[PATCH 6.4 105/206] KVM: arm64: Fix hardware enable/disable flows for pKVM

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From: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>

commit c718ca0e99401d80d2480c08e1b02cf5f7cd7033 upstream.

When running in protected mode, the hyp stub is disabled after pKVM is
initialized, meaning the host cannot enable/disable the hyp at
runtime. As such, kvm_arm_hardware_enabled is always 1 after
initialization, and kvm_arch_hardware_enable() never enables the vgic
maintenance irq or timer irqs.

Unconditionally enable/disable the vgic + timer irqs in the respective
calls, instead relying on the percpu bookkeeping in the generic code
to keep track of which cpus have the interrupts unmasked.

Fixes: 466d27e48d7c ("KVM: arm64: Simplify the CPUHP logic")
Reported-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Suggested-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230719175400.647154-1-rananta@xxxxxxxxxx
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/kvm/arm.c |   15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1800,8 +1800,6 @@ static void _kvm_arch_hardware_enable(vo
 
 int kvm_arch_hardware_enable(void)
 {
-	int was_enabled;
-
 	/*
 	 * Most calls to this function are made with migration
 	 * disabled, but not with preemption disabled. The former is
@@ -1810,13 +1808,10 @@ int kvm_arch_hardware_enable(void)
 	 */
 	preempt_disable();
 
-	was_enabled = __this_cpu_read(kvm_arm_hardware_enabled);
 	_kvm_arch_hardware_enable(NULL);
 
-	if (!was_enabled) {
-		kvm_vgic_cpu_up();
-		kvm_timer_cpu_up();
-	}
+	kvm_vgic_cpu_up();
+	kvm_timer_cpu_up();
 
 	preempt_enable();
 
@@ -1833,10 +1828,8 @@ static void _kvm_arch_hardware_disable(v
 
 void kvm_arch_hardware_disable(void)
 {
-	if (__this_cpu_read(kvm_arm_hardware_enabled)) {
-		kvm_timer_cpu_down();
-		kvm_vgic_cpu_down();
-	}
+	kvm_timer_cpu_down();
+	kvm_vgic_cpu_down();
 
 	if (!is_protected_kvm_enabled())
 		_kvm_arch_hardware_disable(NULL);





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