linux/arch/powerpc/kvm/Kconfig
Paul Mackerras b6c295df31 KVM: PPC: Book3S HV: Accumulate timing information for real-mode code
This reads the timebase at various points in the real-mode guest
entry/exit code and uses that to accumulate total, minimum and
maximum time spent in those parts of the code.  Currently these
times are accumulated per vcpu in 5 parts of the code:

* rm_entry - time taken from the start of kvmppc_hv_entry() until
  just before entering the guest.
* rm_intr - time from when we take a hypervisor interrupt in the
  guest until we either re-enter the guest or decide to exit to the
  host.  This includes time spent handling hcalls in real mode.
* rm_exit - time from when we decide to exit the guest until the
  return from kvmppc_hv_entry().
* guest - time spend in the guest
* cede - time spent napping in real mode due to an H_CEDE hcall
  while other threads in the same vcore are active.

These times are exposed in debugfs in a directory per vcpu that
contains a file called "timings".  This file contains one line for
each of the 5 timings above, with the name followed by a colon and
4 numbers, which are the count (number of times the code has been
executed), the total time, the minimum time, and the maximum time,
all in nanoseconds.

The overhead of the extra code amounts to about 30ns for an hcall that
is handled in real mode (e.g. H_SET_DABR), which is about 25%.  Since
production environments may not wish to incur this overhead, the new
code is conditional on a new config symbol,
CONFIG_KVM_BOOK3S_HV_EXIT_TIMING.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2015-04-21 15:21:31 +02:00

199 lines
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#
# KVM configuration
#
source "virt/kvm/Kconfig"
menuconfig VIRTUALIZATION
bool "Virtualization"
---help---
Say Y here to get to see options for using your Linux host to run
other operating systems inside virtual machines (guests).
This option alone does not add any kernel code.
If you say N, all options in this submenu will be skipped and
disabled.
if VIRTUALIZATION
config KVM
bool
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_EVENTFD
select SRCU
config KVM_BOOK3S_HANDLER
bool
config KVM_BOOK3S_32_HANDLER
bool
select KVM_BOOK3S_HANDLER
select KVM_MMIO
config KVM_BOOK3S_64_HANDLER
bool
select KVM_BOOK3S_HANDLER
config KVM_BOOK3S_PR_POSSIBLE
bool
select KVM_MMIO
select MMU_NOTIFIER
config KVM_BOOK3S_HV_POSSIBLE
bool
config KVM_BOOK3S_32
tristate "KVM support for PowerPC book3s_32 processors"
depends on PPC_BOOK3S_32 && !SMP && !PTE_64BIT
select KVM
select KVM_BOOK3S_32_HANDLER
select KVM_BOOK3S_PR_POSSIBLE
---help---
Support running unmodified book3s_32 guest kernels
in virtual machines on book3s_32 host processors.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
If unsure, say N.
config KVM_BOOK3S_64
tristate "KVM support for PowerPC book3s_64 processors"
depends on PPC_BOOK3S_64
select KVM_BOOK3S_64_HANDLER
select KVM
select KVM_BOOK3S_PR_POSSIBLE if !KVM_BOOK3S_HV_POSSIBLE
---help---
Support running unmodified book3s_64 and book3s_32 guest kernels
in virtual machines on book3s_64 host processors.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
If unsure, say N.
config KVM_BOOK3S_64_HV
tristate "KVM support for POWER7 and PPC970 using hypervisor mode in host"
depends on KVM_BOOK3S_64
select KVM_BOOK3S_HV_POSSIBLE
select MMU_NOTIFIER
select CMA
---help---
Support running unmodified book3s_64 guest kernels in
virtual machines on POWER7 and PPC970 processors that have
hypervisor mode available to the host.
If you say Y here, KVM will use the hardware virtualization
facilities of POWER7 (and later) processors, meaning that
guest operating systems will run at full hardware speed
using supervisor and user modes. However, this also means
that KVM is not usable under PowerVM (pHyp), is only usable
on POWER7 (or later) processors and PPC970-family processors,
and cannot emulate a different processor from the host processor.
If unsure, say N.
config KVM_BOOK3S_64_PR
tristate "KVM support without using hypervisor mode in host"
depends on KVM_BOOK3S_64
select KVM_BOOK3S_PR_POSSIBLE
---help---
Support running guest kernels in virtual machines on processors
without using hypervisor mode in the host, by running the
guest in user mode (problem state) and emulating all
privileged instructions and registers.
This is not as fast as using hypervisor mode, but works on
machines where hypervisor mode is not available or not usable,
and can emulate processors that are different from the host
processor, including emulating 32-bit processors on a 64-bit
host.
config KVM_BOOK3S_HV_EXIT_TIMING
bool "Detailed timing for hypervisor real-mode code"
depends on KVM_BOOK3S_HV_POSSIBLE && DEBUG_FS
---help---
Calculate time taken for each vcpu in the real-mode guest entry,
exit, and interrupt handling code, plus time spent in the guest
and in nap mode due to idle (cede) while other threads are still
in the guest. The total, minimum and maximum times in nanoseconds
together with the number of executions are reported in debugfs in
kvm/vm#/vcpu#/timings. The overhead is of the order of 30 - 40
ns per exit on POWER8.
If unsure, say N.
config KVM_BOOKE_HV
bool
config KVM_EXIT_TIMING
bool "Detailed exit timing"
depends on KVM_E500V2 || KVM_E500MC
---help---
Calculate elapsed time for every exit/enter cycle. A per-vcpu
report is available in debugfs kvm/vm#_vcpu#_timing.
The overhead is relatively small, however it is not recommended for
production environments.
If unsure, say N.
config KVM_E500V2
bool "KVM support for PowerPC E500v2 processors"
depends on E500 && !PPC_E500MC
select KVM
select KVM_MMIO
select MMU_NOTIFIER
---help---
Support running unmodified E500 guest kernels in virtual machines on
E500v2 host processors.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
If unsure, say N.
config KVM_E500MC
bool "KVM support for PowerPC E500MC/E5500/E6500 processors"
depends on PPC_E500MC
select KVM
select KVM_MMIO
select KVM_BOOKE_HV
select MMU_NOTIFIER
---help---
Support running unmodified E500MC/E5500/E6500 guest kernels in
virtual machines on E500MC/E5500/E6500 host processors.
This module provides access to the hardware capabilities through
a character device node named /dev/kvm.
If unsure, say N.
config KVM_MPIC
bool "KVM in-kernel MPIC emulation"
depends on KVM && E500
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQFD
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_MSI
help
Enable support for emulating MPIC devices inside the
host kernel, rather than relying on userspace to emulate.
Currently, support is limited to certain versions of
Freescale's MPIC implementation.
config KVM_XICS
bool "KVM in-kernel XICS emulation"
depends on KVM_BOOK3S_64 && !KVM_MPIC
select HAVE_KVM_IRQCHIP
select HAVE_KVM_IRQFD
default y
---help---
Include support for the XICS (eXternal Interrupt Controller
Specification) interrupt controller architecture used on
IBM POWER (pSeries) servers.
source drivers/vhost/Kconfig
endif # VIRTUALIZATION