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 <[email protected]>
Suggested-by: Oliver Upton <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
---
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
On Wed, 19 Jul 2023 22:57:25 +0100,
Raghavendra Rao Ananta <[email protected]> wrote:
>
> 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 <[email protected]>
> Suggested-by: Oliver Upton <[email protected]>
> Signed-off-by: Raghavendra Rao Ananta <[email protected]>
> ---
> 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);
Note that this will likely conflict with the preemption disabling
patch that is on its way to upstream. Otherwise:
Acked-by: Marc Zyngier <[email protected]>
M.
--
Without deviation from the norm, progress is not possible.
On Wed, 19 Jul 2023 21:57:25 +0000, Raghavendra Rao Ananta wrote:
> 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.
>
> [...]
Applied to kvmarm/fixes, thanks!
[1/1] KVM: arm64: Fix hardware enable/disable flows for pKVM
https://git.kernel.org/kvmarm/kvmarm/c/c718ca0e9940
--
Best,
Oliver