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Re: [Qemu-devel] [PATCH v2 0/4] i386/kvm: advertise Hyper-V frequency MS
From: |
Marcelo Tosatti |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/4] i386/kvm: advertise Hyper-V frequency MSRs |
Date: |
Tue, 8 Aug 2017 21:50:53 -0300 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Aug 07, 2017 at 10:56:59AM +0200, Ladi Prosek wrote:
> 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.
>
> v1->v2:
> * deleted an extra empty line in patch 1
> * added patch 3 introducing a helper function for the "TSC is stable and
> known" check (David)
>
> Ladi Prosek (4):
> i386/kvm: use a switch statement for MSR detection
> i386/kvm: set tsc_khz before configuring Hyper-V CPUID
> i386/kvm: introduce tsc_is_stable_and_known()
> i386/kvm: advertise Hyper-V frequency MSRs
>
> target/i386/kvm.c | 138
> ++++++++++++++++++++++++++++--------------------------
> 1 file changed, 71 insertions(+), 67 deletions(-)
>
> --
> 2.9.3
Signed-off-by: Marcelo Tosatti <address@hidden>