You cant, its impossible really, you could remote through via RealVNC but that requires two machines. Would it even be possible theoretically, I don't think so. The closest you will get to is PCI passthrough but this comes with a lot of issues, 1st is that shutting down the VM cause cause the X server to outright crash, requiring a full system reboot (Which defeats the point in VMs) I believe this is due to binding issues. Second is hardware, not all hardware can do this, effectively making a PCI device plug+play was never the idea, maybe in the future. Third is drives, virtual drives are slow as hell so a physical drive is required, which again defeats the point of virtualizing the drive.
Its something that is classed as experimental and best viewed as that for the most part, I fully endorse it but seriously best thing you can do at the moment is dual boot. Unless someone has made a script that can auto unbind when VM is turned on and when the guest is told to halt it rebinds all devices which I don't think has :(
Oh and another thing you need to look at is the bootloaders and initials, Linux init will work different from Windows initializer, and the bootloader will have different payloads also, grub can offset this to a point but its still a mess when something is updated, so fragile.
While I've heard of people having this issue, I do not, but then the GPU, NIC and USB controler I'm passing through Linux never see's as it is essentially black listed in grub before Linux has a chance to bind the devices, but yeah virtualized devices passed through that the host must unbind and rebind is a problem which is why I gave my KVM a entire hard drive that is totally separate from the host system.
But I do have issues, the biggest being slower than normal disk access while running Photoshop and I believe it is tied to the scratch disk but it's not been a headache for me although it does exist, the second issue I have is sound latency in the guest because of the host and guest sharing a sound card, it's a easy issue to fix by adding a USB sound device and passing it directly to the guest, just haven't gotten around to doing it. (maybe this fall when I have more time), those two are my biggest concerns and as you can see it's not a big deal...at least in my mind.
I'm probably different than most in that when I boot my machine after Linux is up and I'm logged in I start the KVM and boot Windows also, both are always running when my computer is booted up and they both stay that way until I either shut down, need to reboot, or windows crashes...funny thing Windows can crash but it never effects the host, it has a few times crashed the VM manager and required it to be restarted then the guest restarted neither requiring a reboot of the host....so if my system is running then Windows is also running in a KVM I don't start and stop windows it runs until I need to reboot the entire system and as I said above as soon as Linux is up then Windows gets brought back up also, and I do reboot windows from time to time it is necessary after installing something in a lot of cases to reboot Windows because it's one of Windows favorite things to do....reboot! lol
See I am at the other end of problems, While I can get almost perfect drive performance by just commiting the drive outright, I have a lot of GPU problems when binding, mostly the host saying it cannot be done, I am thinking of getting another GPU installed to deal with it as the iGPU does not seem to do it correctly for me and I am still unsure if the iGPU in a 2nd gen Intel needs patching. The other issue I have is permissions, I get a lot of permission errors when building the VM, even when I allow KVM/Xen into root I still get them, a bit annoying and requires work that shouldn't be needed, shame its not just an SELinux policy but this also happens on Debian based systems and other distros :(.
There was a guy some years ago by the name of Darren Cepulis who invented a bios that would during the pre-boot phase seperate hardware resources to run multiple operating systems simultaneously and independently.
Pretty sure ARM Holdings employed him, and took his invention.