[PATCH 0/4] Allow migration with invtsc if there's no frequency mismatch

Eduardo Habkost
2016-12-27T19:21:16Z

This series makes QEMU accept migration with invtsc if:

a) The destination host has a matching TSC frequency; or
b) The destination host has TSC scaling available.

There are two cases where we can ensure the above conditions.
This series implements both:

1) tsc-khz explicitly set on the configuration. This case is
trivial because the current code already refuses to start if
there's a TSC frequency mismatch and tsc-khz is explicitly
configured. (Implemented by patch 2/4)

2) A newer machine-type is being used. This means we know that
the migration destination is running a QEMU version that will
check for (a) and (b) on migration even if tsc-khz is not set
explicitly. (Implemented by patch 4/4)

Eduardo Habkost (4):
kvm: Simplify invtsc check
kvm: Allow invtsc migration if tsc-khz is set explicitly
pc: Add 2.9 machine-types
kvm: Allow migration with invtsc

include/hw/i386/pc.h | 6 ++++++
target/i386/cpu.h | 1 +
hw/i386/pc_piix.c | 15 ++++++++++++---
hw/i386/pc_q35.c | 13 +++++++++++--
target/i386/cpu.c | 1 +
target/i386/kvm.c | 32 ++++++++++++++++++--------------
6 files changed, 49 insertions(+), 19 deletions(-)

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2.7.4