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Subject[PATCH] KVM: arm64: Fix CPUHP logic for protected KVM
From
For protected kvm, the CPU hotplug 'down' logic currently brings
down the timer and vGIC, essentially disabling interrupts. However,
because of how the 'kvm_arm_hardware_enabled' flag is designed, it
never re-enables them back on the CPU hotplug 'up' path. Hence,
clean up the logic to maintain the CPU hotplug up/down symmetry.

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>
---
arch/arm64/kvm/arm.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c2c14059f6a8..010ebfa69650 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1867,14 +1867,10 @@ static void _kvm_arch_hardware_enable(void *discard)

int kvm_arch_hardware_enable(void)
{
- int 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();

return 0;
}
@@ -1889,10 +1885,8 @@ 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);
--
2.41.0.487.g6d72f3e995-goog
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