I've only been using QEMU a few days now and have to admit the initial learning curve is steeper than Virtualbox or VMWare (not very much so but jumping straight in may leave you wondering where your USB devices and shared drives are). This is not a how-to-tutorial but more of a did-you-know and pointers at what to look for.
- Performance - yes it is noticeably faster as on Linux some of the KVM (kernel-based virtual machine) functionality is included inside the Linux kernel.
- Graphics card passthrough - means the guest OS will access and directly use a Nvidia or AMD graphics card as if it is the native OS on the hardware. This is mind-blowing as it means you could run Windows on Linux, and play all games without Steam for Linux. The only proviso is you must have a second graphics card installed as it cannot actually share a single card in the machine (and there is some config to be done with Grub).
- Flexibility - it's power lies in many ways to achieve the same thing such as sharing USB devices or drives (increases complexity a bit). This increases the learning curve but exponentially increases your options and functionality.
- USB devices - you do want to install Spice tools which are much like Virtualbox's Guest Tools. The easiest way to share a USB device from the host to guest system is, when the guest is running via Virt-Manager, on the window menu go to "Virtual Machine" and select "Redirect USB Device" from the drop down menu and then just tick the devices. Only problem with this method is it seems to limit you to choosing 2 devices at a time (but it's easiest). Mouse and keyboard are already shared.
- Accessing Linux Host drives - I used Samba shares (but there are numerous other ways) and then in Windows guest I mapped to \hostIP\sharename and it worked just fine. The screenshot below shows my two mapped drives (one was an NTFS volume under Linux I use for Steam games) and the hardware info window showing it is QEMU running.
The guest OS I'm using was actually setup under Virtualbox and I converted it to be used under QEMU so it was not even a clean install.
I'll share any interetiing finds again in the future.