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Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit |
Date: |
Mon, 16 Nov 2015 10:01:25 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 16/11/15 04:50, Paul Mackerras wrote:
> On Thu, Nov 12, 2015 at 09:09:59AM +0100, Thomas Huth wrote:
>>
>> Shouldn't you also check MSR_ME here first and enter checkstop when
>> machine checks are disabled?
>
> MSR_ME is a hypervisor resource and is not able to be controlled by HV
> KVM guests, or in fact by the OS running on the pseries machine target
> regardless of how it's accelerated or emulated.
>
> What you say would only apply if we had a powernv machine target and
> we were emulating the whole system, and in that case we wouldn't be
> using any hcalls, and we wouldn't be doing FWNMI (or at least not at
> this level).
>
> So the answer is no, MSR_ME will always be set when running in a
> guest, and we don't ever need to checkstop the virtual machine.
Good point, I missed that sentence about the hypervisor resource in the
PowerISA. So QEMU does not have to check this bit here.
But out of curiosity: What happens if a guest disables the ME bit? Is
this checked somewhere or simply ignored?
Thomas
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, (continued)
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Aravinda Prasad, 2015/11/12
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, David Gibson, 2015/11/12
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Aravinda Prasad, 2015/11/12
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, David Gibson, 2015/11/13
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Aravinda Prasad, 2015/11/13
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Paul Mackerras, 2015/11/16
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit,
Thomas Huth <=
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Aravinda Prasad, 2015/11/16
- Re: [Qemu-devel] [PATCH 4/4] target-ppc: Handle NMI guest exit, Paul Mackerras, 2015/11/16
[Qemu-devel] [PATCH 2/4] spapr: Register and handle HCALL to receive updated RTAS region, Aravinda Prasad, 2015/11/11
Re: [Qemu-devel] [PATCH 0/4] target-ppc/spapr: Add FWNMI support in QEMU for PowerKVM guests, David Gibson, 2015/11/11