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Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos
From: |
Gonglei (Arei) |
Subject: |
Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos |
Date: |
Wed, 16 Dec 2015 08:26:17 +0000 |
Hi,
> -----Original Message-----
> From: Radim Krcmar [mailto:address@hidden
> Subject: Re: [PATCH] rtc: introduce nmi disable bit handler for cmos
>
> 2015-12-15 05:43-0500, Paolo Bonzini:
> >> Hi Paolo,
> >>
> >> /* for KVM_GET/SET_VCPU_EVENTS */
> >> struct kvm_vcpu_events {
> >> ...
> >> struct {
> >> __u8 injected;
> >> __u8 pending;
> >> __u8 masked;
> >> __u8 pad;
> >> } nmi;
> >> ...
> >>
> >> I found that the nmi.masked property does these enable or disable NMI
> jobs.
> >> So, I think we don't need to add a new bit. Right?
> >
> > nmi.masked says whether the CPU is accepting the NMIs, and is cleared
> > by the next IRET instruction. This is a different thing; it probably
> > shouldn't affect NMI IPIs, and it definitely should remain set until
> > cleared via the RTC. So it should be something like
> >
> > _u8 external_nmi_disabled;
> >
> > or similar.
> >
OK, I see, thanks.
> > *However* I found this in the ICH9 datasheet:
> >
> > The ICH9's I/O APIC can only send interrupts due to interrupts which
> > do not include SMI, NMI or INIT. This means that in IA-32/Intel ® 64
> > based platforms, Front Side Bus interrupt message format delivery
> modes
> > 010 (SMI/PMI), 100 (NMI), and 101 (INIT) as indicated in this section,
> > must not be used and is not supported.
> >
> > In theory the PIIX4 could deliver such messages, but perhaps we could
> > disable them in the KVM IOAPIC. If we do this, there is no need for a
> > change to struct kvm_vcpu_events, because all external NMI sources will
> > be in userspace.
> >
> > Radim, what do you think?
>
> I looked at the 440fx, piix, and 82083aa(ioapic) datasheets and the
> NMI_EN bit doesn't seem to be propagated into the IOAPIC.
> The IOAPIC datasheet doesn't mention a thing about NMI masking and PIIX4
> generates NMI on SERR# or IOCHK# so it seems that the NMI_EN feature
> only changes the behavior of those two ...
>
Currently, Qemu doesn't handle SERR# (bit 7) and IOCHK# (bit 6) of port 0x61.
The
Linux kernel gets the nmi reason when invoke default_do_nmi(), Qemu always
return 0.
Regards,
-Gonglei
> I think it's best to do nothing in KVM.
>
> (q35 guests shouldn't configure IOAPIC to send unsupported messages and
> disabling SMI/NMI/INIT in the in-kernel IOAPIC for piix is risky.)
- [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei, 2015/12/12
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/14
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/15
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/15
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Radim Krcmar, 2015/12/15
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos,
Gonglei (Arei) <=
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/16
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/16
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/16
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/17
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Paolo Bonzini, 2015/12/17
- Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Gonglei (Arei), 2015/12/17
Re: [Qemu-devel] [PATCH] rtc: introduce nmi disable bit handler for cmos, Eduardo Habkost, 2015/12/14