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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [BUG] Emulation issues
El 30/07/15 a les 12.59, Paul Durrant ha escrit:
>> -----Original Message-----
> [big snip]
>> Sorry, missed that in the noise. So, the problem is that there is no
>> in-flight I/O
>> even though pio completion is being attempted. Something has got out of
>> sync.
>>
>
> I think I understand what may be happening... The code in hvmemul_do_io()
> basically expects to be called either to issue an I/O or to extract info from
> a completed one. However it is being called unconditionally (in the PIO case)
> out of hvm_do_resume, rather than only if the in-flight I/O state has been
> updated to STATE_IORESP_READY.
>
> Can you try this patch (also containing my previous debug patch)?
>
> diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
> index 30acb78..1bc3cc9 100644
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -145,6 +145,8 @@ static int hvmemul_do_io(
> return X86EMUL_UNHANDLEABLE;
> goto finish_access;
> default:
> + gprintk(XENLOG_ERR, "weird emulation state %u\n",
> + vio->io_req.state);
> return X86EMUL_UNHANDLEABLE;
> }
>
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index ec1d797..a476271 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -472,7 +472,6 @@ void hvm_do_resume(struct vcpu *v)
> struct hvm_vcpu_io *vio = &v->arch.hvm_vcpu.hvm_io;
> struct domain *d = v->domain;
> struct hvm_ioreq_server *s;
> - enum hvm_io_completion io_completion;
>
> check_wakeup_from_wait();
>
> @@ -499,33 +498,38 @@ void hvm_do_resume(struct vcpu *v)
> }
> }
>
> - io_completion = vio->io_completion;
> - vio->io_completion = HVMIO_no_completion;
> -
> - switch ( io_completion )
> - {
> - case HVMIO_no_completion:
> - break;
> - case HVMIO_mmio_completion:
> - handle_mmio();
> - break;
> - case HVMIO_pio_completion:
> - (void)handle_pio(vio->io_req.addr, vio->io_req.size,
> - vio->io_req.dir);
> - break;
> - case HVMIO_realmode_completion:
> + if ( vio->io_req.state == STATE_IORESP_READY )
> {
> - struct hvm_emulate_ctxt ctxt;
> + enum hvm_io_completion io_completion;
>
> - hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
> - vmx_realmode_emulate_one(&ctxt);
> - hvm_emulate_writeback(&ctxt);
> + io_completion = vio->io_completion;
> + vio->io_completion = HVMIO_no_completion;
>
> - break;
> - }
> - default:
> - ASSERT_UNREACHABLE();
> - break;
> + switch ( io_completion )
> + {
> + case HVMIO_no_completion:
> + break;
> + case HVMIO_mmio_completion:
> + handle_mmio();
> + break;
> + case HVMIO_pio_completion:
> + (void)handle_pio(vio->io_req.addr, vio->io_req.size,
> + vio->io_req.dir);
> + break;
> + case HVMIO_realmode_completion:meet
> + {
> + struct hvm_emulate_ctxt ctxt;
> +
> + hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
> + vmx_realmode_emulate_one(&ctxt);
> + hvm_emulate_writeback(&ctxt);
> +
> + break;
> + }
> + default:
> + ASSERT_UNREACHABLE();
> + break;
> + }
> }
>
> if ( unlikely(d->arch.event_write_data) )
> @@ -2747,6 +2751,7 @@ int hvm_send_ioreq(struct hvm_ioreq_server *s, ioreq_t
> *proto_p,
> }
> }
>
> + gprintk(XENLOG_ERR, "unable to contact device model\n");
> return X86EMUL_UNHANDLEABLE;
> }
With this (and only this) patch applied I get the following output:
(XEN) irq.c:276: Dom18 PCI link 2 changed 11 -> 0
(XEN) irq.c:276: Dom18 PCI link 3 changed 5 -> 0
(XEN) irq.c:276: Dom19 PCI link 0 changed 5 -> 0
(XEN) irq.c:276: Dom19 PCI link 1 changed 10 -> 0
(XEN) irq.c:276: Dom19 PCI link 2 changed 11 -> 0
(XEN) irq.c:276: Dom19 PCI link 3 changed 5 -> 0
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
(XEN) d19v0 weird emulation state 1
(XEN) io.c:165:d19v0 Weird HVM ioemulation status 1.
(XEN) domain_crash called from io.c:166
Roger.
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