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
