lkml.org 
[lkml]   [2018]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH 1/5] x86/ibrs: Introduce native_rdmsrl, and native_wrmsrl
    Date
    From
    On Thu, 2018-01-11 at 21:03 -0800, Dave Hansen wrote:
    > On 01/11/2018 07:01 PM, Raj, Ashok wrote:
    > > On Thu, Jan 11, 2018 at 06:20:13PM -0800, Andy Lutomirski wrote:
    > >> On Thu, Jan 11, 2018 at 5:52 PM, Raj, Ashok <ashok.raj@intel.com> wrote:
    > >>>>
    > >>>> What's wrong with native_read_msr()?
    > >>>
    > >>> Yes, i think i should have added to msr.h. The names didn't read as a
    > >>> pair, one was native_read_msr, wrmsrl could be taken over when paravirt is
    > >>> defined?
    > >>
    > >> Why do you need to override paravirt?
    > > 
    > > The idea was since these MSR's are passed through we shouldn't need to 
    > > handle them any differently. Also its best to do this as soon as possible
    > > and avoid longer paths to get this barrier to hardware.
    >
    > We were also worried about the indirect calls that are part of the
    > paravirt interfaces when retpolines are not in place.

    I have repeatedly been told that these go away, and are converted to
    direct branches by the time the kernel is running userspace.

    I suppose I really ought to validate that with qemu -d in_asm or
    something. I couldn't see it in the code... but I haven't looked that
    hard yet.[unhandled content-type:application/x-pkcs7-signature]
    \
     
     \ /
      Last update: 2018-01-14 23:25    [W:2.321 / U:0.180 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site