From: Jan Kiszka <jan.kis...@siemens.com>
When suspending the CPU while interrupts are passed through, we cannot
simply call wfi as EL2 is not receiving interrupts as wakeup events -
the CPU would starve.
Factor out arm_cpu_passthru_suspend to handle this case by enabling IMO
and FMO before calling wfi. That ensures that EL2 will resume, and as
interrupts are off in that mode, the events will simply be carried to
EL1 when clearing IMO/FMO before returning.
For ARM, arm_cpu_passthru_suspend remains empty as there is no SDEI.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
hypervisor/arch/arm-common/include/asm/control.h | 1 +
hypervisor/arch/arm-common/psci.c | 4 +++-
hypervisor/arch/arm/control.c | 5 +++++
hypervisor/arch/arm64/control.c | 11 +++++++++++
4 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/hypervisor/arch/arm-common/include/asm/control.h
b/hypervisor/arch/arm-common/include/asm/control.h
index 9a5eaba7..acebef32 100644
--- a/hypervisor/arch/arm-common/include/asm/control.h
+++ b/hypervisor/arch/arm-common/include/asm/control.h
@@ -31,6 +31,7 @@ unsigned int arm_cpu_by_mpidr(struct cell *cell, unsigned
long mpidr);
void arm_cpu_reset(unsigned long pc, bool aarch32);
void arm_cpu_park(void);
+void arm_cpu_passthru_suspend(void);
#endif /* !__ASSEMBLY__ */
diff --git a/hypervisor/arch/arm-common/psci.c
b/hypervisor/arch/arm-common/psci.c
index 916a6db9..a0f0b6a7 100644
--- a/hypervisor/arch/arm-common/psci.c
+++ b/hypervisor/arch/arm-common/psci.c
@@ -106,7 +106,9 @@ long psci_dispatch(struct trap_context *ctx)
* a context-preserving suspend. This is legal according to
* PSCI.
*/
- if (!irqchip_has_pending_irqs()) {
+ if (sdei_available) {
+ arm_cpu_passthru_suspend();
+ } else if (!irqchip_has_pending_irqs()) {
asm volatile("wfi" : : : "memory");
irqchip_handle_irq();
}
diff --git a/hypervisor/arch/arm/control.c b/hypervisor/arch/arm/control.c
index 0e7a1b54..46125e1a 100644
--- a/hypervisor/arch/arm/control.c
+++ b/hypervisor/arch/arm/control.c
@@ -101,3 +101,8 @@ void arch_panic_park(void)
arm_write_banked_reg(ELR_hyp, 0);
}
#endif
+
+void arm_cpu_passthru_suspend(void)
+{
+ /* never called */
+}
diff --git a/hypervisor/arch/arm64/control.c b/hypervisor/arch/arm64/control.c
index 3cb5c3f8..5b41b393 100644
--- a/hypervisor/arch/arm64/control.c
+++ b/hypervisor/arch/arm64/control.c
@@ -99,3 +99,14 @@ void arch_panic_park(void)
arm_write_sysreg(ELR_EL2, 0);
}
#endif
+
+void arm_cpu_passthru_suspend(void)
+{
+ unsigned long hcr;
+
+ arm_read_sysreg(HCR_EL2, hcr);
+ arm_write_sysreg(HCR_EL2, hcr | HCR_IMO_BIT | HCR_FMO_BIT);
+ isb();
+ asm volatile("wfi" : : : "memory");
+ arm_write_sysreg(HCR_EL2, hcr);
+}
--
2.26.2
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