MFC r320755,r320762,r320893:
BIT_FLS(9).

MFC r318781:
Add BIT_OR2(), BIT_AND2(), BIT_NAND2(), BIT_XOR() and BIT_XOR2().

MFC 278474,278476,280279:
Expand the bitcount*() API and use it to implement CPU_COUNT for cpusets.

278474:
Use __builtin_popcnt() to implement a BIT_COUNT() operation for bitsets and
use this to implement CPU_COUNT() to count the number of CPUs in a cpuset.

278476:
Use __builtin_popcountl() instead of __builtin_popcount().

280279:
Expand the bitcount* API to support 64-bit integers, plain ints and longs
and create a "hidden" API that can be used in other system headers without
adding namespace pollution.
- If the POPCNT instruction is enabled at compile time, use
__builtin_popcount*() to implement __bitcount*(), otherwise fall back
to software implementations.
- Use the existing bitcount16() and bitcount32() from <sys/systm.h> to
implement the non-POPCNT __bitcount16() and __bitcount32() in
<sys/types.h>.
- For the non-POPCNT __bitcount64(), use a similar SWAR method on 64-bit
systems. For 32-bit systems, use two __bitcount32() operations on the
two halves.
- Use __bitcount32() to provide a __bitcount() that operates on plain ints.
- Use either __bitcount32() or __bitcount64() to provide a
__bitcountl() that operates on longs.
- Add public bitcount*() wrappers for __bitcount*() for use in the kernel
in <sys/libkern.h>.
- Use __bitcountl() instead of __builtin_popcountl() in BIT_COUNT().

MFC 261321
Rename the AMD MSR_PERFCTR[0-3] so the Pentium Pro MSR_PERFCTR[0-1] aren't
redefined.

MFC r273214
Fix build to not bogusly always rebuild vmm.ko.

MFC r273338
Add support for AMD's nested page tables in pmap.c:
- Provide the correct bit mask for various bit fields in a PTE (e.g. valid bit)
for a pmap of type PT_RVI.
- Add a function 'pmap_type_guest(pmap)' that returns TRUE if the pmap is of
type PT_EPT or PT_RVI.

Add CPU_SET_ATOMIC_ACQ(num, cpuset):
This is used when activating a vcpu in the nested pmap. Using the 'acquire'
variant guarantees that the load of the 'pm_eptgen' will happen only after
the vcpu is activated in 'pm_active'.

Add defines for various AMD-specific MSRs.

Discussed with: kib (r261321)

MFC 278474,278476,280279:
Expand the bitcount*() API and use it to implement CPU_COUNT for cpusets.

278474:
Use __builtin_popcnt() to implement a BIT_COUNT() operation for bitsets and
use this to implement CPU_COUNT() to count the number of CPUs in a cpuset.

278476:
Use __builtin_popcountl() instead of __builtin_popcount().

280279:
Expand the bitcount* API to support 64-bit integers, plain ints and longs
and create a "hidden" API that can be used in other system headers without
adding namespace pollution.
- If the POPCNT instruction is enabled at compile time, use
__builtin_popcount*() to implement __bitcount*(), otherwise fall back
to software implementations.
- Use the existing bitcount16() and bitcount32() from <sys/systm.h> to
implement the non-POPCNT __bitcount16() and __bitcount32() in
<sys/types.h>.
- For the non-POPCNT __bitcount64(), use a similar SWAR method on 64-bit
systems. For 32-bit systems, use two __bitcount32() operations on the
two halves.
- Use __bitcount32() to provide a __bitcount() that operates on plain ints.
- Use either __bitcount32() or __bitcount64() to provide a
__bitcountl() that operates on longs.
- Add public bitcount*() wrappers for __bitcount*() for use in the kernel
in <sys/libkern.h>.
- Use __bitcountl() instead of __builtin_popcountl() in BIT_COUNT().

MFC 261321
Rename the AMD MSR_PERFCTR[0-3] so the Pentium Pro MSR_PERFCTR[0-1] aren't
redefined.

MFC r273214
Fix build to not bogusly always rebuild vmm.ko.

MFC r273338
Add support for AMD's nested page tables in pmap.c:
- Provide the correct bit mask for various bit fields in a PTE (e.g. valid bit)
for a pmap of type PT_RVI.
- Add a function 'pmap_type_guest(pmap)' that returns TRUE if the pmap is of
type PT_EPT or PT_RVI.

Add CPU_SET_ATOMIC_ACQ(num, cpuset):
This is used when activating a vcpu in the nested pmap. Using the 'acquire'
variant guarantees that the load of the 'pm_eptgen' will happen only after
the vcpu is activated in 'pm_active'.

Add defines for various AMD-specific MSRs.

Discussed with: kib (r261321)