diff options
Diffstat (limited to 'hw/arm/virt.c')
| -rw-r--r-- | hw/arm/virt.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 54498ead23..2ca9527ba4 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -71,6 +71,7 @@ typedef struct { bool disallow_affinity_adjustment; bool no_its; bool no_pmu; + bool claim_edge_triggered_timers; } VirtMachineClass; typedef struct { @@ -309,12 +310,31 @@ static void fdt_add_psci_node(const VirtMachineState *vms) static void fdt_add_timer_nodes(const VirtMachineState *vms, int gictype) { - /* Note that on A15 h/w these interrupts are level-triggered, - * but for the GIC implementation provided by both QEMU and KVM - * they are edge-triggered. + /* On real hardware these interrupts are level-triggered. + * On KVM they were edge-triggered before host kernel version 4.4, + * and level-triggered afterwards. + * On emulated QEMU they are level-triggered. + * + * Getting the DTB info about them wrong is awkward for some + * guest kernels: + * pre-4.8 ignore the DT and leave the interrupt configured + * with whatever the GIC reset value (or the bootloader) left it at + * 4.8 before rc6 honour the incorrect data by programming it back + * into the GIC, causing problems + * 4.8rc6 and later ignore the DT and always write "level triggered" + * into the GIC + * + * For backwards-compatibility, virt-2.8 and earlier will continue + * to say these are edge-triggered, but later machines will report + * the correct information. */ ARMCPU *armcpu; - uint32_t irqflags = GIC_FDT_IRQ_FLAGS_EDGE_LO_HI; + VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms); + uint32_t irqflags = GIC_FDT_IRQ_FLAGS_LEVEL_HI; + + if (vmc->claim_edge_triggered_timers) { + irqflags = GIC_FDT_IRQ_FLAGS_EDGE_LO_HI; + } if (gictype == 2) { irqflags = deposit32(irqflags, GIC_FDT_IRQ_PPI_CPU_START, @@ -1556,8 +1576,14 @@ static void virt_2_8_instance_init(Object *obj) static void virt_machine_2_8_options(MachineClass *mc) { + VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc)); + virt_machine_2_9_options(mc); SET_MACHINE_COMPAT(mc, VIRT_COMPAT_2_8); + /* For 2.8 and earlier we falsely claimed in the DT that + * our timers were edge-triggered, not level-triggered. + */ + vmc->claim_edge_triggered_timers = true; } DEFINE_VIRT_MACHINE(2, 8) |