TODO

The following items need some love. Please post to the list if you are interested in helping out:

Real mode support: VT support for real mode is terrible, so we need to do it in software. This means extending the x86 emulator (x86_emulate.c) to handle more instructions, and changing the execution loop to call the emulator for real mode (in progress).
Move the apic/ioapic/pic/pit emulation into the kernel. This will simplify in-kernel paravirtualized devices (as there is no need to exit to userspace to inject an interrupt) and guest SMP (in progress).
Drop the preemption counter while doing mmu stuff, and turn kvm->lock into a mutex.
- Even better, hook the state switch to the scheduler, and do away with disabling preemption completely (in progress).
Emulate the architectural performance monitor counters/msrs, for Linux nmi watchdog support.

The following smaller scale tasks can be a nice entry point to someone wishing to get involved:

Enforce the virtual time stamp counter monotonicity even when a vcpu is migrated to another physical cpu. (done for AMD, in progress for Intel)
Trap #UD and emulate sysenter/syscall/sysret/sysexit. These instructions don't exist on all cpus in all modes, so they hinder cross-vendor migration
Consolidate the various functions that read and write guest memory. There is some duplication there.
Consolidate the inb/outb emulation helpers into x86_emulate.c
struct kvm_vcpu has many vmx specific fields. Move them into a new member vmx. Have each arch allocate the vcpu so its arch-specific members can be addressed without indirection (PaulTurner has started this).

MMU related:

Attach kvm memory to a Linux address_space so that guest memory can be paged out (patch exists for alternative approach to guest paging).
Support large pages (in conjunction with the item above) so that if the guest uses a large page mapping and the guest memory is backed by hugetlbfs, a large-page pte is created.
Improve mmu page eviction algorithm (currently FIFO, change to approximate LRU).
Add a read-only memory type.
Implement AM20 for dos and the like.
Implement direct page tables on paravirt_ops enabled Linux guests (in progress)

For the adventurous:

Emulate the VT and SVM instructions, so that kvm can run in a virtual machine. Test by running a VM in a VT guest in an SVM guest on VT hardware, as well as running a VM in an SVM guest in a VT guest on SVM hardware.
Emulate the VT and SVM instruction sets on qemu. This would be very beneficial to debugging kvm.
Keep this TODO up to date