From patchwork Mon Apr 26 11:13:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 12224169 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E29ADC433ED for ; Mon, 26 Apr 2021 11:14:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4F1061131 for ; Mon, 26 Apr 2021 11:14:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233344AbhDZLPP (ORCPT ); Mon, 26 Apr 2021 07:15:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:55626 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233136AbhDZLPE (ORCPT ); Mon, 26 Apr 2021 07:15:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619435662; 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=ZYg8Crkswh89VN+DFuzaHYcgCCK2qIHNkdGv8Ve+zOk=; b=dpDDRxnfBRp6BNRf/F4VRqGJKGk5jGwES5OVjrFKLckRcM2ycyOXmhC2UkL8VcTrFbxJ0a EoxKzBxoqVqjLxgS1PHXGzZYmnxRlGOf0qFVOndXR09aJ5uxiC0XGO0y7PlM6xqTNf2dmJ wDdUiHblA2zQcKNB1A5C5hHDPE5NRqo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-216-S3ndQEJbP8OvJyZJ38N2zg-1; Mon, 26 Apr 2021 07:14:18 -0400 X-MC-Unique: S3ndQEJbP8OvJyZJ38N2zg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 62A9783DBF4; Mon, 26 Apr 2021 11:14:01 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.192.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id B41A45D9D0; Mon, 26 Apr 2021 11:13:56 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org (open list:DOCUMENTATION), Thomas Gleixner , Jonathan Corbet , Paolo Bonzini , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , Ingo Molnar , Borislav Petkov , Wanpeng Li , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , Joerg Roedel , Maxim Levitsky Subject: [PATCH v2 4/6] KVM: x86: Introduce KVM_GET_SREGS2 / KVM_SET_SREGS2 Date: Mon, 26 Apr 2021 14:13:31 +0300 Message-Id: <20210426111333.967729-5-mlevitsk@redhat.com> In-Reply-To: <20210426111333.967729-1-mlevitsk@redhat.com> References: <20210426111333.967729-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This is a new version of KVM_GET_SREGS / KVM_SET_SREGS. It has the following changes: * Has flags for future extensions * Has vcpu's PDPTS, which allows to save/restore them on migration. * Lacks obsolete interrupt bitmap (done now via KVM_SET_VCPU_EVENTS) New capability, KVM_CAP_SREGS2 is added to signal the userspace of this ioctl. Signed-off-by: Maxim Levitsky --- Documentation/virt/kvm/api.rst | 48 +++++++++++ arch/x86/include/asm/kvm_host.h | 7 ++ arch/x86/include/uapi/asm/kvm.h | 13 +++ arch/x86/kvm/kvm_cache_regs.h | 5 ++ arch/x86/kvm/x86.c | 139 ++++++++++++++++++++++++++------ include/uapi/linux/kvm.h | 4 + 6 files changed, 192 insertions(+), 24 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 8d614a577e43..6781e0a4bfa5 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5021,6 +5021,54 @@ see KVM_XEN_VCPU_SET_ATTR above. The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used with the KVM_XEN_VCPU_GET_ATTR ioctl. + +4.131 KVM_GET_SREGS2 +------------------ + +:Capability: KVM_CAP_SREGS2 +:Architectures: x86 +:Type: vcpu ioctl +:Parameters: struct kvm_sregs2 (out) +:Returns: 0 on success, -1 on error + +Reads special registers from the vcpu. +This ioctl (when supported) replaces the KVM_GET_SREGS. + +:: + +struct kvm_sregs2 { + /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ + struct kvm_segment cs, ds, es, fs, gs, ss; + struct kvm_segment tr, ldt; + struct kvm_dtable gdt, idt; + __u64 cr0, cr2, cr3, cr4, cr8; + __u64 efer; + __u64 apic_base; + __u64 flags; + __u64 pdptrs[4]; +}; + +flags values for ``kvm_sregs2``: + +``KVM_SREGS2_FLAGS_PDPTRS_VALID`` + + Indicates thats the struct contain valid PDPTR values. + + +4.132 KVM_SET_SREGS2 +------------------ + +:Capability: KVM_CAP_SREGS2 +:Architectures: x86 +:Type: vcpu ioctl +:Parameters: struct kvm_sregs2 (in) +:Returns: 0 on success, -1 on error + +Writes special registers into the vcpu. +See KVM_GET_SREGS2 for the data structures. +This ioctl (when supported) replaces the KVM_SET_SREGS. + + 5. The kvm_run structure ======================== diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 3e5fc80a35c8..943e19831e32 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -849,6 +849,13 @@ struct kvm_vcpu_arch { /* Protected Guests */ bool guest_state_protected; + + /* + * Do we need to reload the PDPTRs when entering the nested state? + * Set if the userspace used the KVM_SET_SREGS to set CR3 + * and thus didn't load the PDPTRs from the migration state. + */ + bool pdptr_reload_on_nesting_needed; }; struct kvm_lpage_info { diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 5a3022c8af82..46aef200b168 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -159,6 +159,19 @@ struct kvm_sregs { __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64]; }; +struct kvm_sregs2 { + /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ + struct kvm_segment cs, ds, es, fs, gs, ss; + struct kvm_segment tr, ldt; + struct kvm_dtable gdt, idt; + __u64 cr0, cr2, cr3, cr4, cr8; + __u64 efer; + __u64 apic_base; + __u64 flags; + __u64 pdptrs[4]; +}; +#define KVM_SREGS2_FLAGS_PDPTRS_VALID 1 + /* for KVM_GET_FPU and KVM_SET_FPU */ struct kvm_fpu { __u8 fpr[8][16]; diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index b8559b83c4ca..842a09711b80 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -125,6 +125,11 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index) return vcpu->arch.walk_mmu->pdptrs[index]; } +static inline void kvm_pdptr_write(struct kvm_vcpu *vcpu, int index, u64 value) +{ + vcpu->arch.walk_mmu->pdptrs[index] = value; +} + static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask) { ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3bf52ba5f2bb..967022b983a8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -113,6 +113,9 @@ static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags); static void store_regs(struct kvm_vcpu *vcpu); static int sync_regs(struct kvm_vcpu *vcpu); +static int __set_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2); +static void __get_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2); + struct kvm_x86_ops kvm_x86_ops __read_mostly; EXPORT_SYMBOL_GPL(kvm_x86_ops); @@ -3841,6 +3844,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) #endif case KVM_CAP_VM_COPY_ENC_CONTEXT_FROM: case KVM_CAP_EXIT_HYPERCALL: + case KVM_CAP_SREGS2: r = 1; break; case KVM_CAP_SET_GUEST_DEBUG2: @@ -4759,6 +4763,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp, void __user *argp = (void __user *)arg; int r; union { + struct kvm_sregs2 *sregs2; struct kvm_lapic_state *lapic; struct kvm_xsave *xsave; struct kvm_xcrs *xcrs; @@ -5131,6 +5136,28 @@ long kvm_arch_vcpu_ioctl(struct file *filp, break; } #endif + case KVM_GET_SREGS2: { + u.sregs2 = kzalloc(sizeof(struct kvm_sregs2), GFP_KERNEL); + r = -ENOMEM; + if (!u.sregs2) + goto out; + __get_sregs2(vcpu, u.sregs2); + r = -EFAULT; + if (copy_to_user(argp, u.sregs2, sizeof(struct kvm_sregs2))) + goto out; + r = 0; + break; + } + case KVM_SET_SREGS2: { + u.sregs2 = memdup_user(argp, sizeof(struct kvm_sregs2)); + if (IS_ERR(u.sregs2)) { + r = PTR_ERR(u.sregs2); + u.sregs2 = NULL; + goto out; + } + r = __set_sregs2(vcpu, u.sregs2); + break; + } default: r = -EINVAL; } @@ -9795,7 +9822,7 @@ void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l) } EXPORT_SYMBOL_GPL(kvm_get_cs_db_l_bits); -static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) +static void __get_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) { struct desc_ptr dt; @@ -9828,14 +9855,32 @@ static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) sregs->cr8 = kvm_get_cr8(vcpu); sregs->efer = vcpu->arch.efer; sregs->apic_base = kvm_get_apic_base(vcpu); +} - memset(sregs->interrupt_bitmap, 0, sizeof(sregs->interrupt_bitmap)); +static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) +{ + __get_sregs_common(vcpu, sregs); + + if (vcpu->arch.guest_state_protected) + return; if (vcpu->arch.interrupt.injected && !vcpu->arch.interrupt.soft) set_bit(vcpu->arch.interrupt.nr, (unsigned long *)sregs->interrupt_bitmap); } +static void __get_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2) +{ + int i; + + __get_sregs_common(vcpu, (struct kvm_sregs *)sregs2); + if (is_pae_paging(vcpu)) { + for (i = 0 ; i < 4 ; i++) + sregs2->pdptrs[i] = kvm_pdptr_read(vcpu, i); + sregs2->flags |= KVM_SREGS2_FLAGS_PDPTRS_VALID; + } +} + int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) { @@ -9947,11 +9992,9 @@ static bool kvm_is_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) return kvm_is_valid_cr4(vcpu, sregs->cr4); } -static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) +static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs, int *mmu_reset_needed) { struct msr_data apic_base_msr; - int mmu_reset_needed = 0; - int pending_vec, max_bits, idx; struct desc_ptr dt; int ret = -EINVAL; @@ -9963,8 +10006,9 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) if (kvm_set_apic_base(vcpu, &apic_base_msr)) goto out; + ret = 0; if (vcpu->arch.guest_state_protected) - goto skip_protected_regs; + goto out; dt.size = sregs->idt.limit; dt.address = sregs->idt.base; @@ -9974,32 +10018,22 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) static_call(kvm_x86_set_gdt)(vcpu, &dt); vcpu->arch.cr2 = sregs->cr2; - mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3; + *mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3; vcpu->arch.cr3 = sregs->cr3; kvm_register_mark_available(vcpu, VCPU_EXREG_CR3); kvm_set_cr8(vcpu, sregs->cr8); - mmu_reset_needed |= vcpu->arch.efer != sregs->efer; + *mmu_reset_needed |= vcpu->arch.efer != sregs->efer; static_call(kvm_x86_set_efer)(vcpu, sregs->efer); - mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0; + *mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0; static_call(kvm_x86_set_cr0)(vcpu, sregs->cr0); vcpu->arch.cr0 = sregs->cr0; - mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4; + *mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4; static_call(kvm_x86_set_cr4)(vcpu, sregs->cr4); - idx = srcu_read_lock(&vcpu->kvm->srcu); - if (is_pae_paging(vcpu)) { - load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)); - mmu_reset_needed = 1; - } - srcu_read_unlock(&vcpu->kvm->srcu, idx); - - if (mmu_reset_needed) - kvm_mmu_reset_context(vcpu); - kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS); kvm_set_segment(vcpu, &sregs->ds, VCPU_SREG_DS); kvm_set_segment(vcpu, &sregs->es, VCPU_SREG_ES); @@ -10017,8 +10051,39 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) sregs->cs.selector == 0xf000 && sregs->cs.base == 0xffff0000 && !is_protmode(vcpu)) vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; +out: + return ret; +} + +static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) +{ + int idx, pending_vec, max_bits; + int mmu_reset_needed = 0; + int ret = __set_sregs_common(vcpu, sregs, &mmu_reset_needed); + + if (ret) + return ret; + + if (vcpu->arch.guest_state_protected) + return 0; + + idx = srcu_read_lock(&vcpu->kvm->srcu); + if (is_pae_paging(vcpu)) { + load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)); + mmu_reset_needed = 1; + + /* If we are going to enter a nested guest, we had just + * loaded wrong PDPTRs, thus we need to reload them + * on guest mode entry + */ + + vcpu->arch.pdptr_reload_on_nesting_needed = true; + } + srcu_read_unlock(&vcpu->kvm->srcu, idx); + + if (mmu_reset_needed) + kvm_mmu_reset_context(vcpu); -skip_protected_regs: max_bits = KVM_NR_INTERRUPTS; pending_vec = find_first_bit( (const unsigned long *)sregs->interrupt_bitmap, max_bits); @@ -10028,10 +10093,36 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) } kvm_make_request(KVM_REQ_EVENT, vcpu); + return 0; +} - ret = 0; -out: - return ret; +static int __set_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2) +{ + int mmu_reset_needed = 0; + int i, ret; + + if (sregs2->flags & ~KVM_SREGS2_FLAGS_PDPTRS_VALID) + return -EINVAL; + + ret = __set_sregs_common(vcpu, (struct kvm_sregs *)sregs2, &mmu_reset_needed); + if (ret || vcpu->arch.guest_state_protected) + return ret; + + if (sregs2->flags & KVM_SREGS2_FLAGS_PDPTRS_VALID) { + + if (!is_pae_paging(vcpu)) + return -EINVAL; + + for (i = 0 ; i < 4 ; i++) + kvm_pdptr_write(vcpu, i, sregs2->pdptrs[i]); + + kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR); + mmu_reset_needed = 1; + } + + if (mmu_reset_needed) + kvm_mmu_reset_context(vcpu); + return 0; } int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 7dc1c217704f..156f2f751893 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1082,6 +1082,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_SGX_ATTRIBUTE 196 #define KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 197 #define KVM_CAP_EXIT_HYPERCALL 198 +#define KVM_CAP_SREGS2 199 #ifdef KVM_CAP_IRQ_ROUTING @@ -1620,6 +1621,9 @@ struct kvm_xen_hvm_attr { #define KVM_XEN_VCPU_GET_ATTR _IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr) #define KVM_XEN_VCPU_SET_ATTR _IOW(KVMIO, 0xcb, struct kvm_xen_vcpu_attr) +#define KVM_GET_SREGS2 _IOR(KVMIO, 0xcc, struct kvm_sregs2) +#define KVM_SET_SREGS2 _IOW(KVMIO, 0xcd, struct kvm_sregs2) + struct kvm_xen_vcpu_attr { __u16 type; __u16 pad[3];