[PATCH 12/27] x86/pkru: Provide .*_pkru_ins() functions

Sebastian Andrzej Siewior
2019-04-03T16:44:23Z

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 <dave.hansen@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
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(-)

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 ab432a930ae86..96dec81430970 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6501,7 +6501,7 @@ 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);
}
--
2.20.1