Files
acrn-hypervisor/hypervisor
Shiqing Gao 0abb809ed1 hv: initialize and save/restore IA32_TSC_AUX MSR for guest
Commit cbf3825 "hv: Pass-through IA32_TSC_AUX MSR to L1 guest"
lets guest own the physical MSR IA32_TSC_AUX and does not handle this MSR
in the hypervisor.
If multiple vCPUs share the same pCPU, when one vCPU reads MSR IA32_TSC_AUX,
it may get the value set by other vCPUs.

To fix this issue, this patch does:
 - initialize the MSR content to 0 for the given vCPU, which is consistent with
   the value specified in SDM Vol3 "Table 9-1. IA-32 and Intel 64 Processor
   States Following Power-up, Reset, or INIT"
 - save/restore the MSR content for the given vCPU during context switch

v1 -> v2:
 * According to Table 9-1, the content of IA32_TSC_AUX MSR is unchanged
   following INIT, v2 updates the initialization logic so that the content for
   vCPU is consistent with SDM.

Tracked-On: #6799
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
2021-11-11 13:20:37 +08:00
..
2021-10-14 15:04:36 +08:00
2021-11-10 14:37:47 +08:00

ACRN Hypervisor
###############

The open source `Project ACRN`_ defines a device hypervisor reference stack and
an architecture for running multiple software subsystems, managed securely, on
a consolidated system by means of a virtual machine manager. It also defines a
reference framework implementation for virtual device emulation, called the
"ACRN Device Model".

The ACRN Hypervisor is a Type 1 reference hypervisor stack, running directly on
the bare-metal hardware, and is suitable for a variety of IoT and embedded
device solutions. The ACRN hypervisor addresses the gap that currently exists
between datacenter hypervisors, and hard partitioning hypervisors. The ACRN
hypervisor architecture partitions the system into different functional
domains, with carefully selected guest OS sharing optimizations for IoT and
embedded devices.

You can find out more about Project ACRN on the `Project ACRN documentation`_
website.

.. _`Project ACRN`: https://projectacrn.org
.. _`ACRN Hypervisor`: https://github.com/projectacrn/acrn-hypervisor
.. _`Project ACRN documentation`: https://projectacrn.github.io/