On Tue, 20 Aug 2024, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.igles...@amd.com> > > Add SMP support for Xen PVH ARM guests. > Create ms->smp.max_cpus ioreq servers to handle hotplug. > > Note that ms->smp.max_cpus will be passed to us by the > user (Xen tools) set to the guests maxvcpus. > > The value in mc->max_cpus is an absolute maximum for the > -smp option and won't be used to setup ioreq servers unless > the user explicitly specifies it with -smp. > > If the user doesn't pass -smp on the command-line, smp.cpus > and smp.max_cpus will default to 1. > > Signed-off-by: Edgar E. Iglesias <edgar.igles...@amd.com>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org> > --- > hw/arm/xen_arm.c | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/hw/arm/xen_arm.c b/hw/arm/xen_arm.c > index 5f75cc3779..fda65d0d8d 100644 > --- a/hw/arm/xen_arm.c > +++ b/hw/arm/xen_arm.c > @@ -173,7 +173,7 @@ static void xen_arm_init(MachineState *machine) > > xen_init_ram(machine); > > - xen_register_ioreq(xam->state, machine->smp.cpus, &xen_memory_listener); > + xen_register_ioreq(xam->state, machine->smp.max_cpus, > &xen_memory_listener); > > xen_create_virtio_mmio_devices(xam); > > @@ -218,7 +218,26 @@ static void xen_arm_machine_class_init(ObjectClass *oc, > void *data) > MachineClass *mc = MACHINE_CLASS(oc); > mc->desc = "Xen PVH ARM machine"; > mc->init = xen_arm_init; > - mc->max_cpus = 1; > + > + /* > + * mc->max_cpus holds the MAX value allowed in the -smp command-line > opts. > + * > + * 1. If users don't pass any -smp option: > + * ms->smp.cpus will default to 1. > + * ms->smp.max_cpus will default to 1. > + * > + * 2. If users pass -smp X: > + * ms->smp.cpus will be set to X. > + * ms->smp.max_cpus will also be set to X. > + * > + * 3. If users pass -smp X,maxcpus=Y: > + * ms->smp.cpus will be set to X. > + * ms->smp.max_cpus will be set to Y. > + * > + * In scenarios 2 and 3, if X or Y are set to something larger than > + * mc->max_cpus, QEMU will bail out with an error message. > + */ > + mc->max_cpus = GUEST_MAX_VCPUS; > mc->default_machine_opts = "accel=xen"; > /* Set explicitly here to make sure that real ram_size is passed */ > mc->default_ram_size = 0; > -- > 2.43.0 >
