lkml.org 
[lkml]   [2009]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] Add MCE support to KVM
    On 04/20/09 13:27, Avi Kivity wrote:
    > Gerd Hoffmann wrote:
    >>>> Well, xenner doesn't do vmcalls, so the page isn't vendor specific.
    >>>
    >>> Well, for true pv (not pv-on-hvm) it wouldn't use the MSR, would it?
    >>
    >> Yes, the MSR is used for pv-on-hvm only.
    >
    > So it isn't relevant for Xenner?

    It is. I still plan to merge xenner into qemu, and also support
    xenstyle pv-on-hvm drivers.

    > That said, I'd like to be able to emulate the Xen HVM hypercalls. But in
    > any case, they hypercall implementation has to be in the kernel,

    No. With Xenner the xen hypercall emulation code lives in guest address
    space.

    > so I
    > don't see why the MSR shouldn't be.

    I don't care that much, but /me thinks it would be easier to handle in
    userspace ...

    > Especially if we need to support
    > tricky bits like continuations.

    Is there any reason to? I *think* xen does it for better scheduling
    latency. But with xen emulation sitting in guest address space we can
    schedule the guest at will anyway.

    >> Same MSR, multiple writes (page number in the low bits).
    >
    > Nasty. The hypervisor has to remember all of the pages, so it can update
    > them for live migration.

    Xenner doesn't need update-on-migration, so there is no need at all to
    remember this. At the end of the day it is just memcpy(guest, data,
    PAGESIZE) triggered by wrmsr.

    cheers,
    Gerd


    \
     
     \ /
      Last update: 2009-04-20 14:23    [W:0.038 / U:1.132 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site