Messages in this thread | | | Subject | Re: [PATCH 1/1] irqdomain: Export __irq_domain_alloc_irqs() and irq_domain_free_irqs() | From | Alexander Popov <> | Date | Mon, 18 Jul 2016 15:34:35 +0300 |
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On 16.07.2016 11:22, Marc Zyngier wrote: > On Sat, 16 Jul 2016 04:33:59 +0300 > Alexander Popov <alex.popov@linux.com> wrote: > >> On 08.07.2016 11:34, Alexander Popov wrote: >>> On 06.07.2016 14:17, Thomas Gleixner wrote: >>>> On Fri, 1 Jul 2016, Alexander Popov wrote: >>>> >>>>> Export __irq_domain_alloc_irqs() and irq_domain_free_irqs() for being >>>>> able to work with irq_domain hierarchy in modules. >>>> >>>> We usually export only when we have a proper use case which is supposed to go >>>> into the kernel tree proper. What's yours?
...
>> Did I properly answer your question? Will you accept my patch exporting these >> two functions? > > I think that without any in-tree modular users of these symbols, the > incentive for exporting those is pretty low. I can't really say > anything about your particular use-case, but I'd really to see some > code before taking that kind of patch.
Thanks for your answer, Mark.
Here is the module which uses __irq_domain_alloc_irqs() and irq_domain_free_irqs() and allows registering IRQ handlers for interrupts injected by the hypervisor on x86_64. Large hypervisors usually emulate an MSI-capable PCI device to do this job, but that way is inappropriate for lightweight hypervisors.
/* * The module is for registering IRQ handlers for interrupts injected * by the hypervisor using Intel VT-x technology. This module targets * x86_64 platform. * * It works fine if __irq_domain_alloc_irqs() and irq_domain_free_irqs() * are exported. */
#include <linux/module.h> #include <linux/irq.h> #include <linux/irqdesc.h> #include <linux/irqnr.h> #include <linux/irqdomain.h> #include <linux/interrupt.h> #include <asm/hw_irq.h> #include <asm/irqdomain.h>
#define PARAVIRT_IRQS_N 10
struct irq_domain *paravirq_domain = NULL; static int paravirq_irqbase = -EINVAL; static int paravirq_irqs[PARAVIRT_IRQS_N] = {[0 ... PARAVIRT_IRQS_N - 1] = -EINVAL};
static irqreturn_t paravirq_irq_handler(int irq, void *cookie) { printk("\tparavirq_irq_handler: virq %d\n", irq);
/* ... some job ... */
return IRQ_HANDLED; }
static void paravirq_chip_irq_mask(struct irq_data *data) { printk("\tparavirq_chip_irq_mask\n");
/* ... tell the hypervisor not to inject the interrupt ... */ }
static void paravirq_chip_irq_unmask(struct irq_data *data) { printk("\tparavirq_chip_irq_UNmask\n");
/* ... allow the hypervisor to inject the interrupt ... */ }
static void paravirq_chip_ack(struct irq_data *data) { data = data->parent_data; data->chip->irq_ack(data); }
static struct irq_chip paravirq_chip __read_mostly = { .name = "PARAVIRQ", .irq_mask = paravirq_chip_irq_mask, .irq_unmask = paravirq_chip_irq_unmask, .irq_ack = paravirq_chip_ack, };
static int paravirq_domain_alloc(struct irq_domain *domain, unsigned int virq, unsigned int nr_irqs, void *arg) { int ret = 0; unsigned int i = 0; unsigned int irq = 0;
printk("\tparavirq_domain_alloc: virq %u, nr_irqs %u, arg 0x%p\n", virq, nr_irqs, arg); for (i = 0; i < nr_irqs; i++) { irq = virq + i;
ret = irq_domain_set_hwirq_and_chip(domain, irq, i, ¶virq_chip, NULL); if (ret) { printk("\t\tsetting chip, hwirq for %d failed\n", irq); return ret; }
__irq_set_handler(irq, handle_edge_irq, 0, "edge"); }
return 0; }
static void paravirq_domain_free(struct irq_domain *domain, unsigned int virq, unsigned int nr_irqs) { int ret = 0; unsigned int i = 0; unsigned int irq = 0;
printk("\tparavirq_domain_free: virq %u, nr_irqs %u\n", virq, nr_irqs);
for (i = 0; i < nr_irqs; i++) { irq = virq + i;
ret = irq_set_chip(irq, NULL); if (ret) printk("\t\tunsetting chip for %d failed\n", irq); } }
const struct irq_domain_ops paravirq_irqdomain_ops = { .alloc = paravirq_domain_alloc, .free = paravirq_domain_free, };
static int __init paravirq_init(void) { int ret = 0; int i = 0; struct irq_alloc_info info = { 0 }; struct irq_cfg *cfg = NULL;
printk("paravirq_init\n");
paravirq_domain = irq_domain_add_linear(NULL, PARAVIRT_IRQS_N, ¶virq_irqdomain_ops, NULL); if (!paravirq_domain) { ret = -ENOMEM; goto err0; }
paravirq_domain->name = paravirq_chip.name; paravirq_domain->parent = x86_vector_domain; paravirq_domain->flags |= IRQ_DOMAIN_FLAG_AUTO_RECURSIVE; printk("\tparavirq_domain %s (0x%p) is created\n", paravirq_domain->name, paravirq_domain);
printk("\tcall irq_domain_alloc_irqs with info 0x%p\n", &info); paravirq_irqbase = irq_domain_alloc_irqs(paravirq_domain, PARAVIRT_IRQS_N, NUMA_NO_NODE, &info); if (paravirq_irqbase < 0) { printk("\tallocating irqs failed: %d\n", paravirq_irqbase); ret = paravirq_irqbase; goto err1; }
printk("\tsuccessfully allocated %d irqs beginning from %d\n", PARAVIRT_IRQS_N, paravirq_irqbase);
for (i = 0; i < PARAVIRT_IRQS_N; i++) { int irq = paravirq_irqbase + i;
ret = request_irq(irq, paravirq_irq_handler, 0, "paravirq_mod", NULL); if (ret) { printk("\trequest_irq %d failed: %d\n", irq, ret); goto err2; } else { printk("\tvirq %d is requested!\n", irq); paravirq_irqs[i] = irq; } }
printk("\tSo, paravirq_mod grabbed %d irqs:\n", PARAVIRT_IRQS_N); for (i = 0; i < PARAVIRT_IRQS_N; i++) { cfg = irqd_cfg(irq_get_irq_data(paravirq_irqs[i])); if (!cfg) { printk("\t\tirq #%d: NULL irq_cfg\n", paravirq_irqs[i]); goto err2; }
printk("\t\tirq #%d: virq %d, vector %d\n", i, paravirq_irqs[i], cfg->vector); }
return 0;
err2: for (i = 0; i < PARAVIRT_IRQS_N; i++) { if (paravirq_irqs[i] >= 0) { printk("\tfreeing virq %d\n", paravirq_irqs[i]); free_irq(paravirq_irqs[i], NULL); } } irq_domain_free_irqs(paravirq_irqbase, PARAVIRT_IRQS_N); err1: irq_domain_remove(paravirq_domain); err0: return ret; }
static void __exit paravirq_exit(void) { int i;
printk("paravirq_exit\n");
for (i = 0; i < PARAVIRT_IRQS_N; i++) { if (paravirq_irqs[i] > 0) { printk("\tfreeing virq %d\n", paravirq_irqs[i]); free_irq(paravirq_irqs[i], NULL); } }
if (paravirq_irqbase >= 0) irq_domain_free_irqs(paravirq_irqbase, PARAVIRT_IRQS_N);
if (paravirq_domain) irq_domain_remove(paravirq_domain); }
module_init(paravirq_init) module_exit(paravirq_exit)
MODULE_AUTHOR("Alexander Popov <alex.popov@linux.com>"); MODULE_DESCRIPTION("The module for handling interrupts from the hypervisor"); MODULE_LICENSE("GPL v2");
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