From bfcf83b1444d90f6e680a0dde0916f3b289b5066 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Thu, 24 Aug 2017 03:35:11 -0700 Subject: [PATCH] KVM: nVMX: Fix trying to cancel vmlauch/vmresume MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit ------------[ cut here ]------------ WARNING: CPU: 7 PID: 3861 at /home/kernel/ssd/kvm/arch/x86/kvm//vmx.c:11299 nested_vmx_vmexit+0x176e/0x1980 [kvm_intel] CPU: 7 PID: 3861 Comm: qemu-system-x86 Tainted: G W OE 4.13.0-rc4+ #11 RIP: 0010:nested_vmx_vmexit+0x176e/0x1980 [kvm_intel] Call Trace: ? kvm_multiple_exception+0x149/0x170 [kvm] ? handle_emulation_failure+0x79/0x230 [kvm] ? load_vmcs12_host_state+0xa80/0xa80 [kvm_intel] ? check_chain_key+0x137/0x1e0 ? reexecute_instruction.part.168+0x130/0x130 [kvm] nested_vmx_inject_exception_vmexit+0xb7/0x100 [kvm_intel] ? nested_vmx_inject_exception_vmexit+0xb7/0x100 [kvm_intel] vmx_queue_exception+0x197/0x300 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x1b0c/0x2c90 [kvm] ? kvm_arch_vcpu_runnable+0x220/0x220 [kvm] ? preempt_count_sub+0x18/0xc0 ? restart_apic_timer+0x17d/0x300 [kvm] ? kvm_lapic_restart_hv_timer+0x37/0x50 [kvm] ? kvm_arch_vcpu_load+0x1d8/0x350 [kvm] kvm_vcpu_ioctl+0x4e4/0x910 [kvm] ? kvm_vcpu_ioctl+0x4e4/0x910 [kvm] ? kvm_dev_ioctl+0xbe0/0xbe0 [kvm] The flag "nested_run_pending", which can override the decision of which should run next, L1 or L2. nested_run_pending=1 means that we *must* run L2 next, not L1. This is necessary in particular when L1 did a VMLAUNCH of L2 and therefore expects L2 to be run (and perhaps be injected with an event it specified, etc.). Nested_run_pending is especially intended to avoid switching to L1 in the injection decision-point. This can be handled just like the other cases in vmx_check_nested_events, instead of having a special case in vmx_queue_exception. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e9e5f4fd834f..e0d2ca092788 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2472,15 +2472,14 @@ static void nested_vmx_inject_exception_vmexit(struct kvm_vcpu *vcpu, * KVM wants to inject page-faults which it got to the guest. This function * checks whether in a nested guest, we need to inject them to L1 or L2. */ -static int nested_vmx_check_exception(struct kvm_vcpu *vcpu) +static int nested_vmx_check_exception(struct kvm_vcpu *vcpu, unsigned long *exit_qual) { struct vmcs12 *vmcs12 = get_vmcs12(vcpu); unsigned int nr = vcpu->arch.exception.nr; if (nr == PF_VECTOR) { if (vcpu->arch.exception.nested_apf) { - nested_vmx_inject_exception_vmexit(vcpu, - vcpu->arch.apf.nested_apf_token); + *exit_qual = vcpu->arch.apf.nested_apf_token; return 1; } /* @@ -2494,16 +2493,15 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu) */ if (nested_vmx_is_page_fault_vmexit(vmcs12, vcpu->arch.exception.error_code)) { - nested_vmx_inject_exception_vmexit(vcpu, vcpu->arch.cr2); + *exit_qual = vcpu->arch.cr2; return 1; } } else { - unsigned long exit_qual = 0; - if (nr == DB_VECTOR) - exit_qual = vcpu->arch.dr6; - if (vmcs12->exception_bitmap & (1u << nr)) { - nested_vmx_inject_exception_vmexit(vcpu, exit_qual); + if (nr == DB_VECTOR) + *exit_qual = vcpu->arch.dr6; + else + *exit_qual = 0; return 1; } } @@ -2516,14 +2514,9 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu) struct vcpu_vmx *vmx = to_vmx(vcpu); unsigned nr = vcpu->arch.exception.nr; bool has_error_code = vcpu->arch.exception.has_error_code; - bool reinject = vcpu->arch.exception.injected; u32 error_code = vcpu->arch.exception.error_code; u32 intr_info = nr | INTR_INFO_VALID_MASK; - if (!reinject && is_guest_mode(vcpu) && - nested_vmx_check_exception(vcpu)) - return; - if (has_error_code) { vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code); intr_info |= INTR_INFO_DELIVER_CODE_MASK; @@ -11011,10 +11004,20 @@ static void vmcs12_save_pending_event(struct kvm_vcpu *vcpu, static int vmx_check_nested_events(struct kvm_vcpu *vcpu, bool external_intr) { struct vcpu_vmx *vmx = to_vmx(vcpu); + unsigned long exit_qual; if (kvm_event_needs_reinjection(vcpu)) return -EBUSY; + if (vcpu->arch.exception.pending && + nested_vmx_check_exception(vcpu, &exit_qual)) { + if (vmx->nested.nested_run_pending) + return -EBUSY; + nested_vmx_inject_exception_vmexit(vcpu, exit_qual); + vcpu->arch.exception.pending = false; + return 0; + } + if (nested_cpu_has_preemption_timer(get_vmcs12(vcpu)) && vmx->nested.preemption_timer_expired) { if (vmx->nested.nested_run_pending) -- 2.20.1