On Wed, Jan 20, 2021 at 05:49:09PM -0500, Boris Ostrovsky wrote: > This option allows guest administrator specify what should happen when > guest accesses an MSR which is not explicitly emulated by the hypervisor. > > Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com> > --- > docs/man/xl.cfg.5.pod.in | 20 +++++++++++++++++++- > tools/libs/light/libxl_types.idl | 7 +++++++ > tools/xl/xl_parse.c | 7 +++++++ > 3 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in > index c8e017f950de..96ce97c42cab 100644 > --- a/docs/man/xl.cfg.5.pod.in > +++ b/docs/man/xl.cfg.5.pod.in > @@ -2044,7 +2044,25 @@ Do not provide a VM generation ID. > See also "Virtual Machine Generation ID" by Microsoft: > > L<https://docs.microsoft.com/en-us/windows/win32/hyperv_v2/virtual-machine-generation-identifier> > > -=back > +=over > + > +=item B<ignore_msrs="STRING"> > + > +Determine hypervisor behavior on accesses to MSRs that are not emulated by > the hypervisor. > + > +=over 4 > + > +=item B<never> > + > +Issue a warning to the log and #GP to the guest. This is default. > + > +=item B<silent> > + > +MSR reads return 0, MSR writes are ignored. No warnings to the log. > + > +=item B<verbose> > + > +Similar to B<silent> but a warning is written.
Would it make sense to allow for this option to be more fine-grained in the future? Not that you need to implement the full thing now, but maybe we could have something like: " =item B<ignore_msrs=[ "MSR_RANGE, "MSR_RANGE", ..]> Specify a list of MSR ranges that will be ignored by the hypervisor: reads will return zeros and writes will be discarded without raising a #GP. Each MSR_RANGE is given in hexadecimal format and may be a range, e.g. c00102f0-c00102f1 (inclusive), or a single MSR, e.g. c00102f1. " Then you can print the messages in the hypervisor using a guest log level and modify it on demand in order to get more verbose output? I don't think selecting whether the messages are printed or not from xl is that helpful as the same could be achieved using guest_loglvl. Also I think it will be fine to only implement: ignore_msrs=[ "0-ffffffff" ] Right now and return an error for any other combination, so that we can get something in soon and expand it later. Thanks, Roger.
