Kyle Moffett wrote: > On Sun, Apr 19, 2009 at 9:19 PM, Huang Ying <ying.huang@xxxxxxxxx> wrote: > >> On Sat, 2009-04-18 at 23:54 +0800, Anthony Liguori wrote: >> >>> Huang Ying wrote: >>> >>>> The related MSRs are emulated. MCE capability is exported via >>>> extension KVM_CAP_MCE and ioctl KVM_X86_GET_MCE_CAP_SUPPORTED. A new >>>> vcpu ioctl command KVM_X86_SETUP_MCE is used to setup MCE emulation >>>> such as the mcg_cap. MCE is injected via vcpu ioctl command >>>> KVM_X86_SET_MCE. Extended machine-check state (MCG_EXT_P) and CMCI are >>>> not simulated. >>>> >>>> >>> Maybe I'm missing something, but couldn't this be implemented entirely >>> within userspace? There's nothing VT/SVM specific about this. If the >>> issue is setting these MSRs from userspace via KVM_SET_MSRS isn't >>> enough, perhaps we should add userspace MSR handling. >>> >>> Also, if you implement the MSR logic in userspace, it's pretty simple to >>> make it work in the non-TCG case which will be a requirement for >>> upstream merging. >>> >> There is more logic than just KVM_SET_MSRS, such as BANK reporting >> disabling, overwriting rules, triple fault for UC MCE during MCIP. >> Although these logic can be implemented in user space, I think put them >> in kernel space is easy to be understood. And the code is pretty short. >> > > IMO the main reason to put this in kernel-space would be to make it > possible to automatically forward some MCE errors generated by the > real hardware (RAM ECC errors for example) down into the VM. Right > now I suppose you could do that with the patches to forward RAM-based > hard MCEs to userspace using SIGSEGV and handling the SIGSEGV in > userspace, but that seems more fragile to me. > FWIW: I would be looking for a way to generate MCE to report async vbus faults via my SHM_SIGNAL_FAULT() mechanism, so I am very much in favor of this support being in-kernel. -Greg > Cheers, > Kyle Moffett > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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