On 30.09.20 11:16, Juergen Gross wrote:
> Since commit c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data
> to store a per interrupt XEN data pointer which contains XEN specific
> information.")
> Xen is using the chip_data pointer for storing IRQ specific data. When
> running as a HVM domain this can result in problems for legacy IRQs, as
> those might use chip_data for their own purposes.
>
> Use a local array for this purpose in case of legacy IRQs, avoiding the
> double use.
>
> Cc: sta...@vger.kernel.org
> Fixes: c330fb1ddc0a ("XEN uses irqdesc::irq_data_common::handler_data to
> store a per interrupt XEN data pointer which contains XEN specific
> information.")
> Signed-off-by: Juergen Gross <jgr...@suse.com>
Tested-by: Stefan Bader <stefan.ba...@canonical.com>
> ---
> drivers/xen/events/events_base.c | 29 +++++++++++++++++++++--------
> 1 file changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/xen/events/events_base.c
> b/drivers/xen/events/events_base.c
> index 90b8f56fbadb..6f02c18fa65c 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -92,6 +92,8 @@ static bool (*pirq_needs_eoi)(unsigned irq);
> /* Xen will never allocate port zero for any purpose. */
> #define VALID_EVTCHN(chn) ((chn) != 0)
>
> +static struct irq_info *legacy_info_ptrs[NR_IRQS_LEGACY];
> +
> static struct irq_chip xen_dynamic_chip;
> static struct irq_chip xen_percpu_chip;
> static struct irq_chip xen_pirq_chip;
> @@ -156,7 +158,18 @@ int get_evtchn_to_irq(evtchn_port_t evtchn)
> /* Get info for IRQ */
> struct irq_info *info_for_irq(unsigned irq)
> {
> - return irq_get_chip_data(irq);
> + if (irq < nr_legacy_irqs())
> + return legacy_info_ptrs[irq];
> + else
> + return irq_get_chip_data(irq);
> +}
> +
> +static void set_info_for_irq(unsigned int irq, struct irq_info *info)
> +{
> + if (irq < nr_legacy_irqs())
> + legacy_info_ptrs[irq] = info;
> + else
> + irq_set_chip_data(irq, info);
> }
>
> /* Constructors for packed IRQ information. */
> @@ -377,7 +390,7 @@ static void xen_irq_init(unsigned irq)
> info->type = IRQT_UNBOUND;
> info->refcnt = -1;
>
> - irq_set_chip_data(irq, info);
> + set_info_for_irq(irq, info);
>
> list_add_tail(&info->list, &xen_irq_list_head);
> }
> @@ -426,14 +439,14 @@ static int __must_check xen_allocate_irq_gsi(unsigned
> gsi)
>
> static void xen_free_irq(unsigned irq)
> {
> - struct irq_info *info = irq_get_chip_data(irq);
> + struct irq_info *info = info_for_irq(irq);
>
> if (WARN_ON(!info))
> return;
>
> list_del(&info->list);
>
> - irq_set_chip_data(irq, NULL);
> + set_info_for_irq(irq, NULL);
>
> WARN_ON(info->refcnt > 0);
>
> @@ -603,7 +616,7 @@ EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
> static void __unbind_from_irq(unsigned int irq)
> {
> evtchn_port_t evtchn = evtchn_from_irq(irq);
> - struct irq_info *info = irq_get_chip_data(irq);
> + struct irq_info *info = info_for_irq(irq);
>
> if (info->refcnt > 0) {
> info->refcnt--;
> @@ -1108,7 +1121,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
>
> void unbind_from_irqhandler(unsigned int irq, void *dev_id)
> {
> - struct irq_info *info = irq_get_chip_data(irq);
> + struct irq_info *info = info_for_irq(irq);
>
> if (WARN_ON(!info))
> return;
> @@ -1142,7 +1155,7 @@ int evtchn_make_refcounted(evtchn_port_t evtchn)
> if (irq == -1)
> return -ENOENT;
>
> - info = irq_get_chip_data(irq);
> + info = info_for_irq(irq);
>
> if (!info)
> return -ENOENT;
> @@ -1170,7 +1183,7 @@ int evtchn_get(evtchn_port_t evtchn)
> if (irq == -1)
> goto done;
>
> - info = irq_get_chip_data(irq);
> + info = info_for_irq(irq);
>
> if (!info)
> goto done;
> 
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