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

From: Oliver Upton <oupton@google.com>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Peter Shier <pshier@google.com>,
	Sean Christopherson <seanjc@google.com>,
	David Matlack <dmatlack@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	linux-arm-kernel@lists.infradead.org,
	Jim Mattson <jmattson@google.com>
Subject: [PATCH v8 7/8] KVM: arm64: Configure timer traps in vcpu_load() for VHE
Date: Thu, 16 Sep 2021 18:15:09 +0000	[thread overview]
Message-ID: <20210916181510.963449-8-oupton@google.com> (raw)
In-Reply-To: <20210916181510.963449-1-oupton@google.com>

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 <maz@kernel.org>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 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(-)

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)
-- 
2.33.0.309.g3052b89438-goog

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