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(-) -- 2.7.4
