This is the QEMU part of the changes required for nested Hyper-V to read timestamps with RDTSC + TSC page. Without exposing the frequency MSRs, Windows with the Hyper-V role enabled use the much slower HV_X64_MSR_TIME_REF_COUNT (0x40000020) RDMSR to read timestamps.
The new registers are exposed only if the TSC frequency is stable across migration and known, as suggested by Paolo. Ladi Prosek (3): i386/kvm: use a switch statement for MSR detection i386/kvm: set tsc_khz before configuring Hyper-V CPUID i386/kvm: advertise Hyper-V frequency MSRs target/i386/kvm.c | 130 +++++++++++++++++++++++++++--------------------------- 1 file changed, 66 insertions(+), 64 deletions(-) -- 2.9.3
