From patchwork Mon Jun 1 11:59:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11581929 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 89D00139A for ; Mon, 1 Jun 2020 12:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A18A207D5 for ; Mon, 1 Jun 2020 12:01:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NxDtM80g" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728197AbgFAMBf (ORCPT ); Mon, 1 Jun 2020 08:01:35 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:51511 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726287AbgFAMAO (ORCPT ); Mon, 1 Jun 2020 08:00:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591012811; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eLbQxtcB/NbUu4964QhGhTnT+waGk9vABahkdmb5jsk=; b=NxDtM80gd5nhMuQVDA/ig67V05LzFWKrcKLGPCbZuaypJNmUDfxr+FgVpDsdPS30BQwPWI PCegBJPteEUSet+9TJGDyJMVq9pZxs+LYn3rt3EsgQNkdTSSg64lk/c752ZS/N9NPae0pj VKhHI9eX1Wt/WfjnHDyFk1NnhaZVU5I= Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-301-3eNOazRlNKqzqxmRAQ-dHg-1; Mon, 01 Jun 2020 08:00:08 -0400 X-MC-Unique: 3eNOazRlNKqzqxmRAQ-dHg-1 Received: by mail-qt1-f199.google.com with SMTP id p9so5665230qtn.5 for ; Mon, 01 Jun 2020 05:00:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=eLbQxtcB/NbUu4964QhGhTnT+waGk9vABahkdmb5jsk=; b=lNljXu+bfI6UBowpHxZ0jKaL2dfLMsY93fA88Yln5i+kBh5XgEJhuwWDi9ktdXn7ZS neOhK/nlTKK6A9mV/JizyrAXWah5D5MS2lDJq6LxVSsgiLwry9CYoZcSvyLtkyVN+cMC PPs1Qoqs7UaeBBsAc675BaP4wPFnf4mCvthHO/1dq57n6PqXtIsdfq6ySKevCdm17RcD pbwMeTDDFSnd+D6LzFOAqyMB1ehsjtTYKUqrzz7PqUik+P5CoGQVJvygIh39ndv3K2mf ngyaGsSBvRAXznHVqfR4aE5fcSnZV8J1V8en4S6wdeLadpjgoXjHlc6pKlwXFMEeCk5X SfjQ== X-Gm-Message-State: AOAM531k8OC8ZoCy3jLPbBZkKYG6lX5FPklnxYCicajNi67h2fUG4iqz BM8FBD/od2gYEm9PzePvgGrztUjZ9M3e3hjdNnT0GxLvo51PgLOxiw8P387pQbyRmGUdhij5ITg RsF91NOjSEqMk X-Received: by 2002:a37:6513:: with SMTP id z19mr20469425qkb.234.1591012807502; Mon, 01 Jun 2020 05:00:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwaO619sqTdqlm+A3QK+2VRAsnHDRUlKcbHqhEJPM7kANLn1lqkULNYtLYnb+tXcj0nSAlW5A== X-Received: by 2002:a37:6513:: with SMTP id z19mr20469388qkb.234.1591012807133; Mon, 01 Jun 2020 05:00:07 -0700 (PDT) Received: from xz-x1.redhat.com ([2607:9880:19c0:32::2]) by smtp.gmail.com with ESMTPSA id l9sm14474185qki.90.2020.06.01.05.00.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Jun 2020 05:00:06 -0700 (PDT) From: Peter Xu To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Dr . David Alan Gilbert" , Andrew Jones , Vitaly Kuznetsov , Paolo Bonzini , "Michael S . Tsirkin" , Jason Wang , peterx@redhat.com, Sean Christopherson , Kevin Tian Subject: [PATCH v10 03/14] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR] Date: Mon, 1 Jun 2020 07:59:46 -0400 Message-Id: <20200601115957.1581250-4-peterx@redhat.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200601115957.1581250-1-peterx@redhat.com> References: <20200601115957.1581250-1-peterx@redhat.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Originally, we have three code paths that can dirty a page without vcpu context for X86: - init_rmode_identity_map - init_rmode_tss - kvmgt_rw_gpa init_rmode_identity_map and init_rmode_tss will be setup on destination VM no matter what (and the guest cannot even see them), so it does not make sense to track them at all. To do this, allow __x86_set_memory_region() to return the userspace address that just allocated to the caller. Then in both of the functions we directly write to the userspace address instead of calling kvm_write_*() APIs. Another trivial change is that we don't need to explicitly clear the identity page table root in init_rmode_identity_map() because no matter what we'll write to the whole page with 4M huge page entries. Suggested-by: Paolo Bonzini Signed-off-by: Peter Xu --- arch/x86/include/asm/kvm_host.h | 3 +- arch/x86/kvm/svm/avic.c | 11 +++-- arch/x86/kvm/vmx/vmx.c | 84 ++++++++++++++++----------------- arch/x86/kvm/x86.c | 44 +++++++++++++---- 4 files changed, 86 insertions(+), 56 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 42a2d0d3984a..39477f8f3f2c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1650,7 +1650,8 @@ void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); int kvm_is_in_guest(void); -int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size); +void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, + u32 size); bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu); bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index e80daa98682f..86e9621ba026 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -235,7 +235,9 @@ static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu, */ static int avic_update_access_page(struct kvm *kvm, bool activate) { - int ret = 0; + void __user *ret; + int r = 0; + mutex_lock(&kvm->slots_lock); /* @@ -251,13 +253,16 @@ static int avic_update_access_page(struct kvm *kvm, bool activate) APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, APIC_DEFAULT_PHYS_BASE, activate ? PAGE_SIZE : 0); - if (ret) + if (IS_ERR(ret)) { + r = PTR_ERR(ret); goto out; + } + kvm->arch.apic_access_page_done = activate; out: mutex_unlock(&kvm->slots_lock); - return ret; + return r; } static int avic_init_backing_page(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index c2c6335a998c..c44637e8e9d6 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3442,34 +3442,26 @@ static bool guest_state_valid(struct kvm_vcpu *vcpu) return true; } -static int init_rmode_tss(struct kvm *kvm) +static int init_rmode_tss(struct kvm *kvm, void __user *ua) { - gfn_t fn; - u16 data = 0; - int idx, r; + const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0))); + u16 data; + int i, r; + + for (i = 0; i < 3; i++) { + r = __copy_to_user(ua + PAGE_SIZE * i, zero_page, PAGE_SIZE); + if (r) + return -EFAULT; + } - idx = srcu_read_lock(&kvm->srcu); - fn = to_kvm_vmx(kvm)->tss_addr >> PAGE_SHIFT; - r = kvm_clear_guest_page(kvm, fn, 0, PAGE_SIZE); - if (r < 0) - goto out; data = TSS_BASE_SIZE + TSS_REDIRECTION_SIZE; - r = kvm_write_guest_page(kvm, fn++, &data, - TSS_IOPB_BASE_OFFSET, sizeof(u16)); - if (r < 0) - goto out; - r = kvm_clear_guest_page(kvm, fn++, 0, PAGE_SIZE); - if (r < 0) - goto out; - r = kvm_clear_guest_page(kvm, fn, 0, PAGE_SIZE); - if (r < 0) - goto out; + r = __copy_to_user(ua + TSS_IOPB_BASE_OFFSET, &data, sizeof(u16)); + if (r) + return -EFAULT; + data = ~0; - r = kvm_write_guest_page(kvm, fn, &data, - RMODE_TSS_SIZE - 2 * PAGE_SIZE - 1, - sizeof(u8)); -out: - srcu_read_unlock(&kvm->srcu, idx); + r = __copy_to_user(ua + RMODE_TSS_SIZE - 1, &data, sizeof(u8)); + return r; } @@ -3477,7 +3469,7 @@ static int init_rmode_identity_map(struct kvm *kvm) { struct kvm_vmx *kvm_vmx = to_kvm_vmx(kvm); int i, r = 0; - kvm_pfn_t identity_map_pfn; + void __user *uaddr; u32 tmp; /* Protect kvm_vmx->ept_identity_pagetable_done. */ @@ -3488,24 +3480,25 @@ static int init_rmode_identity_map(struct kvm *kvm) if (!kvm_vmx->ept_identity_map_addr) kvm_vmx->ept_identity_map_addr = VMX_EPT_IDENTITY_PAGETABLE_ADDR; - identity_map_pfn = kvm_vmx->ept_identity_map_addr >> PAGE_SHIFT; - r = __x86_set_memory_region(kvm, IDENTITY_PAGETABLE_PRIVATE_MEMSLOT, - kvm_vmx->ept_identity_map_addr, PAGE_SIZE); - if (r < 0) + uaddr = __x86_set_memory_region(kvm, + IDENTITY_PAGETABLE_PRIVATE_MEMSLOT, + kvm_vmx->ept_identity_map_addr, + PAGE_SIZE); + if (IS_ERR(uaddr)) { + r = PTR_ERR(uaddr); goto out; + } - r = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE); - if (r < 0) - goto out; /* Set up identity-mapping pagetable for EPT in real mode */ for (i = 0; i < PT32_ENT_PER_PAGE; i++) { tmp = (i << 22) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE); - r = kvm_write_guest_page(kvm, identity_map_pfn, - &tmp, i * sizeof(tmp), sizeof(tmp)); - if (r < 0) + r = __copy_to_user(uaddr + i * sizeof(tmp), &tmp, sizeof(tmp)); + if (r) { + r = -EFAULT; goto out; + } } kvm_vmx->ept_identity_pagetable_done = true; @@ -3532,19 +3525,22 @@ static void seg_setup(int seg) static int alloc_apic_access_page(struct kvm *kvm) { struct page *page; - int r = 0; + void __user *r; + int ret = 0; mutex_lock(&kvm->slots_lock); if (kvm->arch.apic_access_page_done) goto out; r = __x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, APIC_DEFAULT_PHYS_BASE, PAGE_SIZE); - if (r) + if (IS_ERR(r)) { + ret = PTR_ERR(r); goto out; + } page = gfn_to_page(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT); if (is_error_page(page)) { - r = -EFAULT; + ret = -EFAULT; goto out; } @@ -3556,7 +3552,7 @@ static int alloc_apic_access_page(struct kvm *kvm) kvm->arch.apic_access_page_done = true; out: mutex_unlock(&kvm->slots_lock); - return r; + return ret; } int allocate_vpid(void) @@ -4483,7 +4479,7 @@ static int vmx_interrupt_allowed(struct kvm_vcpu *vcpu) static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr) { - int ret; + void __user *ret; if (enable_unrestricted_guest) return 0; @@ -4493,10 +4489,12 @@ static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr) PAGE_SIZE * 3); mutex_unlock(&kvm->slots_lock); - if (ret) - return ret; + if (IS_ERR(ret)) + return PTR_ERR(ret); + to_kvm_vmx(kvm)->tss_addr = addr; - return init_rmode_tss(kvm); + + return init_rmode_tss(kvm, ret); } static int vmx_set_identity_map_addr(struct kvm *kvm, u64 ident_addr) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ac7b0e6f4000..5c106ca948ed 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9826,7 +9826,32 @@ void kvm_arch_sync_events(struct kvm *kvm) kvm_free_pit(kvm); } -int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) +#define ERR_PTR_USR(e) ((void __user *)ERR_PTR(e)) + +/** + * __x86_set_memory_region: Setup KVM internal memory slot + * + * @kvm: the kvm pointer to the VM. + * @id: the slot ID to setup. + * @gpa: the GPA to install the slot (unused when @size == 0). + * @size: the size of the slot. Set to zero to uninstall a slot. + * + * This function helps to setup a KVM internal memory slot. Specify + * @size > 0 to install a new slot, while @size == 0 to uninstall a + * slot. The return code can be one of the following: + * + * HVA: on success (uninstall will return a bogus HVA) + * -errno: on error + * + * The caller should always use IS_ERR() to check the return value + * before use. Note, the KVM internal memory slots are guaranteed to + * remain valid and unchanged until the VM is destroyed, i.e., the + * GPA->HVA translation will not change. However, the HVA is a user + * address, i.e. its accessibility is not guaranteed, and must be + * accessed via __copy_{to,from}_user(). + */ +void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, + u32 size) { int i, r; unsigned long hva, uninitialized_var(old_npages); @@ -9835,12 +9860,12 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) /* Called with kvm->slots_lock held. */ if (WARN_ON(id >= KVM_MEM_SLOTS_NUM)) - return -EINVAL; + return ERR_PTR_USR(-EINVAL); slot = id_to_memslot(slots, id); if (size) { if (slot && slot->npages) - return -EEXIST; + return ERR_PTR_USR(-EEXIST); /* * MAP_SHARED to prevent internal slot pages from being moved @@ -9849,17 +9874,18 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) hva = vm_mmap(NULL, 0, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, 0); if (IS_ERR((void *)hva)) - return PTR_ERR((void *)hva); + return (void __user *)hva; } else { - if (!slot || !slot->npages) - return 0; - /* * Stuff a non-canonical value to catch use-after-delete. This * ends up being 0 on 32-bit KVM, but there's no better * alternative. */ hva = (unsigned long)(0xdeadull << 48); + + if (!slot || !slot->npages) + return (void __user *)hva; + old_npages = slot->npages; } @@ -9873,13 +9899,13 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) m.memory_size = size; r = __kvm_set_memory_region(kvm, &m); if (r < 0) - return r; + return ERR_PTR_USR(r); } if (!size) vm_munmap(hva, old_npages * PAGE_SIZE); - return 0; + return (void __user *)hva; } EXPORT_SYMBOL_GPL(__x86_set_memory_region);