fd4f6b8020
When I implemented TSC scaling originally, I chose a scale factor of 128 because it basically covered the range of devices we cared about without going too high. I also only tested devices that had a TSC scale factor from 19.2Mhz to 34Mhz. Turns out there is hardware that also has a 48Mhz cycle counter, which cause them to effectively have a 6.1Ghz cycle counter, which is kind of absurd. Instead of a fixed scale, just calculate the amount of scaling we need to get >= the minimum threshold of 1Ghz. This will change the shift from 7 to 5 or 6 for the faster cycle counter devices. Of course if someone wants to know the scale factor they can still use cpuid function 15h to know it. Fixes #4026
FEX - Fast x86 emulation frontend
FEX allows you to run x86 and x86-64 binaries on an AArch64 host, similar to qemu-user and box86. It has native support for a rootfs overlay, so you don't need to chroot, as well as some thunklibs so it can forward things like GL to the host. FEX presents a Linux 5.0+ interface to the guest, and supports only AArch64 as a host. FEX is very much work in progress, so expect things to change.
Quick start guide
For Ubuntu 20.04, 21.04, 21.10, 22.04
Execute the following command in the terminal to install FEX through a PPA.
curl --silent https://raw.githubusercontent.com/FEX-Emu/FEX/main/Scripts/InstallFEX.py --output /tmp/InstallFEX.py && python3 /tmp/InstallFEX.py && rm /tmp/InstallFEX.py
This command will walk you through installing FEX through a PPA, and downloading a RootFS for use with FEX.
Ubuntu PPA is updated with our monthly releases.
For everyone else
Please see Building FEX.
Getting Started
FEX has been tested to build and run on ARMv8.0+ hardware. ARMv7 hardware will not work. Expected operating system usage is Linux. FEX has been tested with Ubuntu 20.04, 20.10, and 21.04. Also Arch Linux.
On AArch64 hosts the user MUST have an x86-64 RootFS Creating a RootFS.
Navigating the Source
See the Source Outline for more information.
Building FEX
Follow the guide on the official FEX-Emu Wiki here.
RootFS generation
AArch64 hosts require a rootfs for running applications. Follow the guide on the wiki page for seeing how to set up the rootfs from scratch https://wiki.fex-emu.com/index.php/Development:Setting_up_RootFS
