d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Preserve other bits in IA32_SPEC_CTL MSR when changing the IBRS and

Browse Source 
STIBP states.

Tested by:	emaste (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
This commit is contained in:
kib 2018-05-21 21:05:55 +00:00
parent 94ea6109fb
commit 5574ca2f4a
1 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
sys/amd64/amd64/support.S
View File

@ -958,8 +958,9 @@ ENTRY(handle_ibrs_entry)
cmpb $0,hw_ibrs_active(%rip)
je 1f
movl $MSR_IA32_SPEC_CTRL,%ecx
movl $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
movl $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32,%edx
rdmsr
orl $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
orl $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32,%edx
wrmsr
movb $1,PCPU(IBPB_SET)
testl $CPUID_STDEXT_SMEP,cpu_stdext_feature(%rip)
@ -972,8 +973,9 @@ ENTRY(handle_ibrs_exit)
cmpb $0,PCPU(IBPB_SET)
je 1f
movl $MSR_IA32_SPEC_CTRL,%ecx
xorl %eax,%eax
xorl %edx,%edx
rdmsr
andl $~(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
andl $~((IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32),%edx
wrmsr
movb $0,PCPU(IBPB_SET)
1: ret
@ -987,8 +989,9 @@ ENTRY(handle_ibrs_exit_rs)
pushq %rdx
pushq %rcx
movl $MSR_IA32_SPEC_CTRL,%ecx
xorl %eax,%eax
xorl %edx,%edx
rdmsr
andl $~(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
andl $~((IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32),%edx
wrmsr
popq %rcx
popq %rdx