MFC r273683

MFC r273683
Move the ACPI PM timer emulation into vmm.ko.

MFC r273706
Change the type of the first argument to the I/O emulation handlers to
'struct vm *'.

MFC r273710
Add a comment explaining the intent behind the I/O reservation [0x72-0x77].

MFC r273744
Add foo_genassym.c files to DPSRCS so dependencies for them are generated.
This ensures these objects are rebuilt to generate an updated header of
assembly constants if needed.

MFC r274045
If the start bit, PxCMD.ST, is cleared and nothing is in-flight then
PxCI, PxSACT, PxCMD.CCS and PxCMD.CR should be 0.

MFC r274076
Improve the ability to cancel an in-flight request by using an interrupt,
via SIGCONT, to force the read or write system call to return prematurely.

MFC r274330
To allow a request to be submitted from within the callback routine of
a completing one increase the total by 1 but don't advertise it.

MFC r274931
Change the lower bound for guest vmspace allocation to 0 instead of using
the VM_MIN_ADDRESS constant.

MFC r275817
For level triggered interrupts clear the PIC IRR bit when the interrupt pin
is deasserted.

MFC r275850
Fix 8259 IRQ priority resolver.

MFC r275952
Various 8259 device model improvements.

MFC r275965
Emulate writes to the IA32_MISC_ENABLE MSR.

git-svn-id: svn://svn.freebsd.org/base/stable/10@276429 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f