K6rjh0TkaL7DRGS8zfWssj OPMoHduGYCrlHn6rjuAwRxYhq4IXsJpOEkNOCFNsHZ8R1DgJkmMCBkOvdjYLt3w+lB+d vINQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=dmMeA0i+XC1aI8CmAVcc6CO7d+pGCGu2hdfG6xQJpR0=; b=Z3g3mOa+iyRAvz9wf3kk1KgHXME7UPv3pWbx5nGjtGu/uu3PkS9JMC3vUqT43LXh48 7EwSjZ39rNskrRTGmjSqz9sTTm9YMzzwPIfFdHIOchByD/uoPFFA+IS35sK9F7is5l74 0nJ/AYkKBVGugDP7Qvff7pkuNgIvyvaQKNpHX+J4Ix6BuWqilzEXo7vrfYq3OqWCiXRl AgrT5ihJUCa0jMeSaeTUS7yga/C7sQX3+pcbJ9aHf3Gxnv7GFKJIjwfHu2+jd10Mj+le mVCyWtjy3whg6y2mmk/CGWiud5XLXMJdtZ5jsZtNLSSvK2JlToMED1xIk8KdpUTqDZfM PrXw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=mqvnKObf; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id qq17-20020a17090720d100b007879bc7eacfsi2732461ejb.93.2022.10.25.08.26.19; Tue, 25 Oct 2022 08:26:43 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=mqvnKObf; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233258AbiJYPVj (ORCPT + 99 others); Tue, 25 Oct 2022 11:21:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233256AbiJYPVG (ORCPT ); Tue, 25 Oct 2022 11:21:06 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7385A15A17; Tue, 25 Oct 2022 08:19:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666711194; x=1698247194; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0kS2wF3HRGDR5BE6p747FISp0sobPFWYTxerbWnA2RQ=; b=mqvnKObfbsE2dXlhe1LXnddPYScwtEC585SujEcj7FrEyNjf5pUD9fIc 0SumgN9umwochEJu4zdsmFL/ipc84nYaecYApwWfFrnTQWxQSd5UoBBE2 FmKXl+YOqKECGwoGj1ceSBbg4HtgiGL35zdyfUxYWAzoSF3fyCKFjhyFw ZRuy+RrpKLisE8M9eWvGnKeXxd8EYIltHDq+nGsMNm5MXMIZcRrJWUM6D SpWn9G/jsWLTwDK5bkPgSckvhTL3g1DH2xtcfBTb8baslprhY90sN0vy3 LrWS3pF9rOjcYKin0YqwcERKwSh8lfbm6OF2R5g3cwpg6jz9obp47HPGo w==; X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="308799868" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="308799868" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2022 08:19:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10510"; a="736865704" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="736865704" Received: from chaop.bj.intel.com ([10.240.193.75]) by fmsmga002.fm.intel.com with ESMTP; 25 Oct 2022 08:19:21 -0700 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@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 , Shuah Khan , 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 , tabba@google.com, Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: [PATCH v9 6/8] KVM: Update lpage info when private/shared memory are mixed Date: Tue, 25 Oct 2022 23:13:42 +0800 Message-Id: <20221025151344.3784230-7-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747673786142767815?= X-GMAIL-MSGID: =?utf-8?q?1747673786142767815?= When private/shared memory are mixed in a large page, the lpage_info may not be accurate and should be updated with this mixed info. A large page has mixed pages can't be really mapped as large page since its private/shared pages are from different physical memory. Update lpage_info when private/shared memory attribute is changed. If both private and shared pages are within a large page region, it can't be mapped as large page. It's a bit challenge to track the mixed info in a 'count' like variable, this patch instead reserves a bit in 'disallow_lpage' to indicate a large page has mixed private/share pages. Signed-off-by: Chao Peng --- arch/x86/include/asm/kvm_host.h | 8 +++ arch/x86/kvm/mmu/mmu.c | 112 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 19 ++++++ virt/kvm/kvm_main.c | 16 +++-- 5 files changed, 152 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7551b6f9c31c..db811a54e3fd 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -37,6 +37,7 @@ #include #define __KVM_HAVE_ARCH_VCPU_DEBUGFS +#define __KVM_HAVE_ARCH_UPDATE_MEM_ATTR #define KVM_MAX_VCPUS 1024 @@ -952,6 +953,13 @@ struct kvm_vcpu_arch { #endif }; +/* + * Use a bit in disallow_lpage to indicate private/shared pages mixed at the + * level. The remaining bits are used as a reference count. + */ +#define KVM_LPAGE_PRIVATE_SHARED_MIXED (1U << 31) +#define KVM_LPAGE_COUNT_MAX ((1U << 31) - 1) + struct kvm_lpage_info { int disallow_lpage; }; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 33b1aec44fb8..67a9823a8c35 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -762,11 +762,16 @@ static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot, { struct kvm_lpage_info *linfo; int i; + int disallow_count; for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) { linfo = lpage_info_slot(gfn, slot, i); + + disallow_count = linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; + WARN_ON(disallow_count + count < 0 || + disallow_count > KVM_LPAGE_COUNT_MAX - count); + linfo->disallow_lpage += count; - WARN_ON(linfo->disallow_lpage < 0); } } @@ -6910,3 +6915,108 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) if (kvm->arch.nx_lpage_recovery_thread) kthread_stop(kvm->arch.nx_lpage_recovery_thread); } + +static inline bool linfo_is_mixed(struct kvm_lpage_info *linfo) +{ + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static inline void linfo_update_mixed(struct kvm_lpage_info *linfo, bool mixed) +{ + if (mixed) + linfo->disallow_lpage |= KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &= ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static bool mem_attr_is_mixed_2m(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn = start; + void *entry; + bool shared = attr == KVM_MEM_ATTR_SHARED; + bool mixed = false; + + rcu_read_lock(); + entry = xas_load(&xas); + while (gfn < end) { + if (xas_retry(&xas, entry)) + continue; + + KVM_BUG_ON(gfn != xas.xa_index, kvm); + + if ((entry && !shared) || (!entry && shared)) { + mixed = true; + goto out; + } + + entry = xas_next(&xas); + gfn++; + } +out: + rcu_read_unlock(); + return mixed; +} + +static bool mem_attr_is_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, + int level, unsigned int attr, + gfn_t start, gfn_t end) +{ + unsigned long gfn; + void *entry; + + if (level == PG_LEVEL_2M) + return mem_attr_is_mixed_2m(kvm, attr, start, end); + + entry = xa_load(&kvm->mem_attr_array, start); + for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) { + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1))) + return true; + if (xa_load(&kvm->mem_attr_array, gfn) != entry) + return true; + } + return false; +} + +void kvm_arch_update_mem_attr(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int attr, gfn_t start, gfn_t end) +{ + + unsigned long lpage_start, lpage_end; + unsigned long gfn, pages, mask; + int level; + + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), + "Unsupported mem attribute.\n"); + + /* + * The sequence matters here: we update the higher level basing on the + * lower level's scanning result. + */ + for (level = PG_LEVEL_2M; level <= KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages = KVM_PAGES_PER_HPAGE(level); + mask = ~(pages - 1); + lpage_start = max(start & mask, slot->base_gfn); + lpage_end = (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they are not mixed. + */ + linfo_update_mixed(lpage_info_slot(lpage_start, slot, level), + mem_attr_is_mixed(kvm, slot, level, attr, + lpage_start, start)); + + if (lpage_start == lpage_end) + return; + + for (gfn = lpage_start + pages; gfn < lpage_end; gfn += pages) + linfo_update_mixed(lpage_info_slot(gfn, slot, level), + false); + + linfo_update_mixed(lpage_info_slot(lpage_end, slot, level), + mem_attr_is_mixed(kvm, slot, level, attr, + end, lpage_end + pages)); + } +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 02ad31f46dd7..4276ca73bd7b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12563,6 +12563,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *kvm, if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) linfo[lpages - 1].disallow_lpage = 1; ugfn = slot->userspace_addr >> PAGE_SHIFT; + if (kvm_slot_can_be_private(slot)) + ugfn |= slot->restricted_offset >> PAGE_SHIFT; /* * If the gfn and userspace address are not aligned wrt each * other, disable large page support for this slot. diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4ce98fa0153c..6ce36065532c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2284,4 +2284,23 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 +#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM + +#define KVM_MEM_ATTR_SHARED 0x0001 +#define KVM_MEM_ATTR_PRIVATE 0x0002 + +#ifdef __KVM_HAVE_ARCH_UPDATE_MEM_ATTR +void kvm_arch_update_mem_attr(struct kvm *kvm, struct kvm_memory_slot *slot, + unsigned int attr, gfn_t start, gfn_t end); +#else +static inline void kvm_arch_update_mem_attr(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned int attr, + gfn_t start, gfn_t end) +{ +} +#endif + +#endif /* CONFIG_KVM_GENERIC_PRIVATE_MEM */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index fc3835826ace..13a37b4d9e97 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -939,7 +939,8 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM -static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) +static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end, + unsigned int attr) { struct kvm_gfn_range gfn_range; struct kvm_memory_slot *slot; @@ -963,6 +964,7 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) gfn_range.slot = slot; r |= kvm_unmap_gfn_range(kvm, &gfn_range); + kvm_arch_update_mem_attr(kvm, slot, attr, start, end); } } @@ -970,7 +972,6 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn_t start, gfn_t end) kvm_flush_remote_tlbs(kvm); } -#define KVM_MEM_ATTR_SHARED 0x0001 static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, bool is_private) { @@ -979,6 +980,7 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, void *entry; int idx; int r = 0; + unsigned int attr; if (size == 0 || gpa + size < gpa) return -EINVAL; @@ -992,7 +994,13 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, * Guest memory defaults to private, kvm->mem_attr_array only stores * shared memory. */ - entry = is_private ? NULL : xa_mk_value(KVM_MEM_ATTR_SHARED); + if (is_private) { + attr = KVM_MEM_ATTR_PRIVATE; + entry = NULL; + } else { + attr = KVM_MEM_ATTR_SHARED; + entry = xa_mk_value(KVM_MEM_ATTR_SHARED); + } idx = srcu_read_lock(&kvm->srcu); KVM_MMU_LOCK(kvm); @@ -1005,7 +1013,7 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, goto err; } - kvm_unmap_mem_range(kvm, start, end); + kvm_unmap_mem_range(kvm, start, end, attr); goto ret; err: