On a nested page table fault the hypervisor will:
- fetch the instruction using the guest %rip and %cr3
- decode the instruction in 'struct vie'
- emulate the instruction in host kernel context for local apic accesses
- any other type of mmio access is punted up to user-space (e.g. ioapic)
The decoded instruction is passed as collateral to the user-space process
that is handling the PAGING exit.
The emulation code is fleshed out to include more addressing modes (e.g. SIB)
and more types of operands (e.g. imm8). The source code is unified into a
single file (vmm_instruction_emul.c) that is compiled into vmm.ko as well
as /usr/sbin/bhyve.
Reviewed by: grehan
Obtained from: NetApp
- New memory region interface. An RB tree holds the regions,
with a last-found per-vCPU cache to deal with the common case
of repeated guest accesses to MMIO registers in the same page.
- Support memory-mapped BARs in PCI emulation.
mem.c/h - memory region interface
instruction_emul.c/h - remove old region interface.
Use gpa from EPT exit to avoid a tablewalk to
determine operand address. Determine operand size
and use when calling through to region handler.
fbsdrun.c - call into region interface on paging
exit. Distinguish between instruction emul error
and region not found
pci_emul.c/h - implement new BAR callback api.
Split BAR alloc routine into routines that
require/don't require the BAR phys address.
ioapic.c
pci_passthru.c
pci_virtio_block.c
pci_virtio_net.c
pci_uart.c - update to new BAR callback i/f
Reviewed by: neel
Obtained from: NetApp
