KVM: PPC: Book3S HV: XIVE: Allow userspace to set the # of VPs
Add a new attribute to both XIVE and XICS-on-XIVE KVM devices so that
userspace can tell how many interrupt servers it needs. If a VM needs
less than the current default of KVM_MAX_VCPUS (2048), we can allocate
less VPs in OPAL. Combined with a core stride (VSMT) that matches the
number of guest threads per core, this may substantially increases the
number of VMs that can run concurrently with an in-kernel XIVE device.
Since the legacy XIVE KVM device is exposed to userspace through the
XICS KVM API, a new attribute group is added to it for this purpose.
While here, fix the syntax of the existing KVM_DEV_XICS_GRP_SOURCES
in the XICS documentation.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index 6c35b3d..66858b7 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -1911,6 +1911,11 @@ static int xive_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
switch (attr->group) {
case KVM_DEV_XICS_GRP_SOURCES:
return xive_set_source(xive, attr->attr, attr->addr);
+ case KVM_DEV_XICS_GRP_CTRL:
+ switch (attr->attr) {
+ case KVM_DEV_XICS_NR_SERVERS:
+ return kvmppc_xive_set_nr_servers(xive, attr->addr);
+ }
}
return -ENXIO;
}
@@ -1936,6 +1941,11 @@ static int xive_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
attr->attr < KVMPPC_XICS_NR_IRQS)
return 0;
break;
+ case KVM_DEV_XICS_GRP_CTRL:
+ switch (attr->attr) {
+ case KVM_DEV_XICS_NR_SERVERS:
+ return 0;
+ }
}
return -ENXIO;
}