From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934749AbdKCAvR (ORCPT ); Thu, 2 Nov 2017 20:51:17 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:56339 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932398AbdKCAvB (ORCPT ); Thu, 2 Nov 2017 20:51:01 -0400 X-Google-Smtp-Source: ABhQp+RbuYrLBkOfKJQEKHwKf4IfR8WfaS6G76CE8dJmjGdS/B8cH+n6F30ht236kaLaRvDs8c9q9Q== From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Wanpeng Li , Jim Mattson Subject: [PATCH v5 3/3] KVM: nVMX: Fix mmu context after VMLAUNCH/VMRESUME failure Date: Thu, 2 Nov 2017 17:50:49 -0700 Message-Id: <1509670249-4907-3-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1509670249-4907-1-git-send-email-wanpeng.li@hotmail.com> References: <1509670249-4907-1-git-send-email-wanpeng.li@hotmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Commit 4f350c6dbcb (kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly) can result in L1(run kvm-unit-tests/run_tests.sh vmx_controls in L1) null pointer deference and also L0 calltrace when EPT=0 on both L0 and L1. In L1: BUG: unable to handle kernel paging request at ffffffffc015bf8f IP: vmx_vcpu_run+0x202/0x510 [kvm_intel] PGD 146e13067 P4D 146e13067 PUD 146e15067 PMD 3d2686067 PTE 3d4af9161 Oops: 0003 [#1] PREEMPT SMP CPU: 2 PID: 1798 Comm: qemu-system-x86 Not tainted 4.14.0-rc4+ #6 RIP: 0010:vmx_vcpu_run+0x202/0x510 [kvm_intel] Call Trace: WARNING: kernel stack frame pointer at ffffb86f4988bc18 in qemu-system-x86:1798 has bad value 0000000000000002 In L0: -----------[ cut here ]------------ WARNING: CPU: 6 PID: 4460 at /home/kernel/linux/arch/x86/kvm//vmx.c:9845 vmx_inject_page_fault_nested+0x130/0x140 [kvm_intel] CPU: 6 PID: 4460 Comm: qemu-system-x86 Tainted: G OE 4.14.0-rc7+ #25 RIP: 0010:vmx_inject_page_fault_nested+0x130/0x140 [kvm_intel] Call Trace: paging64_page_fault+0x500/0xde0 [kvm] ? paging32_gva_to_gpa_nested+0x120/0x120 [kvm] ? nonpaging_page_fault+0x3b0/0x3b0 [kvm] ? __asan_storeN+0x12/0x20 ? paging64_gva_to_gpa+0xb0/0x120 [kvm] ? paging64_walk_addr_generic+0x11a0/0x11a0 [kvm] ? lock_acquire+0x2c0/0x2c0 ? vmx_read_guest_seg_ar+0x97/0x100 [kvm_intel] ? vmx_get_segment+0x2a6/0x310 [kvm_intel] ? sched_clock+0x1f/0x30 ? check_chain_key+0x137/0x1e0 ? __lock_acquire+0x83c/0x2420 ? kvm_multiple_exception+0xf2/0x220 [kvm] ? debug_check_no_locks_freed+0x240/0x240 ? debug_smp_processor_id+0x17/0x20 ? __lock_is_held+0x9e/0x100 kvm_mmu_page_fault+0x90/0x180 [kvm] kvm_handle_page_fault+0x15c/0x310 [kvm] ? __lock_is_held+0x9e/0x100 handle_exception+0x3c7/0x4d0 [kvm_intel] vmx_handle_exit+0x103/0x1010 [kvm_intel] ? kvm_arch_vcpu_ioctl_run+0x1628/0x2e20 [kvm] The commit avoids to load host state of vmcs12 as vmcs01's guest state since vmcs12 is not modified (except for the VM-instruction error field) if the checking of vmcs control area fails. However, the mmu context is switched to nested mmu in prepare_vmcs02() and it will not be reloaded since load_vmcs12_host_state() is skipped when nested VMLAUNCH/VMRESUME fails. This patch fixes it by reloading mmu context when nested VMLAUNCH/VMRESUME fails. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Jim Mattson Signed-off-by: Wanpeng Li --- v3 -> v4: * move it to a new function load_vmcs12_mmu_host_state arch/x86/kvm/vmx.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 6cf3972..8aefb91 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11259,6 +11259,24 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, kvm_clear_interrupt_queue(vcpu); } +static void load_vmcs12_mmu_host_state(struct kvm_vcpu *vcpu, + struct vmcs12 *vmcs12) +{ + u32 entry_failure_code; + + nested_ept_uninit_mmu_context(vcpu); + + /* + * Only PDPTE load can fail as the value of cr3 was checked on entry and + * couldn't have changed. + */ + if (nested_vmx_load_cr3(vcpu, vmcs12->host_cr3, false, &entry_failure_code)) + nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_PDPTE_FAIL); + + if (!enable_ept) + vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault; +} + /* * A part of what we need to when the nested L2 guest exits and we want to * run its L1 parent, is to reset L1's guest state to the host state specified @@ -11272,7 +11290,6 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) { struct kvm_segment seg; - u32 entry_failure_code; if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_EFER) vcpu->arch.efer = vmcs12->host_ia32_efer; @@ -11299,17 +11316,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, vcpu->arch.cr4_guest_owned_bits = ~vmcs_readl(CR4_GUEST_HOST_MASK); vmx_set_cr4(vcpu, vmcs12->host_cr4); - nested_ept_uninit_mmu_context(vcpu); - - /* - * Only PDPTE load can fail as the value of cr3 was checked on entry and - * couldn't have changed. - */ - if (nested_vmx_load_cr3(vcpu, vmcs12->host_cr3, false, &entry_failure_code)) - nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_PDPTE_FAIL); - - if (!enable_ept) - vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault; + load_vmcs12_mmu_host_state(vcpu, vmcs12); if (enable_vpid) { /* @@ -11539,6 +11546,9 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, * accordingly. */ nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); + + load_vmcs12_mmu_host_state(vcpu, vmcs12); + /* * The emulated instruction was already skipped in * nested_vmx_run, but the updated RIP was never -- 2.7.4