linux-kernel - [PATCH] KVM: arm64: fix misleading comments in save/restore

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Message-Id: <1432806186-27993-1-git-send-email-alex.bennee@linaro.org>
Date:	Thu, 28 May 2015 10:43:06 +0100
From:	Alex Bennée <alex.bennee@...aro.org>
To:	marc.zyngier@....com
Cc:	christoffer.dall@...aro.org, kvm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
	Alex Bennée <alex.bennee@...aro.org>,
	Gleb Natapov <gleb@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] KVM: arm64: fix misleading comments in save/restore

The elr_el2 and spsr_el2 registers in fact contain the processor state
before entry into the hypervisor code. In the case of guest state it
could be in either el0 or el1.

Signed-off-by: Alex Bennée <alex.bennee@...aro.org>
---
 arch/arm64/kvm/hyp.S | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index d755922..1940a4c 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -50,8 +50,8 @@
 	stp	x29, lr, [x3, #80]
 
 	mrs	x19, sp_el0
-	mrs	x20, elr_el2		// EL1 PC
-	mrs	x21, spsr_el2		// EL1 pstate
+	mrs	x20, elr_el2		// PC before hyp entry
+	mrs	x21, spsr_el2		// pstate before hyp entry
 
 	stp	x19, x20, [x3, #96]
 	str	x21, [x3, #112]
@@ -82,8 +82,8 @@
 	ldr	x21, [x3, #16]
 
 	msr	sp_el0, x19
-	msr	elr_el2, x20 				// EL1 PC
-	msr	spsr_el2, x21 				// EL1 pstate
+	msr	elr_el2, x20 		// PC to restore
+	msr	spsr_el2, x21 		// pstate to restore
 
 	add	x3, x2, #CPU_XREG_OFFSET(19)
 	ldp	x19, x20, [x3]
-- 
2.4.1

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