[v8,7/8] KVM: arm64: Configure timer traps in vcpu_load() for VHE

Commit Message

Oliver Upton Sept. 16, 2021, 6:15 p.m. UTC

In preparation for emulated physical counter-timer offsetting, configure
traps on every vcpu_load() for VHE systems. As before, these trap
settings do not affect host userspace, and are only active for the
guest.

Suggested-by: Marc Zyngier <[e-mail]>
Signed-off-by: Oliver Upton <[e-mail]>
Reviewed-by: Andrew Jones <[e-mail]>
---
 arch/arm64/kvm/arch_timer.c  | 10 +++++++---
 arch/arm64/kvm/arm.c         |  4 +---
 include/kvm/arm_arch_timer.h |  2 --
 3 files changed, 8 insertions(+), 8 deletions(-)

Patch

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 4bba149d140c..68fb5ddb9e7a 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -51,6 +51,7 @@  static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
 static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
 			      struct arch_timer_context *timer,
 			      enum kvm_arch_timer_regs treg);
+static void kvm_timer_enable_traps_vhe(void);
 
 u32 timer_get_ctl(struct arch_timer_context *ctxt)
 {
@@ -663,6 +664,9 @@  void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 
 	if (map.emul_ptimer)
 		timer_emulate(map.emul_ptimer);
+
+	if (has_vhe())
+		kvm_timer_enable_traps_vhe();
 }
 
 bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu)
@@ -1355,12 +1359,12 @@  int kvm_timer_enable(struct kvm_vcpu *vcpu)
 }
 
 /*
- * On VHE system, we only need to configure the EL2 timer trap register once,
- * not for every world switch.
+ * On VHE system, we only need to configure the EL2 timer trap register on
+ * vcpu_load(), but not every world switch into the guest.
  * The host kernel runs at EL2 with HCR_EL2.TGE == 1,
  * and this makes those bits have no effect for the host kernel execution.
  */
-void kvm_timer_init_vhe(void)
+static void kvm_timer_enable_traps_vhe(void)
 {
 	/* When HCR_EL2.E2H ==1, EL1PCEN and EL1PCTEN are shifted by 10 */
 	u32 cnthctl_shift = 10;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a562b36f28e2..086c9672c8ac 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1590,9 +1590,7 @@  static void cpu_hyp_reinit(void)
 
 	cpu_hyp_reset();
 
-	if (is_kernel_in_hyp_mode())
-		kvm_timer_init_vhe();
-	else
+	if (!is_kernel_in_hyp_mode())
 		cpu_init_hyp_mode();
 
 	cpu_set_hyp_vector();
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index aa666373f603..d06294aa356e 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -87,8 +87,6 @@  u64 kvm_phys_timer_read(void);
 void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu);
 void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);
 
-void kvm_timer_init_vhe(void);
-
 bool kvm_arch_timer_get_input_level(int vintid);
 
 #define vcpu_timer(v)	(&(v)->arch.timer_cpu)