From nobody Mon Feb 9 08:11:46 2026 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=1663253005; cv=none; d=zohomail.com; s=zohoarc; b=BKOrpOhNjHp7Jx+RpUmJQOoDaowxY4N7TcBkoFw/FfBOy5EWDA0xNfqIJ3lHh6HUkHqD03dcT1vbUKqJ4ea8R9PSj2qlD2Tbj8GcMIZ/+Uu3emrJdJBSoXSNZFkMX0t4dTAuB824JE0jIHJroTG26TOFUYnmhCO4rpumJdgMBnk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1663253005; 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=ZOEVjuUzfphXbRyZHy0EZbIAaeZYUd9HmD2zyBBdSLA=; b=IyNrGu4XkLhcHK9L80p3Xp0iq/MbRYPnF2NOCs+LCuMCXTiN3VVoXxGZDf8o4xJkWGuDF9z9GJcpcrRFKGk3PANDgxfsegya/tos48ga8+UEQam7pOZ6Bvhtn0kUPtkk5Dd6/spIfaDGUBzTLN07QwTeEyOAjkHBeZeH+ytb2E8= 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 1663253005926299.5657256836821; Thu, 15 Sep 2022 07:43:25 -0700 (PDT) Received: from localhost ([::1]:54980 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oYq5M-0004qt-PN for importer@patchew.org; Thu, 15 Sep 2022 10:43:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55640) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oYpxN-00058O-Le for qemu-devel@nongnu.org; Thu, 15 Sep 2022 10:35:10 -0400 Received: from mga12.intel.com ([192.55.52.136]:60429) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oYpxH-0000sz-Q5 for qemu-devel@nongnu.org; Thu, 15 Sep 2022 10:35:06 -0400 Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 07:35:01 -0700 Received: from chaop.bj.intel.com ([10.240.193.75]) by fmsmga005.fm.intel.com with ESMTP; 15 Sep 2022 07:34:52 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663252503; x=1694788503; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=OdNh9Zw3Oa88e2pjFDCMImTzlT1i+7tGALsj6VLXH/Q=; b=W+jksVdapGFPukCG5SOBtNTJCx7AB1PmBKQ6qlndjPas0rfY0vO1A2Av CK2i9pwJYvVbn0UTPz4vBu2mdUWQDQ84fVKRkF8rqTOcSO0WhfjrdVErk /+5FkU0Wkn0Ub+MnWsg8GZyYUvygeoRMsES7x/6qBwgYJR/DWORPf4mXL O2X7tabtpuRM1rcJbCaFqTWgZClYi0/9fpKFwX0/AN6tw/r5Ngsa9jqw8 sZXTpgCDFi59zkRzqnoNi3PVBMlt94CNh099J8qwA6XnYjzDo9AE7BZN2 jwUyMfkbNbDw64oy6+EC0laq5pKN0X4vMxt31wmbRpqKJl1gv/2t0fmFS A==; X-IronPort-AV: E=McAfee;i="6500,9779,10470"; a="278458587" X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="278458587" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="945977198" From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@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 , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: [PATCH v8 6/8] KVM: Update lpage info when private/shared memory are mixed Date: Thu, 15 Sep 2022 22:29:11 +0800 Message-Id: <20220915142913.2213336-7-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> References: <20220915142913.2213336-1-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=192.55.52.136; envelope-from=chao.p.peng@linux.intel.com; helo=mga12.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_PASS=-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" X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1663253007808100001 Content-Type: text/plain; charset="utf-8" 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. This patch updates 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 include mixed private/share pages. Signed-off-by: Chao Peng --- arch/x86/include/asm/kvm_host.h | 8 +++ arch/x86/kvm/mmu/mmu.c | 119 +++++++++++++++++++++++++++++++- arch/x86/kvm/x86.c | 2 + include/linux/kvm_host.h | 17 +++++ virt/kvm/kvm_main.c | 11 ++- 5 files changed, 154 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_hos= t.h index cfad6ba1a70a..85119ed9527a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ =20 #define __KVM_HAVE_ARCH_VCPU_DEBUGFS #define __KVM_HAVE_ZAP_GFN_RANGE +#define __KVM_HAVE_ARCH_UPDATE_MEM_ATTR =20 #define KVM_MAX_VCPUS 1024 =20 @@ -945,6 +946,13 @@ 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 will be used as a reference count for other u= sers. + */ +#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 08abad4f3e6f..a0f198cede3d 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 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 @@ -6894,3 +6899,115 @@ 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 bool mem_attr_is_mixed(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ + XA_STATE(xas, &kvm->mem_attr_array, start); + gfn_t gfn =3D start; + void *entry; + bool shared, private; + bool mixed =3D false; + + if (attr =3D=3D KVM_MEM_ATTR_SHARED) { + shared =3D true; + private =3D false; + } else { + shared =3D false; + private =3D true; + } + + 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 (entry) + private =3D true; + else + shared =3D true; + + if (private && shared) { + mixed =3D true; + goto out; + } + + entry =3D xas_next(&xas); + gfn++; + } +out: + rcu_read_unlock(); + return mixed; +} + +static inline void update_mixed(struct kvm_lpage_info *linfo, bool mixed) +{ + if (mixed) + linfo->disallow_lpage |=3D KVM_LPAGE_PRIVATE_SHARED_MIXED; + else + linfo->disallow_lpage &=3D ~KVM_LPAGE_PRIVATE_SHARED_MIXED; +} + +static void update_mem_lpage_info(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; + + for (level =3D PG_LEVEL_2M; level <=3D KVM_MAX_HUGEPAGE_LEVEL; level++) { + pages =3D KVM_PAGES_PER_HPAGE(level); + mask =3D ~(pages - 1); + lpage_start =3D start & mask; + lpage_end =3D (end - 1) & mask; + + /* + * We only need to scan the head and tail page, for middle pages + * we know they are not mixed. + */ + update_mixed(lpage_info_slot(lpage_start, slot, level), + mem_attr_is_mixed(kvm, attr, lpage_start, + lpage_start + pages)); + + if (lpage_start =3D=3D lpage_end) + return; + + for (gfn =3D lpage_start + pages; gfn < lpage_end; gfn +=3D pages) + update_mixed(lpage_info_slot(gfn, slot, level), false); + + update_mixed(lpage_info_slot(lpage_end, slot, level), + mem_attr_is_mixed(kvm, attr, lpage_end, + lpage_end + pages)); + } +} + +void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int attr, + gfn_t start, gfn_t end) +{ + struct kvm_memory_slot *slot; + struct kvm_memslots *slots; + struct kvm_memslot_iter iter; + int i; + + WARN_ONCE(!(attr & (KVM_MEM_ATTR_PRIVATE | KVM_MEM_ATTR_SHARED)), + "Unsupported mem attribute.\n"); + + for (i =3D 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + slots =3D __kvm_memslots(kvm, i); + + kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) { + slot =3D iter.slot; + start =3D max(start, slot->base_gfn); + end =3D min(end, slot->base_gfn + slot->npages); + if (WARN_ON_ONCE(start >=3D end)) + continue; + + update_mem_lpage_info(kvm, slot, attr, start, end); + } + } +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 081f62ccc9a1..ef11cda6f13f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12321,6 +12321,8 @@ 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->private_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 d65690cae80b..fd36ce6597ad 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2277,4 +2277,21 @@ 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 =20 +#ifdef CONFIG_HAVE_KVM_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, unsigned int attr, + gfn_t start, gfn_t end); +#else +static inline void kvm_arch_update_mem_attr(struct kvm *kvm, unsigned int = attr, + gfn_t start, gfn_t end) +{ +} +#endif + +#endif /* CONFIG_HAVE_KVM_PRIVATE_MEM */ + #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index de5cce8c82c7..97d893f7482c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -938,13 +938,13 @@ static int kvm_init_mmu_notifier(struct kvm *kvm) #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */ =20 #ifdef CONFIG_HAVE_KVM_PRIVATE_MEM -#define KVM_MEM_ATTR_SHARED 0x0001 static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t siz= e, bool is_private) { gfn_t start, end; unsigned long index; void *entry; + int attr; int r; =20 if (size =3D=3D 0 || gpa + size < gpa) @@ -959,7 +959,13 @@ 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 =3D is_private ? NULL : xa_mk_value(KVM_MEM_ATTR_SHARED); + if (is_private) { + attr =3D KVM_MEM_ATTR_PRIVATE; + entry =3D NULL; + } else { + attr =3D KVM_MEM_ATTR_SHARED; + entry =3D xa_mk_value(KVM_MEM_ATTR_SHARED); + } =20 for (index =3D start; index < end; index++) { r =3D xa_err(xa_store(&kvm->mem_attr_array, index, entry, @@ -969,6 +975,7 @@ static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, g= pa_t gpa, gpa_t size, } =20 kvm_zap_gfn_range(kvm, start, end); + kvm_arch_update_mem_attr(kvm, attr, start, end); =20 return r; err: --=20 2.25.1