This is the boot message of the virtual machine related to IRQ.
[ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[ 0.000000] GICv3: 224 SPIs implemented
[ 0.000000] GICv3: 0 Extended SPIs implemented
[ 0.000000] GICv3: Distributor has no Range Selector support
[ 0.000000] GICv3: 16 PPIs implemented
[ 0.000000] GICv3: no VLPI support, no direct LPI support
[ 0.000000] GICv3: CPU0: found redistributor 0 region
0:0x00000000080a0000
Somehow the NR_IRQS is 64.
So I tried using SPI 15 which was not assigned. (32 internal IRQs + 15 < 64)
and now request_irq returns 0.
So this irq_desc problem was solved(?) for now. (I don't know why this is so
small when CONFIG_SPARSE_IRQS=y).
And still the handler is not called even when I set qemu_set_irq.
_____________________________________________
From: Chan Kim <c...@etri.re.kr>
Sent: Wednesday, April 6, 2022 10:46 AM
To: 'qemu-discuss' <qemu-discuss@nongnu.org>;
kernelnewb...@kernelnewbies.org
Subject: irq_desc not found for my interrupt number during
request_irq (radix tree of irq_desc has only 64 entries..)
Hello all,
I'm doing an linux driver and application test on a qemu
arm64 virtual machine.
My virtual machine is slightly modified version of arm
'virt' machine and it has our device model included.
When I do request_irq for INTID 208 (SPI 176) in linux on my
arm64 virtual machine, it returns -EINVAL.
I poked into that function and found the desc is returning
NULL in function request_threaded_irq.
int request_threaded_irq(unsigned int irq,
irq_handler_t handler,
irq_handler_t thread_fn, unsigned long
irqflags,
const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
int retval;
...
desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
...
}
and irq_to_desc is supposed to return an irq_desc from the
irq_radix_tree as shown below.
struct irq_desc *irq_to_desc(unsigned int irq)
{
return radix_tree_lookup(&irq_desc_tree, irq);
}
void *radix_tree_lookup(const struct radix_tree_root
*root, unsigned long index)
{
return __radix_tree_lookup(root, index, NULL,
NULL);
}
void *__radix_tree_lookup(const struct
radix_tree_root *root,
unsigned long index, struct
radix_tree_node **nodep,
void __rcu ***slotp)
{
struct radix_tree_node *node, *parent;
unsigned long maxindex;
void __rcu **slot;
restart:
parent = NULL;
slot = (void __rcu **)&root->xa_head;
radix_tree_load_root(root, &node, &maxindex);
if (index > maxindex)
return NULL;
...
}
and I found my request index is 208 but the maxindex of the
radix tree is 63.
So it looks like the radix tree of irq_desc has been set to
have maximum 64 irq_descs.
Where and how can I set this radix tree size?
I looked at qemu's hw/arm/ab21q-build-acpi.c for MADT or
DSDT table parts but couldn't find what to add.
I have my devices address range and irq added in the DSDT
and MADT.
static void
build_dsdt(GArray *table_data, BIOSLinker *linker,
Ab21qMachineState *vms)
{
...
acpi_dsdt_add_axpu(scope, &memmap[AB21Q_AXPU],
(irqmap[AB21Q_AXPU] + ARM_SPI_BASE));
...
}
static void acpi_dsdt_add_axpu(Aml *scope, const MemMapEntry
*axpu_memmap,
uint32_t irq)
{
Aml *dev = aml_device("AXPU");
aml_append(dev, aml_name_decl("_HID",
aml_string("AXPU0011")));
aml_append(dev, aml_name_decl("_UID", aml_int(0)));
Aml *crs = aml_resource_template();
aml_append(crs, aml_memory32_fixed(axpu_memmap->base,
axpu_memmap->size,
AML_READ_WRITE));
aml_append(crs,
aml_interrupt(AML_CONSUMER, AML_LEVEL,
AML_ACTIVE_HIGH,
AML_EXCLUSIVE, &irq, 1));
aml_append(dev, aml_name_decl("_CRS", crs));
aml_append(scope, dev);
}
I'm not sure if I can just use _HID value as "AXPU0011".
If you see anything wrong and have a suggestion, please tell
me.
Thank you!
Chan Kim
