| Message ID | 3cc8bfca-be9e-cde8-c481-657ef33de7f2@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | docs: correct "gnttab=" documented default | expand |
Hi Jan, On 28/02/2022 10:19, Jan Beulich wrote: > Defaults differ for Arm and x86, not the least because of v2 not even > being security supported on Arm. > > Also drop a bogus sentence from gnttab_max_maptrack_frames, which was > presumably mistakenly cloned from gnttab_max_frames (albeit even there > what is being said is neither very precise nor very useful imo). > > Signed-off-by: Jan Beulich <jbeulich@suse.com> > > --- a/docs/misc/xen-command-line.pandoc > +++ b/docs/misc/xen-command-line.pandoc > @@ -1177,7 +1177,8 @@ Specify which console gdbstub should use > ### gnttab > > `= List of [ max-ver:<integer>, transitive=<bool>, transfer=<bool> ]` > > -> Default: `gnttab=max-ver:2,transitive,transfer` > +> Default (Arm): `gnttab=max-ver:1` > +> Default (x86): `gnttab=max-ver:2,transitive,transfer` AFAICT, the default would not be correct on x86 when CONFIG_PV=n because transfer is not available. Cheers,
On 28.02.2022 15:02, Julien Grall wrote: > On 28/02/2022 10:19, Jan Beulich wrote: >> Defaults differ for Arm and x86, not the least because of v2 not even >> being security supported on Arm. >> >> Also drop a bogus sentence from gnttab_max_maptrack_frames, which was >> presumably mistakenly cloned from gnttab_max_frames (albeit even there >> what is being said is neither very precise nor very useful imo). >> >> Signed-off-by: Jan Beulich <jbeulich@suse.com> >> >> --- a/docs/misc/xen-command-line.pandoc >> +++ b/docs/misc/xen-command-line.pandoc >> @@ -1177,7 +1177,8 @@ Specify which console gdbstub should use >> ### gnttab >> > `= List of [ max-ver:<integer>, transitive=<bool>, transfer=<bool> ]` >> >> -> Default: `gnttab=max-ver:2,transitive,transfer` >> +> Default (Arm): `gnttab=max-ver:1` >> +> Default (x86): `gnttab=max-ver:2,transitive,transfer` > > AFAICT, the default would not be correct on x86 when CONFIG_PV=n because > transfer is not available. I can certainly split it in two x86 lines, one for PV and one for HVM. I would not have thought I need to go that far, though. Jan
Hi Jan, On 28/02/2022 14:32, Jan Beulich wrote: > On 28.02.2022 15:02, Julien Grall wrote: >> On 28/02/2022 10:19, Jan Beulich wrote: >>> Defaults differ for Arm and x86, not the least because of v2 not even >>> being security supported on Arm. >>> >>> Also drop a bogus sentence from gnttab_max_maptrack_frames, which was >>> presumably mistakenly cloned from gnttab_max_frames (albeit even there >>> what is being said is neither very precise nor very useful imo). >>> >>> Signed-off-by: Jan Beulich <jbeulich@suse.com> >>> >>> --- a/docs/misc/xen-command-line.pandoc >>> +++ b/docs/misc/xen-command-line.pandoc >>> @@ -1177,7 +1177,8 @@ Specify which console gdbstub should use >>> ### gnttab >>> > `= List of [ max-ver:<integer>, transitive=<bool>, transfer=<bool> ]` >>> >>> -> Default: `gnttab=max-ver:2,transitive,transfer` >>> +> Default (Arm): `gnttab=max-ver:1` >>> +> Default (x86): `gnttab=max-ver:2,transitive,transfer` >> >> AFAICT, the default would not be correct on x86 when CONFIG_PV=n because >> transfer is not available. > > I can certainly split it in two x86 lines, one for PV and one for HVM. > I would not have thought I need to go that far, though. I thought I would mention it because to me it feels odd to correct the default on Arm but keep the x86 one potentially inacurrate. Anyway, I am ok if you prefer to keep it like that. This is already an improvement for Arm: Acked-by: Julien Grall <jgrall@amazon.com> Cheers,
--- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -1177,7 +1177,8 @@ Specify which console gdbstub should use ### gnttab > `= List of [ max-ver:<integer>, transitive=<bool>, transfer=<bool> ]` -> Default: `gnttab=max-ver:2,transitive,transfer` +> Default (Arm): `gnttab=max-ver:1` +> Default (x86): `gnttab=max-ver:2,transitive,transfer` Control various aspects of the grant table behaviour available to guests. @@ -1217,8 +1218,6 @@ Specify the maximum number of frames to maptrack array. This value is an upper boundary of the per-domain value settable via Xen tools. -Dom0 is using this value for sizing its maptrack table. - ### global-pages = <boolean>
Defaults differ for Arm and x86, not the least because of v2 not even being security supported on Arm. Also drop a bogus sentence from gnttab_max_maptrack_frames, which was presumably mistakenly cloned from gnttab_max_frames (albeit even there what is being said is neither very precise nor very useful imo). Signed-off-by: Jan Beulich <jbeulich@suse.com>