MFC: r322076

Detect hypervisor early so that we set lower hz on it.
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_M .
M sys/amd64/amd64/machdep.c
M sys/amd64/include/md_var.h
M sys/i386/i386/machdep.c
M sys/i386/include/md_var.h
M sys/x86/x86/identcpu.c

MFC 303753,308004: Add bounds checking on addresses used with /dev/mem.

303753:
Don't permit mappings of invalid physical addresses on amd64 via /dev/mem.

308004:
MFamd64: Add bounds checks on addresses used with /dev/mem.

Reject attempts to read from or memory map offsets in /dev/mem that are
beyond the maximum-supported physical address of the current CPU.

MFC r297857: re-enable AMD Topology extension on certain models if
disabled by BIOS

MFC r286228:
Clear the IA32_MISC_ENABLE MSR bit on APs.

Implement x86 ptrace(2) requests PT_{GET,SET}{FS,GS}BASE.

MFC r284918:
Add helper fill_based_sd(9).

MFC r284919:
Add x86 PT_GETFSBASE, PT_GETGSBASE machine-depended ptrace requests to
obtain the thread %fs and %gs bases. Add x86 PT_SETFSBASE and
PT_SETGSBASE requests to set the bases from debuggers. The set
requests, similarly to the sysarch({I386,AMD64}_SET_FSBASE), override
the corresponding segment registers.

MFC r284965:
Document x86 machine-specific ptrace(2) requests.

MFC r285011:
Disallow a debugger on 64bit system to set fs/gs bases of the 32bit
process beyond the end of the process address space.

MFC r285104:
Grammar and language fixes.

MFC r284104:
Updates from SDM rev. 55.

MFC 273800:
Rework virtual machine hypervisor detection.
- Move the existing code to x86/x86/identcpu.c since it is x86-specific.
- If the CPUID2_HV flag is set, assume a hypervisor is present and query
the 0x40000000 leaf to determine the hypervisor vendor ID. Export the
vendor ID and the highest supported hypervisor CPUID leaf via
hv_vendor[] and hv_high variables, respectively. The hv_vendor[]
array is also exported via the hw.hv_vendor sysctl.
- Merge the VMWare detection code from tsc.c into the new probe in
identcpu.c. Add a VM_GUEST_VMWARE to identify vmware and use that in
the TSC code to identify VMWare.

MFC r277047:
For x86, read MAXPHYADDR into variable cpu_maxphyaddr.

MFC 273988,273989,273995,274057:
MFamd64: Add support for extended FPU states on i386. This includes
support for AVX on i386.

MFC 273991:
MFamd64: Move extern declaration of _ucodesel and _udatasel to
<machine/md_var.h>

MFC 271405,271408,271409,272658:
MFamd64: Use initializecpu() to set various model-specific registers on
AP startup and AP resume (it was already used for BSP startup and BSP
resume).

MFC 260557,271076,271077,271082,271083,271098:
- Remove spaces from boot messages when we print the CPU ID/Family/Stepping
- Move prototypes for various functions into out of C files and into
<machine/md_var.h>.
- Reduce diffs between i386 and amd64 initcpu.c and identcpu.c files.
- Move blacklists of broken TSCs out of the printcpuinfo() function
and into the TSC probe routine.
- Merge the amd64 and i386 identcpu.c into a single x86 implementation.

MFC r286228:
Clear the IA32_MISC_ENABLE MSR bit on APs.

Implement x86 ptrace(2) requests PT_{GET,SET}{FS,GS}BASE.

MFC r284918:
Add helper fill_based_sd(9).

MFC r284919:
Add x86 PT_GETFSBASE, PT_GETGSBASE machine-depended ptrace requests to
obtain the thread %fs and %gs bases. Add x86 PT_SETFSBASE and
PT_SETGSBASE requests to set the bases from debuggers. The set
requests, similarly to the sysarch({I386,AMD64}_SET_FSBASE), override
the corresponding segment registers.

MFC r284965:
Document x86 machine-specific ptrace(2) requests.

MFC r285011:
Disallow a debugger on 64bit system to set fs/gs bases of the 32bit
process beyond the end of the process address space.

MFC r285104:
Grammar and language fixes.

MFC r284104:
Updates from SDM rev. 55.

MFC 273800:
Rework virtual machine hypervisor detection.
- Move the existing code to x86/x86/identcpu.c since it is x86-specific.
- If the CPUID2_HV flag is set, assume a hypervisor is present and query
the 0x40000000 leaf to determine the hypervisor vendor ID. Export the
vendor ID and the highest supported hypervisor CPUID leaf via
hv_vendor[] and hv_high variables, respectively. The hv_vendor[]
array is also exported via the hw.hv_vendor sysctl.
- Merge the VMWare detection code from tsc.c into the new probe in
identcpu.c. Add a VM_GUEST_VMWARE to identify vmware and use that in
the TSC code to identify VMWare.

MFC r277047:
For x86, read MAXPHYADDR into variable cpu_maxphyaddr.

MFC 273988,273989,273995,274057:
MFamd64: Add support for extended FPU states on i386. This includes
support for AVX on i386.

MFC 273991:
MFamd64: Move extern declaration of _ucodesel and _udatasel to
<machine/md_var.h>

MFC 271405,271408,271409,272658:
MFamd64: Use initializecpu() to set various model-specific registers on
AP startup and AP resume (it was already used for BSP startup and BSP
resume).

MFC 260557,271076,271077,271082,271083,271098:
- Remove spaces from boot messages when we print the CPU ID/Family/Stepping
- Move prototypes for various functions into out of C files and into
<machine/md_var.h>.
- Reduce diffs between i386 and amd64 initcpu.c and identcpu.c files.
- Move blacklists of broken TSCs out of the printcpuinfo() function
and into the TSC probe routine.
- Merge the amd64 and i386 identcpu.c into a single x86 implementation.