Thread (29 messages) 29 messages, 2 authors, 2020-09-22

Re: [PATCH v3 05/11] kvm: arm64: Remove hyp_adr/ldr_this_cpu

From: Will Deacon <will@kernel.org>
Date: 2020-09-18 09:05:41
Also in: kvmarm, lkml

On Wed, Sep 16, 2020 at 06:34:33PM +0100, David Brazdil wrote:
quoted hunk ↗ jump to hunk
The hyp_adr/ldr_this_cpu helpers were introduced for use in hyp code
because they always needed to use TPIDR_EL2 for base, while
adr/ldr_this_cpu from kernel proper would select between TPIDR_EL2 and
_EL1 based on VHE/nVHE.

Simplify this now that the hyp mode case can be handled using the
__KVM_VHE/NVHE_HYPERVISOR__ macros.

Acked-by: Andrew Scull <redacted>
Signed-off-by: David Brazdil <redacted>
---
 arch/arm64/include/asm/assembler.h | 27 +++++++++++++++++----------
 arch/arm64/include/asm/kvm_asm.h   | 14 +-------------
 arch/arm64/kvm/hyp/hyp-entry.S     |  2 +-
 3 files changed, 19 insertions(+), 24 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 54d181177656..f79231a0f949 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -218,6 +218,21 @@ lr	.req	x30		// link register
 	str	\src, [\tmp, :lo12:\sym]
 	.endm
 
+	/*
+	 * @dst: destination register (32 or 64 bit wide)
+	 */
+	.macro	this_cpu_offset, dst
+#if defined(__KVM_NVHE_HYPERVISOR__) || defined(__KVM_VHE_HYPERVISOR__)
+	mrs	\dst, tpidr_el2
+#else
+alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
+	mrs	\dst, tpidr_el1
+alternative_else
+	mrs	\dst, tpidr_el2
+alternative_endif
+#endif
Cosmetic, but I think it would be cleaner just to define two variants of the
macro here:

#if defined(__KVM_NVHE_HYPERVISOR__) || defined(__KVM_VHE_HYPERVISOR__)
	.macro  this_cpu_offset, dst
	mrs     \dst, tpidr_el2
	.endm
#else
	.macro  this_cpu_offset, dst
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
	mrs     \dst, tpidr_el1
alternative_else
	mrs     \dst, tpidr_el2
alternative_endif
	.endm
#endif

(and should we have a shorthand __HYPERVISOR define to avoid the NVHE || VHE
logic?)

With that:

Acked-by: Will Deacon <will@kernel.org>

Will

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