There have been two evolutions of providing the TSC cpuid leaf
(aka 0x15) to the guest.
a) For CrosVM on Windows, we have been providing the leaf
unconditionally. Furthermore, we've not been using the
exact host leaf; instead, we calibrate the TSC frequency
and provide that value in the leaf. This was done because
the actual cpuid leaf values are not as accurate as
we needed them to be to drive a guest clocksource.
b) In CrosVM mainline, 4080aaf9b3
introduced the flag enable_pnp / enable_pnp_data, and
provides the exact host 0x15 leaf to the guest if the
flag is enabled.
This CL adds a new hypervisor capability (CalibratedTscLeafRequired) to control
whether or not the calibrated TSC leaf should be used, in addition to a new CLI
option to force it on hypervisors where it isn't enabled by default. The new
option is `--force_calibrated_tsc_leaf`.
BUG=b:213152505
TEST=builds upstream, battletested downstream on WHPX.
Change-Id: I611422808a9e10578c0ddcbd211ae902f937685f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3698993
Commit-Queue: Noah Gold <nkgold@google.com>
Reviewed-by: Junichi Uekawa <uekawa@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
crosvm is a virtual machine monitor (VMM) based on Linux’s KVM hypervisor, with a focus on
simplicity, security, and speed. crosvm is intended to run Linux guests, originally as a security
boundary for running native applications on the Chrome OS platform. Compared to QEMU, crosvm doesn’t
emulate architectures or real hardware, instead concentrating on paravirtualized devices, such as
the virtio standard.
crosvm is currently used to run Linux/Android guests on Chrome OS devices.
For contribution, see the contributor guide.
Mirror repository is available at GitHub for your
convenience, but we don't accept bug reports or pull requests there.
4ea25d1e33
