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| -rw-r--r-- | README.md | 2 | ||||
| -rw-r--r-- | writeups/hackintosh/usbredir.md | 70 |
2 files changed, 64 insertions, 8 deletions
@@ -43,6 +43,8 @@ I hope you enjoy your stay! Console - [powershell-email/README.md](writeups/powershell-email/README.md): send emails in Powershell + - [hackintosh/cloud+libvirt.md](writeups/hackintosh/cloud+libvirt.md): + hackintosh on cloud ## Copyright Unless classified otherwise, all the work I do I go by Apache-2.0. Mate, if I diff --git a/writeups/hackintosh/usbredir.md b/writeups/hackintosh/usbredir.md index 7b1c744..0ca19a7 100644 --- a/writeups/hackintosh/usbredir.md +++ b/writeups/hackintosh/usbredir.md @@ -1,9 +1,10 @@ -That 10 ms delay is apparently detrimental. It makes sense because USB is meant -to be work over short distances. The protocol and even the electrical -characteristics are built upon this assumption. USB frames are short in length -and polled frequently, and almost no buffering is done in the background as it -works closely on the hardware. Therefore, performance hit is inevitable and -instability issues are expected when USB frames are passed over IP. +That 10+ ms delay is apparently detrimental. It makes sense because USB is +designed to work over short distances. The protocol and (even) electrical +characteristics are built upon this assumption. The USB frames are short in +length and polled frequently, and almost no buffering is done in the background +as it works closely on the hardware. Therefore, the performance hit is +inevitable and instability issues are expected when USB frames are passed over +IP. The usb-redir devices are attached via qemu command line passthrough. virt-manager is not "aware" of this and it doesn't even try to see if there usb @@ -22,5 +23,58 @@ Some usb devices don't like getting passed around over the network. | Flash Drives | ✅YES | 🫳kinda(slow) | | HID(keyboard and mouse) | ✅YES | ✅YES | -### Analysis: Android and IOS Devices -TODO +### TODO Analysis: Android and IOS Devices +This is work in progress. + +Points: + +- To make XNU kernel happy, the devices must be attached to a hub. The kernel + cannot enumerate usb devices directly hot-plugged in the controller + - Performance hit due to the fact that qemu only supports emulation of + full-speed usb hub +- Massive round-trip delay over the network in terms of USB(which speaks in + nanosecond terms) + - As a result, it's possible that Android and IOS devices initiate USB reset + rather than patiently sticking up with the delay (possibly)due to the + limitation of hardware/firmware(TODO: inspect Logcat and Xcode instruments + to verify it) +- TODO: Instead of using USB redirection, USB devices can be attached to the + controller on guest start up +- There are many components that make the USB redirection over network possible. + Quite possibly, the culprit could be one of the components along the chain +- The issue is present on other proprietary solutions using VHCI as + well(FlexiHub, VirtualHere) + - meaning that it's likely the "massive round-trip delay" issue + - or it's a bug in the encapsulation protocol/implementation that's common in + all proprietary/FOSS implementation + +"The chain": + +``` + <- NET -> +CLIENT HOST +tcp/ip tcp/ip +ssh ssh +spice+usbredir libvirt +libusb spice +virt-viewer qemu + xhci + usb-hub + usb-redir +``` + +"The components" + +- virt + - ssh tunneling + - USB/IP + - SPICE + - libusb + - usbredir + - usb/ip +- QEMU + - xhci + - usb-hub + - usb-redir +- Apple + - Apple VHCI |