tree ee030d59b2e665bbfb991c656fb13e7d2fd91f8f
parent fec27f4d23b7335a72c4c6a4bb75e94e7500669a
author Liam Merwick <liam.merwick@oracle.com> 1542910057 +0000
committer Paolo Bonzini <bonzini@gnu.org> 1546003889 +0100

pvh: add benchmark exit point

This commit adds a PVH specific VM exit point for use in benchmarking
boot times using a QEMU specific device that terminates the QEMU process
and thus the VM itself when handling those VM exits. Since the VM
terminates right at those exit points, generic tools like time can
be used to measure the time spent between the QEMU startup
and termination moments.

The QEMU device used for those measurement is called isa-debug-exit
for the PC and Q35 machine types. These devices take 2 arguments:
iobase and iosize.  iobase specifies which IO port we need to write
into to have these devices eventually handle the corresponding VM exit.

If for example, QEMU is started with the following argument:

-device isa-debug-exit,iobase=0xf4

then any IO write to 0xf4 will terminate the QEMU process and the
corresponding VM.

Signed-off-by: Liam Merwick <liam.merwick@oracle.com>