static bool handle_ept_fault(struct guest_thread *gth)
{
struct vm_trapframe *vm_tf = gth_to_vmtf(gth);
struct virtual_machine *vm = gth_to_vm(gth);
uint64_t gpa, *regp;
uint8_t regx;
int store, size;
int advance;
if (decode(gth, &gpa, ®x, ®p, &store, &size, &advance))
return FALSE;
assert(size >= 0);
/* TODO use helpers for some of these addr checks. the fee/fec ones might
* be wrong too. */
for (int i = 0; i < VIRTIO_MMIO_MAX_NUM_DEV; i++) {
if (vm->virtio_mmio_devices[i] == NULL)
continue;
if (PG_ADDR(gpa) != vm->virtio_mmio_devices[i]->addr)
continue;
/* TODO: can the guest cause us to spawn off infinite threads? */
if (store)
virtio_mmio_wr(vm, vm->virtio_mmio_devices[i], gpa, size,
(uint32_t *)regp);
else
*regp = virtio_mmio_rd(vm, vm->virtio_mmio_devices[i], gpa, size);
vm_tf->tf_rip += advance;
return TRUE;
}
if (PG_ADDR(gpa) == 0xfec00000) {
do_ioapic(gth, gpa, regx, regp, store);
} else if (PG_ADDR(gpa) == 0) {
memmove(regp, &vm->low4k[gpa], size);
} else {
fprintf(stderr, "EPT violation: can't handle %p\n", gpa);
fprintf(stderr, "RIP %p, exit reason 0x%x\n", vm_tf->tf_rip,
vm_tf->tf_exit_reason);
fprintf(stderr, "Returning 0xffffffff\n");
showstatus(stderr, gth);
/* Just fill the whole register for now. */
*regp = (uint64_t) -1;
return FALSE;
}
vm_tf->tf_rip += advance;
return TRUE;
}
/* Convert a kernel guest virtual address to physical address.
* Assumes that the guest VA is in the high negative address space.
* TODO: Takes the vm_thread argument so that we can walk the page tables
* instead of just coercing the pointer. Therefore, this is not in vmm.h
* since it may get complex. */
int gvatogpa(struct guest_thread *vm_thread, uint64_t va, uint64_t *pa)
{
assert(vm_thread != NULL);
struct vm_trapframe *vm_tf = gth_to_vmtf(vm_thread);
uint64_t *ptptr = (uint64_t *)vm_tf->tf_cr3;
uint64_t entry;
for (int shift = PML4_SHIFT; shift >= PML1_SHIFT; shift -= BITS_PER_PML) {
entry = ptptr[PMLx(va, shift)];
if (!PAGE_PRESENT(entry))
return -1;
if ((entry & PTE_PS) != 0) {
uint64_t bitmask = ((1 << shift) - 1);
*pa = (((uint64_t)va & bitmask) | (entry & ~bitmask));
return 0;
}
ptptr = (uint64_t *)PG_ADDR(entry);
}
*pa = ((uint64_t)va & 0xfff) | (uint64_t)ptptr;
return 0;
}