On 23.05.2023 09:43, Luca Fancellu wrote: > Add a command line parameter to allow Dom0 the use of SVE resources, > the command line parameter sve=<integer>, sub argument of dom0=, > controls the feature on this domain and sets the maximum SVE vector > length for Dom0. > > Add a new function, parse_signed_integer(), to parse an integer > command line argument. > > Signed-off-by: Luca Fancellu <luca.fance...@arm.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com> # !arm > --- a/docs/misc/xen-command-line.pandoc > +++ b/docs/misc/xen-command-line.pandoc > @@ -777,9 +777,9 @@ Specify the bit width of the DMA heap. > > ### dom0 > = List of [ pv | pvh, shadow=<bool>, verbose=<bool>, > - cpuid-faulting=<bool>, msr-relaxed=<bool> ] > + cpuid-faulting=<bool>, msr-relaxed=<bool> ] (x86) > > - Applicability: x86 > + = List of [ sve=<integer> ] (Arm) While in the text below you mention this is Arm64 only, I think the tag here would better express this as well. > @@ -838,6 +838,22 @@ Controls for how dom0 is constructed on x86 systems. > > If using this option is necessary to fix an issue, please report a bug. > > +Enables features on dom0 on Arm systems. > + > +* The `sve` integer parameter enables Arm SVE usage for Dom0 domain and > sets > + the maximum SVE vector length, the option is applicable only to AArch64 > + guests. Why "guests"? Does the option affect more than Dom0? > + A value equal to 0 disables the feature, this is the default value. > + Values below 0 means the feature uses the maximum SVE vector length > + supported by hardware, if SVE is supported. > + Values above 0 explicitly set the maximum SVE vector length for Dom0, > + allowed values are from 128 to maximum 2048, being multiple of 128. > + Please note that when the user explicitly specifies the value, if that > value > + is above the hardware supported maximum SVE vector length, the domain > + creation will fail and the system will stop, the same will occur if the > + option is provided with a non zero value, but the platform doesn't > support > + SVE. Assuming this also covers the -1 case, I wonder if that isn't a little too strict. "Maximum supported" imo can very well be 0. Jan
