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| author | Greg Kurz <groug@kaod.org> | 2019-09-27 13:54:07 +0200 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2019-10-22 16:29:02 +1100 |
| commit | efe5ddcae496b7c7307805d31815df23ba69bf7c (patch) | |
| tree | 34417d20e68a6ae70435a7b6651d70972c3fed1b /Documentation/virt/kvm/devices/xive.txt | |
| parent | 062cfab7069fcb55d77ad5552f29e24178728fa2 (diff) | |
| download | lwn-efe5ddcae496b7c7307805d31815df23ba69bf7c.tar.gz lwn-efe5ddcae496b7c7307805d31815df23ba69bf7c.zip | |
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>
Diffstat (limited to 'Documentation/virt/kvm/devices/xive.txt')
| -rw-r--r-- | Documentation/virt/kvm/devices/xive.txt | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/devices/xive.txt b/Documentation/virt/kvm/devices/xive.txt index 9a24a4525253..f5d1d6b5af61 100644 --- a/Documentation/virt/kvm/devices/xive.txt +++ b/Documentation/virt/kvm/devices/xive.txt @@ -78,6 +78,14 @@ the legacy interrupt mode, referred as XICS (POWER7/8). migrating the VM. Errors: none + 1.3 KVM_DEV_XIVE_NR_SERVERS (write only) + The kvm_device_attr.addr points to a __u32 value which is the number of + interrupt server numbers (ie, highest possible vcpu id plus one). + Errors: + -EINVAL: Value greater than KVM_MAX_VCPU_ID. + -EFAULT: Invalid user pointer for attr->addr. + -EBUSY: A vCPU is already connected to the device. + 2. KVM_DEV_XIVE_GRP_SOURCE (write only) Initializes a new source in the XIVE device and mask it. Attributes: |