[PATCH v4 12/20] KVM: arm64: Elide kern_hyp_va() in VHE-specific parts of the hypervisor

Marc Zyngier maz at kernel.org
Thu Mar 30 10:47:52 PDT 2023


For VHE-specific hypervisor code, kern_hyp_va() is a NOP.

Actually, it is a whole range of NOPs. It'd be much better if
this code simply didn't exist. Let's just do that.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/include/asm/kvm_mmu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 083cc47dca08..27e63c111f78 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -63,6 +63,7 @@
  * specific registers encoded in the instructions).
  */
 .macro kern_hyp_va	reg
+#ifndef __KVM_VHE_HYPERVISOR__
 alternative_cb ARM64_ALWAYS_SYSTEM, kvm_update_va_mask
 	and     \reg, \reg, #1		/* mask with va_mask */
 	ror	\reg, \reg, #1		/* rotate to the first tag bit */
@@ -70,6 +71,7 @@ alternative_cb ARM64_ALWAYS_SYSTEM, kvm_update_va_mask
 	add	\reg, \reg, #0, lsl 12	/* insert the top 12 bits of the tag */
 	ror	\reg, \reg, #63		/* rotate back */
 alternative_cb_end
+#endif
 .endm
 
 /*
@@ -127,6 +129,7 @@ void kvm_apply_hyp_relocations(void);
 
 static __always_inline unsigned long __kern_hyp_va(unsigned long v)
 {
+#ifndef __KVM_VHE_HYPERVISOR__
 	asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n"
 				    "ror %0, %0, #1\n"
 				    "add %0, %0, #0\n"
@@ -135,6 +138,7 @@ static __always_inline unsigned long __kern_hyp_va(unsigned long v)
 				    ARM64_ALWAYS_SYSTEM,
 				    kvm_update_va_mask)
 		     : "+r" (v));
+#endif
 	return v;
 }
 
-- 
2.34.1




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