linux-kernel - [PATCH 3.12 05/63] KVM: ARM: Update comments for kvm_handle

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Date:	Thu, 30 Apr 2015 14:11:34 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	Christoffer Dall <christoffer.dall@...aro.org>,
	Shannon Zhao <shannon.zhao@...aro.org>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 05/63] KVM: ARM: Update comments for kvm_handle_wfi

From: Christoffer Dall <christoffer.dall@...aro.org>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 82ea046c95a3c3ddcfa058c8a270b9afb6e93700 upstream.

Update comments to reflect what is really going on and add the TWE bit
to the comments in kvm_arm.h.

Also renames the function to kvm_handle_wfx like is done on arm64 for
consistency and uber-correctness.

Signed-off-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@...aro.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/arm/include/asm/kvm_arm.h |  1 +
 arch/arm/kvm/handle_exit.c     | 14 ++++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index fe395b7b1ce2..1d3153c7eb41 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -57,6 +57,7 @@
  * TSC:		Trap SMC
  * TSW:		Trap cache operations by set/way
  * TWI:		Trap WFI
+ * TWE:		Trap WFE
  * TIDCP:	Trap L2CTLR/L2ECTLR
  * BSU_IS:	Upgrade barriers to the inner shareable domain
  * FB:		Force broadcast of all maintainance operations
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index c4c496f7619c..a92079011a83 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -73,15 +73,17 @@ static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
 }
 
 /**
- * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest
+ * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
  * @vcpu:	the vcpu pointer
  * @run:	the kvm_run structure pointer
  *
- * Simply sets the wait_for_interrupts flag on the vcpu structure, which will
- * halt execution of world-switches and schedule other host processes until
- * there is an incoming IRQ or FIQ to the VM.
+ * WFE: Yield the CPU and come back to this vcpu when the scheduler
+ * decides to.
+ * WFI: Simply call kvm_vcpu_block(), which will halt execution of
+ * world-switches and schedule other host processes until there is an
+ * incoming IRQ or FIQ to the VM.
  */
-static int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
 	trace_kvm_wfi(*vcpu_pc(vcpu));
 	if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE)
@@ -93,7 +95,7 @@ static int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)
 }
 
 static exit_handle_fn arm_exit_handlers[] = {
-	[HSR_EC_WFI]		= kvm_handle_wfi,
+	[HSR_EC_WFI]		= kvm_handle_wfx,
 	[HSR_EC_CP15_32]	= kvm_handle_cp15_32,
 	[HSR_EC_CP15_64]	= kvm_handle_cp15_64,
 	[HSR_EC_CP14_MR]	= kvm_handle_cp14_access,
-- 
2.3.5

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