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

Borislav Petkov
2019-04-10T16:52:50Z

On Wed, Apr 10, 2019 at 06:36:15PM +0200, Borislav Petkov wrote:
> Well, this is going in the wrong direction. The proper thing to do would
> be to have:
>
> rdpkru()
> wrpkru()
>
> which only do the inline asm with the respective opcodes. Just like
> rdtsc(), clflush(), etc.

IOW, like this:

---
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..e2948ce1376c 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -127,14 +127,14 @@ 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 rdpkru();
return 0;
}

static inline void write_pkru(u32 pkru)
{
if (boot_cpu_has(X86_FEATURE_OSPKE))
- __write_pkru(pkru);
+ wrpkru(pkru);
}

static inline int pte_young(pte_t pte)
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index 43c029cdc3fe..396ff572d66a 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 rdpkru(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 wrpkru(u32 pkru)
{
u32 ecx = 0, edx = 0;

@@ -119,12 +119,12 @@ static inline void __write_pkru(u32 pkru)
: : "a" (pkru), "c"(ecx), "d"(edx));
}
#else
-static inline u32 __read_pkru(void)
+static inline u32 rdpkru(void)
{
return 0;
}

-static inline void __write_pkru(u32 pkru)
+static inline void wrpkru(u32 pkru)
{
}
#endif
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ab432a930ae8..85260aa2a920 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6413,7 +6413,7 @@ 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 != vmx->host_pkru)
- __write_pkru(vcpu->arch.pkru);
+ wrpkru(vcpu->arch.pkru);

pt_guest_enter(vmx);

@@ -6501,9 +6501,9 @@ 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 = rdpkru();
if (vcpu->arch.pkru != vmx->host_pkru)
- __write_pkru(vmx->host_pkru);
+ wrpkru(vmx->host_pkru);
}

vmx->nested.nested_run_pending = 0;

--
Regards/Gruss,
Boris.

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