[PATCH 0/15] Hypervisor-mode KVM on POWER7 and PPC970

Paul Mackerras paulus at samba.org
Sat Jun 18 18:27:05 EST 2011


The following series of patches enable KVM to exploit the hardware
hypervisor mode on 64-bit Power ISA Book3S machines.  At present,
POWER7 and PPC970 processors are supported.  (Note that the PPC970
processors in Apple G5 machines don't have a usable hypervisor mode
and are not supported by these patches.)

Running the KVM host in hypervisor mode means that the guest can use
both supervisor mode and user mode.  That means that the guest can
execute supervisor-privilege instructions and access supervisor-
privilege registers.  In addition the hardware directs most exceptions
to the guest.  Thus we don't need to emulate any instructions in the
host.  Generally, the only times we need to exit the guest are when it
does a hypercall or when an external interrupt or host timer
(decrementer) interrupt occurs.

The focus of this KVM implementation is to run guests that use the
PAPR (Power Architecture Platform Requirements) paravirtualization
interface, which is the interface supplied by PowerVM on IBM pSeries
machines.  Currently the "pseries" machine type in qemu is only
supported by book3s_hv KVM, and book3s_hv KVM only supports the
"pseries" machine type.  That will hopefully change in future.

These patches are against Alex Graf's kvm-ppc-next branch.

Paul.


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