crosvm

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History

Noah Gold 4ea25d1e33 x86_64: add TSC leaf synthesis. 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>	2022-06-28 02:23:55 +00:00
..
src	x86_64: add TSC leaf synthesis.	2022-06-28 02:23:55 +00:00
Cargo.toml

Noah Gold 4ea25d1e33 x86_64: add TSC leaf synthesis.

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>

2022-06-28 02:23:55 +00:00

src x86_64: add TSC leaf synthesis. 2022-06-28 02:23:55 +00:00

Cargo.toml