On Thu, Jun 20, 2024 at 11:16:14PM -0700, Dexuan Cui wrote:
In a TDX VM without paravisor, currently the default timer is the Hyper-V timer, which depends on the slow VM Reference Counter MSR: the Hyper-V TSC page is not enabled in such a VM because the VM uses Invariant TSC as a better clocksource and it's challenging to mark the Hyper-V TSC page shared in very early boot.
Lower the rating of the Hyper-V timer so the local APIC timer becomes the the default timer in such a VM, and print a warning in case Invariant TSC is unavailable in such a VM. This change should cause no perceivable performance difference.
Cc: stable@vger.kernel.org # 6.6+ Reviewed-by: Roman Kisel romank@linux.microsoft.com Signed-off-by: Dexuan Cui decui@microsoft.com
Applied to hyperv-fixes. Thanks.