When programming ioapic pinX more than once, current code
does not check whether the later attr (trigger&polarity) is the
same as the former or not. This causes a broken semantic.
This can be observed in qemu q35 machine, where ioapic's ioredtbl[x]
can never be set as low-active, even if the hpet driver registered it.
And hpet driver may share a high-level active IRQ line with other
device. So in qemu, when hpet-dev asserts low-level as kernel expects,
the kernel has no response. With this patch, we can observe an
ioredtbl[x] set as low-active for hpet.
Fix it by reporting -EBUSY to the caller, when attr is different.
Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
arch/x86/kernel/acpi/boot.c | 5 ++++-
arch/x86/kernel/apic/io_apic.c | 7 ++++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 230c8ea..9ef2ce9 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1113,6 +1113,7 @@ int mp_register_gsi(struct device *dev, u32 gsi, int
trigger, int polarity)
int ioapic;
int ioapic_pin;
struct io_apic_irq_attr irq_attr;
+ int ret;
if (acpi_irq_model != ACPI_IRQ_MODEL_IOAPIC)
return gsi;
@@ -1142,7 +1143,9 @@ int mp_register_gsi(struct device *dev, u32 gsi, int
trigger, int polarity)
set_io_apic_irq_attr(&irq_attr, ioapic, ioapic_pin,
trigger == ACPI_EDGE_SENSITIVE ? 0 : 1,
polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
- io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+ ret = io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+ if (ret < 0)
+ gsi = INT_MIN;
return gsi;
}
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9ed796c..ce31d902 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3375,12 +3375,17 @@ int io_apic_setup_irq_pin_once(unsigned int irq, int
node,
{
unsigned int ioapic_idx = attr->ioapic, pin = attr->ioapic_pin;
int ret;
+ struct IO_APIC_route_entry orig;
/* Avoid redundant programming */
if (test_bit(pin, ioapics[ioapic_idx].pin_programmed)) {
pr_debug("Pin %d-%d already programmed\n",
mpc_ioapic_id(ioapic_idx), pin);
- return 0;
+ orig = ioapic_read_entry(attr->ioapic, pin);
+ if (attr->trigger == orig.trigger &&
+ attr->polarity == orig.polarity)
+ return 0;
+ return -EBUSY;
}
ret = io_apic_setup_irq_pin(irq, node, attr);
if (!ret)
--
1.8.1.4
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