From: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
KVM will use it to switch pkru between guest and host.
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 6 ++++++
arch/x86/include/asm/special_insns.h | 16 ++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1ff49ec..97f3242 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -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;
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index aee6e76..d96d043 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -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)
--
1.8.3.1
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