From nobody Thu Sep 18 21:54:33 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linux.intel.com ARC-Seal: i=1; a=rsa-sha256; t=1669962042; cv=none; d=zohomail.com; s=zohoarc; b=iptEhZ6Ti+SoOb/mcVZiiqMEoW6UpLLsc/4qOsH7HAIk601f0IgzgceiYC/A4v/olAE2VPAZhucdR1XpGKCr+hAilewkOGJMYsz7jWxpcm3S8rEM9zEBBi5xnCQ1PhHolVQ0VbUVTz6ptU4MYnxchukq/dII3e8l0QhLyh9/wqM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1669962042; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=5l4bbgIU+KNMUQwtsv66wFTG6GccOEOAAAgbwFDAWJ4=; b=A4wojSHogIfeO0xNbkCqmyni+lobLnjQF144RsZHjGqr5jbyvXprcXBOQl2yIjRvGyjHPCg7JTu4Rc3o49ty8wrev4mL0lEwvK3XYka1gWW8cf8kiSUu1jfLSbE8uFRvvqXnaAdfpvfr2rmDtyFlnvmwS8ZL9tp4zlcBgN40JIs= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1669962042448781.0838236918854; Thu, 1 Dec 2022 22:20:42 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p0zOi-0004la-Ip; Fri, 02 Dec 2022 01:19:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0zOd-0004ha-JG for qemu-devel@nongnu.org; Fri, 02 Dec 2022 01:19:39 -0500 Received: from mga07.intel.com ([134.134.136.100]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0zOb-000836-7U for qemu-devel@nongnu.org; Fri, 02 Dec 2022 01:19:39 -0500 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Dec 2022 22:19:34 -0800 Received: from chaop.bj.intel.com ([10.240.193.75]) by FMSMGA003.fm.intel.com with ESMTP; 01 Dec 2022 22:19:23 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669961977; x=1701497977; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=uHWX+bmiWvi8twUa4xphTJMpG6518qs7AwJd83WeEzU=; b=hLMOo7SBBCgHgYf2Z/7tSHoz695PCXQFwsMazU2iDBZhXhnlDgWOc3It ftTHaLTiqko8YAkT/s8lXPws9AqnpfDSkeVeiq4U6npGDbWOfYoUnYh1H 85rRleyF4xYciTWtW9j1ZA4MeEikgMKjpT01pdaNdVbvO+ajRQBHC24Hl XBbRmu1VX4zIv6+vUn82i47D2f/8NRDcL1wwA5SmTvkx/7cGsibzg+Z29 Sbfjixm4OYQBqveMgnJ/TZHcoD2lIMr6LsQueFjowCY5Br7g5pJagphWt AOTtw9GpwnlXb36kIWwMROupRYxGjrg9DECW+7f5GITm8A1K/7jIqx5V6 g==; X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="380170646" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="380170646" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10548"; a="733698745" X-IronPort-AV: E=Sophos;i="5.96,210,1665471600"; d="scan'208";a="733698745" 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 , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , 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, wei.w.wang@intel.com Subject: [PATCH v10 7/9] KVM: Update lpage info when private/shared memory are mixed Date: Fri, 2 Dec 2022 14:13:45 +0800 Message-Id: <20221202061347.1070246-8-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=134.134.136.100; envelope-from=chao.p.peng@linux.intel.com; helo=mga07.intel.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1669962043699100005 Content-Type: text/plain; charset="utf-8" A large page with mixed private/shared subpages can't be mapped as large page since its sub private/shared pages are from different memory backends and may also treated by architecture differently. When private/shared memory are mixed in a large page, the current lpage_info is not sufficient to decide whether the page can be mapped as large page or not and additional private/shared mixed information is needed. Tracking this 'mixed' information with the current 'count' like disallow_lpage is a bit challenge so reserve a bit in 'disallow_lpage' to indicate a large page has mixed private/share subpages and update this 'mixed' bit whenever the memory attribute is changed between private and shared. Signed-off-by: Chao Peng --- arch/x86/include/asm/kvm_host.h | 8 ++ arch/x86/kvm/mmu/mmu.c | 134 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 19 +++++ virt/kvm/kvm_main.c | 9 ++- 5 files changed, 169 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index 283cbb83d6ae..7772ab37ac89 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ #include =20 #define __KVM_HAVE_ARCH_VCPU_DEBUGFS +#define __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES =20 #define KVM_MAX_VCPUS 1024 =20 @@ -1011,6 +1012,13 @@ struct kvm_vcpu_arch { #endif }; =20 +/* + * Use a bit in disallow_lpage to indicate private/shared pages mixed at t= he + * 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 e2c70b5afa3e..2190fd8c95c0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -763,11 +763,16 @@ static void update_gfn_disallow_lpage_count(const str= uct kvm_memory_slot *slot, { struct kvm_lpage_info *linfo; int i; + int disallow_count; =20 for (i =3D PG_LEVEL_2M; i <=3D KVM_MAX_HUGEPAGE_LEVEL; ++i) { linfo =3D lpage_info_slot(gfn, slot, i); + + disallow_count =3D linfo->disallow_lpage & KVM_LPAGE_COUNT_MAX; + WARN_ON(disallow_count + count < 0 || + disallow_count > KVM_LPAGE_COUNT_MAX - count); + linfo->disallow_lpage +=3D count; - WARN_ON(linfo->disallow_lpage < 0); } } =20 @@ -6986,3 +6991,130 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) if (kvm->arch.nx_huge_page_recovery_thread) kthread_stop(kvm->arch.nx_huge_page_recovery_thread); } + +static bool linfo_is_mixed(struct kvm_lpage_info *linfo) +{ + return linfo->disallow_lpage & KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static void linfo_set_mixed(gfn_t gfn, struct kvm_memory_slot *slot, + int level, bool mixed) +{ + struct kvm_lpage_info *linfo =3D lpage_info_slot(gfn, slot, level); + + if (mixed) + linfo->disallow_lpage |=3D KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &=3D ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static bool is_expected_attr_entry(void *entry, unsigned long expected_att= rs) +{ + bool expect_private =3D expected_attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; + + if (xa_to_value(entry) & KVM_MEMORY_ATTRIBUTE_PRIVATE) { + if (!expect_private) + return false; + } else if (expect_private) + return false; + + return true; +} + +static bool mem_attrs_mixed_2m(struct kvm *kvm, unsigned long attrs, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn =3D start; + void *entry; + bool mixed =3D false; + + rcu_read_lock(); + entry =3D xas_load(&xas); + while (gfn < end) { + if (xas_retry(&xas, entry)) + continue; + + KVM_BUG_ON(gfn !=3D xas.xa_index, kvm); + + if (!is_expected_attr_entry(entry, attrs)) { + mixed =3D true; + break; + } + + entry =3D xas_next(&xas); + gfn++; + } + + rcu_read_unlock(); + return mixed; +} + +static bool mem_attrs_mixed(struct kvm *kvm, struct kvm_memory_slot *slot, + int level, unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long gfn; + + if (level =3D=3D PG_LEVEL_2M) + return mem_attrs_mixed_2m(kvm, attrs, start, end); + + for (gfn =3D start; gfn < end; gfn +=3D KVM_PAGES_PER_HPAGE(level - 1)) + if (linfo_is_mixed(lpage_info_slot(gfn, slot, level - 1)) || + !is_expected_attr_entry(xa_load(&kvm->mem_attr_array, gfn), + attrs)) + return true; + return false; +} + +static void kvm_update_lpage_private_shared_mixed(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + unsigned long pages, mask; + gfn_t gfn, gfn_end, first, last; + int level; + bool mixed; + + /* + * The sequence matters here: we set the higher level basing on the + * lower level's scanning result. + */ + for (level =3D PG_LEVEL_2M; level <=3D KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages =3D KVM_PAGES_PER_HPAGE(level); + mask =3D ~(pages - 1); + first =3D start & mask; + last =3D (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they will not be mixed. + */ + gfn =3D max(first, slot->base_gfn); + gfn_end =3D min(first + pages, slot->base_gfn + slot->npages); + mixed =3D mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + + if (first =3D=3D last) + return; + + for (gfn =3D first + pages; gfn < last; gfn +=3D pages) + linfo_set_mixed(gfn, slot, level, false); + + gfn =3D last; + gfn_end =3D min(last + pages, slot->base_gfn + slot->npages); + mixed =3D mem_attrs_mixed(kvm, slot, level, attrs, gfn, gfn_end); + linfo_set_mixed(gfn, slot, level, mixed); + } +} + +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ + if (kvm_slot_can_be_private(slot)) + kvm_update_lpage_private_shared_mixed(kvm, slot, attrs, + start, end); +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a07380f8d3c..5aefcff614d2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12362,6 +12362,8 @@ static int kvm_alloc_memslot_metadata(struct kvm *k= vm, if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1)) linfo[lpages - 1].disallow_lpage =3D 1; ugfn =3D slot->userspace_addr >> PAGE_SHIFT; + if (kvm_slot_can_be_private(slot)) + ugfn |=3D 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 3331c0c92838..25099c94e770 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -592,6 +592,11 @@ struct kvm_memory_slot { struct restrictedmem_notifier notifier; }; =20 +static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *s= lot) +{ + return slot && (slot->flags & KVM_MEM_PRIVATE); +} + static inline bool kvm_slot_dirty_track_enabled(const struct kvm_memory_sl= ot *slot) { return slot->flags & KVM_MEM_LOG_DIRTY_PAGES; @@ -2316,4 +2321,18 @@ static inline void kvm_account_pgtable_pages(void *v= irt, int nr) /* Max number of entries allowed for each kvm dirty ring */ #define KVM_DIRTY_RING_MAX_ENTRIES 65536 =20 +#ifdef __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES +void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end); +#else +static inline void kvm_arch_set_memory_attributes(struct kvm *kvm, + struct kvm_memory_slot *slot, + unsigned long attrs, + gfn_t start, gfn_t end) +{ +} +#endif /* __KVM_HAVE_ARCH_SET_MEMORY_ATTRIBUTES */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 4e1e1e113bf0..e107afea32f0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2354,7 +2354,8 @@ static u64 kvm_supported_mem_attributes(struct kvm *k= vm) return 0; } =20 -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 long attrs) { struct kvm_gfn_range gfn_range; struct kvm_memory_slot *slot; @@ -2378,6 +2379,10 @@ static void kvm_unmap_mem_range(struct kvm *kvm, gfn= _t start, gfn_t end) gfn_range.slot =3D slot; =20 r |=3D kvm_unmap_gfn_range(kvm, &gfn_range); + + kvm_arch_set_memory_attributes(kvm, slot, attrs, + gfn_range.start, + gfn_range.end); } } =20 @@ -2427,7 +2432,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm= *kvm, idx =3D srcu_read_lock(&kvm->srcu); KVM_MMU_LOCK(kvm); if (i > start) - kvm_unmap_mem_range(kvm, start, i); + kvm_unmap_mem_range(kvm, start, i, attrs->attributes); kvm_mmu_invalidate_end(kvm); KVM_MMU_UNLOCK(kvm); srcu_read_unlock(&kvm->srcu, idx); --=20 2.25.1