From 3c8f5965a99397368d3762a9814a21a3e442e1a4 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 16 Oct 2023 12:41:26 +0530 Subject: [PATCH] xen: evtchn: Allow shared registration of IRQ handers [ Upstream commit 9e90e58c11b74c2bddac4b2702cf79d36b981278 ] Currently the handling of events is supported either in the kernel or userspace, but not both. In order to support fast delivery of interrupts from the guest to the backend, we need to handle the Queue notify part of Virtio protocol in kernel and the rest in userspace. Update the interrupt handler registration flag to IRQF_SHARED for event channels, which would allow multiple entities to bind their interrupt handler for the same event channel port. Also increment the reference count of irq_info when multiple entities try to bind event channel to irqchip, so the unbinding happens only after all the users are gone. Signed-off-by: Viresh Kumar Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/99b1edfd3147c6b5d22a5139dab5861e767dc34a.1697439990.git.viresh.kumar@linaro.org Signed-off-by: Juergen Gross Stable-dep-of: fa765c4b4aed ("xen/events: close evtchn after mapping cleanup") Signed-off-by: Sasha Levin --- drivers/xen/events/events_base.c | 3 ++- drivers/xen/evtchn.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index c50419638ac0..cd33a418344a 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1235,7 +1235,8 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip, bind_evtchn_to_cpu(evtchn, 0, false); } else { struct irq_info *info = info_for_irq(irq); - WARN_ON(info == NULL || info->type != IRQT_EVTCHN); + if (!WARN_ON(!info || info->type != IRQT_EVTCHN)) + info->refcnt++; } out: diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index 9139a7364df5..59717628ca42 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -397,7 +397,7 @@ static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port, if (rc < 0) goto err; - rc = bind_evtchn_to_irqhandler_lateeoi(port, evtchn_interrupt, 0, + rc = bind_evtchn_to_irqhandler_lateeoi(port, evtchn_interrupt, IRQF_SHARED, u->name, evtchn); if (rc < 0) goto err;