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* [PATCH] KVM: arm64: Simplify __kvm_timer_set_cntvoff implementation
@ 2020-05-13 12:15 Marc Zyngier
  0 siblings, 0 replies; only message in thread
From: Marc Zyngier @ 2020-05-13 12:15 UTC (permalink / raw)
  To: kvm, kvmarm, linux-arm-kernel

Now that this function isn't constrained by the 32bit PCS,
let's simplify it by taking a single 64bit offset instead
of two 32bit parameters.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_asm.h |  2 +-
 virt/kvm/arm/arch_timer.c        | 12 +-----------
 virt/kvm/arm/hyp/timer-sr.c      |  3 +--
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 7c7eeeaab9fa..59e314f38e43 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -64,7 +64,7 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
 extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
 extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
 
-extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
+extern void __kvm_timer_set_cntvoff(u64 cntvoff);
 
 extern int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu);
 
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 93bd59b46848..487eba9f87cd 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -451,17 +451,7 @@ static void timer_restore_state(struct arch_timer_context *ctx)
 
 static void set_cntvoff(u64 cntvoff)
 {
-	u32 low = lower_32_bits(cntvoff);
-	u32 high = upper_32_bits(cntvoff);
-
-	/*
-	 * Since kvm_call_hyp doesn't fully support the ARM PCS especially on
-	 * 32-bit systems, but rather passes register by register shifted one
-	 * place (we put the function address in r0/x0), we cannot simply pass
-	 * a 64-bit value as an argument, but have to split the value in two
-	 * 32-bit halves.
-	 */
-	kvm_call_hyp(__kvm_timer_set_cntvoff, low, high);
+	kvm_call_hyp(__kvm_timer_set_cntvoff, cntvoff);
 }
 
 static inline void set_timer_irq_phys_active(struct arch_timer_context *ctx, bool active)
diff --git a/virt/kvm/arm/hyp/timer-sr.c b/virt/kvm/arm/hyp/timer-sr.c
index ff76e6845fe4..fb5c0be33223 100644
--- a/virt/kvm/arm/hyp/timer-sr.c
+++ b/virt/kvm/arm/hyp/timer-sr.c
@@ -10,9 +10,8 @@
 
 #include <asm/kvm_hyp.h>
 
-void __hyp_text __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high)
+void __hyp_text __kvm_timer_set_cntvoff(u64 cntvoff)
 {
-	u64 cntvoff = (u64)cntvoff_high << 32 | cntvoff_low;
 	write_sysreg(cntvoff, cntvoff_el2);
 }
 
-- 
2.20.1

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2020-05-13 12:15 [PATCH] KVM: arm64: Simplify __kvm_timer_set_cntvoff implementation Marc Zyngier

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