Re: [Qemu-devel] E5-2620v2 - emulation stop error

Andrey Korolyov
2015-03-31T17:40:44Z

On Tue, Mar 31, 2015 at 7:45 PM, Radim Krčmář <rkrcmar@redhat.com> wrote:
> 2015-03-31 17:56+0300, Andrey Korolyov:
>> > Chasing the culprit this way could take a long time, so a new tracepoint
>> > that shows if 0xef is set on entry would let us guess the bug faster ...
>> >
>> > Please provide a failing trace with the following patch:
>>
>> Thanks, please see below:
>>
>> http://xdel.ru/downloads/kvm-e5v2-issue/new-tracepoint-fail-with-apicv.dat.gz
>
> qemu-system-x86-4022 [006] 255.915978:
> kvm_entry: vcpu 0
> kvm_emulate_insn: f0000:d275: ea 7a d2 00 f0
> kvm_emulate_insn: f0000:d27a: 2e 0f 01 1e f0 6c
> kvm_emulate_insn: f0000:d280: 31 c0
> kvm_emulate_insn: f0000:d282: 8e e0
> kvm_emulate_insn: f0000:d284: 8e e8
> kvm_emulate_insn: f0000:d286: 8e c0
> kvm_emulate_insn: f0000:d288: 8e d8
> kvm_emulate_insn: f0000:d28a: 8e d0
> kvm_entry: vcpu 0
> kvm_0xef: irr clear, isr clear, vmcs 0x0
> kvm_exit: reason EPT_VIOLATION rip 0x8dd0 info 184 0
> kvm_page_fault: address f8dd0 error_code 184
> kvm_entry: vcpu 0
> kvm_0xef: irr clear, isr clear, vmcs 0x0
> kvm_exit: reason EPT_VIOLATION rip 0x76d6 info 184 0
> kvm_page_fault: address f76d6 error_code 184
> kvm_entry: vcpu 0
> kvm_0xef: irr clear, isr clear, vmcs 0x0
> kvm_exit: reason EXCEPTION_NMI rip 0xd331 info 0 80000b0d
> kvm_userspace_exit: reason KVM_EXIT_INTERNAL_ERROR (17)
>
> Ok, nothing obvious here either ... I've desperately added all
> information I know about. Please run it again, thanks.
>
> (The patch has to be applied instead of the previous one.)
> ---
> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
> index 7c7bc8bef21f..f986636ad9d0 100644
> --- a/arch/x86/kvm/trace.h
> +++ b/arch/x86/kvm/trace.h
> @@ -742,6 +742,41 @@ TRACE_EVENT(kvm_emulate_insn,
> #define trace_kvm_emulate_insn_start(vcpu) trace_kvm_emulate_insn(vcpu, 0)
> #define trace_kvm_emulate_insn_failed(vcpu) trace_kvm_emulate_insn(vcpu, 1)
>
> +TRACE_EVENT(kvm_0xef,
> + TP_PROTO(bool irr, bool isr, u32 info, bool on, bool pir, u16 status),
> + TP_ARGS(irr, isr, info, on, pir, status),
> +
> + TP_STRUCT__entry(
> + __field(bool, irr )
> + __field(bool, isr )
> + __field(u32, info)
> + __field(bool, on )
> + __field(bool, pir )
> + __field(u8, rvi )
> + __field(u8, svi )
> + ),
> +
> + TP_fast_assign(
> + __entry->irr = irr;
> + __entry->isr = isr;
> + __entry->info = info;
> + __entry->on = on;
> + __entry->pir = pir;
> + __entry->rvi = status & 0xff;
> + __entry->svi = status >> 8;
> + ),
> +
> + TP_printk("irr %s, isr %s, info 0x%x, on %s, pir %s, rvi 0x%x, svi 0x%x",
> + __entry->irr ? "set " : "clear",
> + __entry->isr ? "set " : "clear",
> + __entry->info,
> + __entry->on ? "set " : "clear",
> + __entry->pir ? "set " : "clear",
> + __entry->rvi,
> + __entry->svi
> + )
> + );
> +
> TRACE_EVENT(
> vcpu_match_mmio,
> TP_PROTO(gva_t gva, gpa_t gpa, bool write, bool gpa_match),
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index eee63dc33d89..b461edc93d53 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -5047,6 +5047,25 @@ static int handle_machine_check(struct kvm_vcpu *vcpu)
> return 1;
> }
>
> +#define VEC_POS(v) ((v) & (32 - 1))
> +#define REG_POS(v) (((v) >> 5) << 4)
> +static inline int apic_test_vector(int vec, void *bitmap)
> +{
> + return test_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
> +}
> +
> +static inline void random_trace(struct kvm_vcpu *vcpu)
> +{
> + struct vcpu_vmx *vmx = to_vmx(vcpu);
> +
> + trace_kvm_0xef(apic_test_vector(0xef, vcpu->arch.apic->regs + APIC_IRR),
> + apic_test_vector(0xef, vcpu->arch.apic->regs + APIC_ISR),
> + vmcs_read32(VM_ENTRY_INTR_INFO_FIELD),
> + test_bit(POSTED_INTR_ON, (unsigned long *)&vmx->pi_desc.control),
> + test_bit(0xef, (unsigned long *)vmx->pi_desc.pir),
> + vmcs_read16(GUEST_INTR_STATUS));
> +}
> +
> static int handle_exception(struct kvm_vcpu *vcpu)
> {
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> @@ -5077,6 +5096,8 @@ static int handle_exception(struct kvm_vcpu *vcpu)
> return 1;
> }
>
> + random_trace(vcpu);
> +
> error_code = 0;
> if (intr_info & INTR_INFO_DELIVER_CODE_MASK)
> error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
> @@ -8143,6 +8164,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
> if (vmx->emulation_required)
> return;
>
> + random_trace(vcpu);
> +
> if (vmx->ple_window_dirty) {
> vmx->ple_window_dirty = false;
> vmcs_write32(PLE_WINDOW, vmx->ple_window);
> @@ -8312,6 +8335,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
> vmx->exit_reason = vmcs_read32(VM_EXIT_REASON);
> trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX);
>
> + random_trace(vcpu);
> +
> /*
> * the KVM_REQ_EVENT optimization bit is only on for one entry, and if
> * we did not inject a still-pending event to L1 now because of
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 32bf19ef3115..a45fa01bd354 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7881,3 +7881,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_intercepts);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_write_tsc_offset);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_ple_window);
> EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_pml_full);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_0xef);

http://xdel.ru/downloads/kvm-e5v2-issue/another-tracepoint-fail-with-apicv.dat.gz

Something a bit more interesting, but the mess is happening just
*after* NMI firing.