From e5fc7345412d5e4758fcef55a74354c5cbefd61e Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Wed, 1 Dec 2010 14:51:44 +0000 Subject: [PATCH] xen: use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the amount of pirq available. This fixes find_unbound_pirq that otherwise would return a number starting from nr_irqs that might very well be out of range in Xen. The symptom of this bug is that when you passthrough an MSI capable pci device to a PV on HVM guest, Linux would fail to enable MSIs on the device. Signed-off-by: Stefano Stabellini --- drivers/xen/events.c | 45 +++++++++++++++------------------ include/xen/interface/physdev.h | 10 ++++++++ 2 files changed, 30 insertions(+), 25 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 2811bb988ea..7ab43c33f74 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -105,7 +105,6 @@ struct irq_info static struct irq_info *irq_info; static int *pirq_to_irq; -static int nr_pirqs; static int *evtchn_to_irq; struct cpu_evtchn_s { @@ -385,12 +384,17 @@ static int get_nr_hw_irqs(void) return ret; } -/* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs - * succeeded otherwise nr_pirqs won't hold the right value */ -static int find_unbound_pirq(void) +static int find_unbound_pirq(int type) { - int i; - for (i = nr_pirqs-1; i >= 0; i--) { + int rc, i; + struct physdev_get_free_pirq op_get_free_pirq; + op_get_free_pirq.type = type; + + rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq); + if (!rc) + return op_get_free_pirq.pirq; + + for (i = 0; i < nr_irqs; i++) { if (pirq_to_irq[i] < 0) return i; } @@ -611,10 +615,10 @@ int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name) spin_lock(&irq_mapping_update_lock); - if ((pirq > nr_pirqs) || (gsi > nr_irqs)) { + if ((pirq > nr_irqs) || (gsi > nr_irqs)) { printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n", - pirq > nr_pirqs ? "nr_pirqs" :"", - gsi > nr_irqs ? "nr_irqs" : ""); + pirq > nr_irqs ? "pirq" :"", + gsi > nr_irqs ? "gsi" : ""); goto out; } @@ -672,7 +676,7 @@ void xen_allocate_pirq_msi(char *name, int *irq, int *pirq) if (*irq == -1) goto out; - *pirq = find_unbound_pirq(); + *pirq = find_unbound_pirq(MAP_PIRQ_TYPE_MSI); if (*pirq == -1) goto out; @@ -1506,26 +1510,17 @@ void xen_callback_vector(void) {} void __init xen_init_IRQ(void) { - int i, rc; - struct physdev_nr_pirqs op_nr_pirqs; + int i; cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s), GFP_KERNEL); irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL); - rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs); - if (rc < 0) { - nr_pirqs = nr_irqs; - if (rc != -ENOSYS) - printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc); - } else { - if (xen_pv_domain() && !xen_initial_domain()) - nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs); - else - nr_pirqs = op_nr_pirqs.nr_pirqs; - } - pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL); - for (i = 0; i < nr_pirqs; i++) + /* We are using nr_irqs as the maximum number of pirq available but + * that number is actually chosen by Xen and we don't know exactly + * what it is. Be careful choosing high pirq numbers. */ + pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL); + for (i = 0; i < nr_irqs; i++) pirq_to_irq[i] = -1; evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq), diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h index 2b2c66c3df0..534cac89a77 100644 --- a/include/xen/interface/physdev.h +++ b/include/xen/interface/physdev.h @@ -188,6 +188,16 @@ struct physdev_nr_pirqs { uint32_t nr_pirqs; }; +/* type is MAP_PIRQ_TYPE_GSI or MAP_PIRQ_TYPE_MSI + * the hypercall returns a free pirq */ +#define PHYSDEVOP_get_free_pirq 23 +struct physdev_get_free_pirq { + /* IN */ + int type; + /* OUT */ + uint32_t pirq; +}; + /* * Notify that some PIRQ-bound event channels have been unmasked. * ** This command is obsolete since interface version 0x00030202 and is ** -- 2.20.1