Interrupts masked by ICC_PMR_EL1 will not be signaled to the CPU. This means that hypervisor will not receive masked interrupts while running a guest.
Avoid this by making sure ICC_PMR_EL1 is unmasked when we enter a guest. Signed-off-by: Julien Thierry <[email protected]> Cc: Christoffer Dall <[email protected]> Cc: Marc Zyngier <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> Cc: [email protected] --- arch/arm64/include/asm/kvm_host.h | 12 ++++++++++++ arch/arm64/kvm/hyp/switch.c | 16 ++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 52fbc82..5c2fe50 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -24,6 +24,7 @@ #include <linux/types.h> #include <linux/kvm_types.h> +#include <asm/arch_gicv3.h> #include <asm/cpufeature.h> #include <asm/daifflags.h> #include <asm/fpsimd.h> @@ -471,6 +472,17 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) static inline void kvm_arm_vhe_guest_enter(void) { local_daif_mask(); + + /* + * Having IRQs masked via PMR when entering the guest means the GIC + * will not signal the CPU of interrupts of lower priority, and the + * only way to get out will be via guest exceptions. + * Naturally, we want to avoid this. + */ + if (system_uses_irq_prio_masking()) { + gic_write_pmr(GIC_PRIO_IRQON); + dsb(sy); + } } static inline void kvm_arm_vhe_guest_exit(void) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 7cc175c..88ed590 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -22,6 +22,7 @@ #include <kvm/arm_psci.h> +#include <asm/arch_gicv3.h> #include <asm/cpufeature.h> #include <asm/kvm_asm.h> #include <asm/kvm_emulate.h> @@ -537,6 +538,17 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) struct kvm_cpu_context *guest_ctxt; u64 exit_code; + /* + * Having IRQs masked via PMR when entering the guest means the GIC + * will not signal the CPU of interrupts of lower priority, and the + * only way to get out will be via guest exceptions. + * Naturally, we want to avoid this. + */ + if (system_uses_irq_prio_masking()) { + gic_write_pmr(GIC_PRIO_IRQON); + dsb(sy); + } + vcpu = kern_hyp_va(vcpu); host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); @@ -589,6 +601,10 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu) */ __debug_switch_to_host(vcpu); + /* Returning to host will clear PSR.I, remask PMR if needed */ + if (system_uses_irq_prio_masking()) + gic_write_pmr(GIC_PRIO_IRQOFF); + return exit_code; } -- 1.9.1
