KVM: arm64: Fix hardware enable/disable flows for pKVM

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@linux.dev>
Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20230719175400.647154-1-rananta@google.com
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 72dc53a75d1c8b09b512f11d06fee248dbe991d3..d8540563a62376340e61f76b92e4a42320e95023 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1874,8 +1874,6 @@ static void _kvm_arch_hardware_enable(void *discard)
 
 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
@@ -1884,13 +1882,10 @@ 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();
 
@@ -1907,10 +1902,8 @@ static void _kvm_arch_hardware_disable(void *discard)
 
 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);