[12/24] x86/pkru: Provide .*_pkru_ins() functions

Commit Message

Sebastian Andrzej Siewior March 21, 2019, 8:26 p.m. UTC

Dave Hansen has asked for __read_pkru() and __write_pkru() to be symmetrical.
As part of the series __write_pkru() will read back the value and only write it
if it is different.
In order to make both functions symmetrical move the function containing only
the opcode into a function with _isn() suffix. __write_pkru() will just invoke
__write_pkru_isn() but in a flowup patch will also read back the value.

Suggested-by: Dave Hansen <[e-mail]>
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
---
 arch/x86/include/asm/pgtable.h       |  2 +-
 arch/x86/include/asm/special_insns.h | 12 +++++++++---
 arch/x86/kvm/vmx/vmx.c               |  2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

Patch

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23f..64333e5222cd9 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -127,7 +127,7 @@  static inline int pte_dirty(pte_t pte)
 static inline u32 read_pkru(void)
 {
 	if (boot_cpu_has(X86_FEATURE_OSPKE))
-		return __read_pkru();
+		return __read_pkru_ins();
 	return 0;
 }
 
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index 43c029cdc3fe8..27328606ff687 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -92,7 +92,7 @@  static inline void native_write_cr8(unsigned long val)
 #endif
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-static inline u32 __read_pkru(void)
+static inline u32 __read_pkru_ins(void)
 {
 	u32 ecx = 0;
 	u32 edx, pkru;
@@ -107,7 +107,7 @@  static inline u32 __read_pkru(void)
 	return pkru;
 }
 
-static inline void __write_pkru(u32 pkru)
+static inline void __write_pkru_ins(u32 pkru)
 {
 	u32 ecx = 0, edx = 0;
 
@@ -118,8 +118,14 @@  static inline void __write_pkru(u32 pkru)
 	asm volatile(".byte 0x0f,0x01,0xef\n\t"
 		     : : "a" (pkru), "c"(ecx), "d"(edx));
 }
+
+static inline void __write_pkru(u32 pkru)
+{
+	__write_pkru_ins(pkru);
+}
+
 #else
-static inline u32 __read_pkru(void)
+static inline u32 __read_pkru_ins(void)
 {
 	return 0;
 }
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c73375e01ab8c..0753b3967423a 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6514,7 +6514,7 @@  static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	 */
 	if (static_cpu_has(X86_FEATURE_PKU) &&
 	    kvm_read_cr4_bits(vcpu, X86_CR4_PKE)) {
-		vcpu->arch.pkru = __read_pkru();
+		vcpu->arch.pkru = __read_pkru_ins();
 		if (vcpu->arch.pkru != vmx->host_pkru)
 			__write_pkru(vmx->host_pkru);
 	}