From 9e90199c25aec31b4509213881511948f6c763c8 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Tue, 22 Mar 2016 16:51:17 +0800 Subject: [PATCH] x86: pkey: introduce write_pkru() for KVM KVM will use it to switch pkru between guest and host. CC: Ingo Molnar CC: Dave Hansen Signed-off-by: Xiao Guangrong Signed-off-by: Huaitong Han Signed-off-by: Paolo Bonzini --- 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 1ff49ec29ece..97f3242e133c 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 aee6e76e561e..d96d04377765 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) -- 2.20.1