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x86: pkey: introduce write_pkru() for KVM 

KVM will use it to switch pkru between guest and host.

CC: Ingo Molnar <mingo@redhat.com>
CC: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiao Guangrong 2016-03-22 16:51:17 +08:00 committed by Paolo Bonzini
parent 17a511f878
commit 9e90199c25
2 changed files with 22 additions and 0 deletions
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6
arch/x86/include/asm/pgtable.h
View File

@ -107,6 +107,12 @@ static inline u32 read_pkru(void)
return 0;
}
static inline void write_pkru(u32 pkru)
{
if (boot_cpu_has(X86_FEATURE_OSPKE))
__write_pkru(pkru);
}
static inline int pte_young(pte_t pte)
{
return pte_flags(pte) & _PAGE_ACCESSED;

16
arch/x86/include/asm/special_insns.h
View File

@ -113,11 +113,27 @@ static inline u32 __read_pkru(void)
: "c" (ecx));
return pkru;
}
static inline void __write_pkru(u32 pkru)
{
u32 ecx = 0, edx = 0;
/*
* "wrpkru" instruction. Loads contents in EAX to PKRU,
* requires that ecx = edx = 0.
*/
asm volatile(".byte 0x0f,0x01,0xef\n\t"
: : "a" (pkru), "c"(ecx), "d"(edx));
}
#else
static inline u32 __read_pkru(void)
{
return 0;
}
static inline void __write_pkru(u32 pkru)
{
}
#endif
static inline void native_wbinvd(void)