Do some cleanups in Xen event handling code.
Juergen Gross (5):
xen: remove no longer used functions
xen/events: make struct irq_info private to events_base.c
xen/events: only register debug interrupt for 2-level events
xen/events: unmask a fifo event channel only if it was masked
Documentation: add xen.fifo_events kernel parameter description
.../admin-guide/kernel-parameters.txt | 7 ++
arch/x86/xen/smp.c | 19 ++--
arch/x86/xen/xen-ops.h | 2 +
drivers/xen/events/events_2l.c | 7 +-
drivers/xen/events/events_base.c | 90 +++++++++++++------
drivers/xen/events/events_fifo.c | 9 +-
drivers/xen/events/events_internal.h | 70 ++-------------
include/xen/events.h | 8 --
8 files changed, 100 insertions(+), 112 deletions(-)
--
2.26.2
The kernel boot parameter xen.fifo_events isn't listed in
Documentation/admin-guide/kernel-parameters.txt. Add it.
Signed-off-by: Juergen Gross <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 02d4adbf98d2..526d65d8573a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5978,6 +5978,13 @@
After which time (jiffies) the event handling loop
should start to delay EOI handling. Default is 2.
+ xen.fifo_events= [XEN]
+ Boolean parameter to disable using fifo event handling
+ even if available. Normally fifo event handling is
+ preferred over the 2-level event handling, as it is
+ fairer and the number of possible event channels is
+ much higher. Default is on (use fifo events).
+
nopv= [X86,XEN,KVM,HYPER_V,VMWARE]
Disables the PV optimizations forcing the guest to run
as generic guest with no PV drivers. Currently support
--
2.26.2
On 22.10.2020 09:42, Juergen Gross wrote:
> Do some cleanups in Xen event handling code.
>
> Juergen Gross (5):
> xen: remove no longer used functions
> xen/events: make struct irq_info private to events_base.c
> xen/events: only register debug interrupt for 2-level events
> xen/events: unmask a fifo event channel only if it was masked
> Documentation: add xen.fifo_events kernel parameter description
With the two remarks to individual patches suitably taken care of
one way or another
Reviewed-by: Jan Beulich <[email protected]>
Jan
With the switch to the lateeoi model for interdomain event channels
some functions are no longer in use. Remove them.
Suggested-by: Jan Beulich <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/events/events_base.c | 21 ---------------------
include/xen/events.h | 8 --------
2 files changed, 29 deletions(-)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index cc317739e786..436682db41c5 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1145,14 +1145,6 @@ static int bind_interdomain_evtchn_to_irq_chip(unsigned int remote_domain,
chip);
}
-int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
- evtchn_port_t remote_port)
-{
- return bind_interdomain_evtchn_to_irq_chip(remote_domain, remote_port,
- &xen_dynamic_chip);
-}
-EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq);
-
int bind_interdomain_evtchn_to_irq_lateeoi(unsigned int remote_domain,
evtchn_port_t remote_port)
{
@@ -1320,19 +1312,6 @@ static int bind_interdomain_evtchn_to_irqhandler_chip(
return irq;
}
-int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
- evtchn_port_t remote_port,
- irq_handler_t handler,
- unsigned long irqflags,
- const char *devname,
- void *dev_id)
-{
- return bind_interdomain_evtchn_to_irqhandler_chip(remote_domain,
- remote_port, handler, irqflags, devname,
- dev_id, &xen_dynamic_chip);
-}
-EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irqhandler);
-
int bind_interdomain_evtchn_to_irqhandler_lateeoi(unsigned int remote_domain,
evtchn_port_t remote_port,
irq_handler_t handler,
diff --git a/include/xen/events.h b/include/xen/events.h
index 3b8155c2ea03..8ec418e30c7f 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -35,16 +35,8 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
unsigned long irqflags,
const char *devname,
void *dev_id);
-int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
- evtchn_port_t remote_port);
int bind_interdomain_evtchn_to_irq_lateeoi(unsigned int remote_domain,
evtchn_port_t remote_port);
-int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
- evtchn_port_t remote_port,
- irq_handler_t handler,
- unsigned long irqflags,
- const char *devname,
- void *dev_id);
int bind_interdomain_evtchn_to_irqhandler_lateeoi(unsigned int remote_domain,
evtchn_port_t remote_port,
irq_handler_t handler,
--
2.26.2
Unmasking an event channel with fifo events channels being used can
require a hypercall to be made, so try to avoid that by checking
whether the event channel was really masked.
Suggested-by: Jan Beulich <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/events/events_fifo.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 243e7b6d7b96..f60c5a9ec833 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word)
w = *word;
+ if (!(w & (1 << EVTCHN_FIFO_MASKED)))
+ return true;
+
do {
if (w & (1 << EVTCHN_FIFO_PENDING))
return false;
--
2.26.2
The struct irq_info of Xen's event handling is used only for two
evtchn_ops functions outside of events_base.c. Those two functions
can easily be switched to avoid that usage.
This allows to make struct irq_info and its related access functions
private to events_base.c.
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/events/events_2l.c | 7 +--
drivers/xen/events/events_base.c | 63 ++++++++++++++++++++++---
drivers/xen/events/events_fifo.c | 6 +--
drivers/xen/events/events_internal.h | 70 ++++------------------------
4 files changed, 73 insertions(+), 73 deletions(-)
diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
index fe5ad0e89cd8..da87f3a1e351 100644
--- a/drivers/xen/events/events_2l.c
+++ b/drivers/xen/events/events_2l.c
@@ -47,10 +47,11 @@ static unsigned evtchn_2l_max_channels(void)
return EVTCHN_2L_NR_CHANNELS;
}
-static void evtchn_2l_bind_to_cpu(struct irq_info *info, unsigned cpu)
+static void evtchn_2l_bind_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
+ unsigned int old_cpu)
{
- clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu)));
- set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
+ clear_bit(evtchn, BM(per_cpu(cpu_evtchn_mask, old_cpu)));
+ set_bit(evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
}
static void evtchn_2l_clear_pending(evtchn_port_t port)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 436682db41c5..1c25580c7691 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -70,6 +70,57 @@
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "xen."
+/* Interrupt types. */
+enum xen_irq_type {
+ IRQT_UNBOUND = 0,
+ IRQT_PIRQ,
+ IRQT_VIRQ,
+ IRQT_IPI,
+ IRQT_EVTCHN
+};
+
+/*
+ * Packed IRQ information:
+ * type - enum xen_irq_type
+ * event channel - irq->event channel mapping
+ * cpu - cpu this event channel is bound to
+ * index - type-specific information:
+ * PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
+ * guest, or GSI (real passthrough IRQ) of the device.
+ * VIRQ - virq number
+ * IPI - IPI vector
+ * EVTCHN -
+ */
+struct irq_info {
+ struct list_head list;
+ struct list_head eoi_list;
+ short refcnt;
+ short spurious_cnt;
+ enum xen_irq_type type; /* type */
+ unsigned irq;
+ evtchn_port_t evtchn; /* event channel */
+ unsigned short cpu; /* cpu bound */
+ unsigned short eoi_cpu; /* EOI must happen on this cpu-1 */
+ unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
+ u64 eoi_time; /* Time in jiffies when to EOI. */
+
+ union {
+ unsigned short virq;
+ enum ipi_vector ipi;
+ struct {
+ unsigned short pirq;
+ unsigned short gsi;
+ unsigned char vector;
+ unsigned char flags;
+ uint16_t domid;
+ } pirq;
+ } u;
+};
+
+#define PIRQ_NEEDS_EOI (1 << 0)
+#define PIRQ_SHAREABLE (1 << 1)
+#define PIRQ_MSI_GROUP (1 << 2)
+
static uint __read_mostly event_loop_timeout = 2;
module_param(event_loop_timeout, uint, 0644);
@@ -110,7 +161,7 @@ static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
/* IRQ <-> IPI mapping */
static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
-int **evtchn_to_irq;
+static int **evtchn_to_irq;
#ifdef CONFIG_X86
static unsigned long *pirq_eoi_map;
#endif
@@ -190,7 +241,7 @@ int get_evtchn_to_irq(evtchn_port_t evtchn)
}
/* Get info for IRQ */
-struct irq_info *info_for_irq(unsigned irq)
+static struct irq_info *info_for_irq(unsigned irq)
{
if (irq < nr_legacy_irqs())
return legacy_info_ptrs[irq];
@@ -228,7 +279,7 @@ static int xen_irq_info_common_setup(struct irq_info *info,
irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
- return xen_evtchn_port_setup(info);
+ return xen_evtchn_port_setup(evtchn);
}
static int xen_irq_info_evtchn_setup(unsigned irq,
@@ -351,7 +402,7 @@ static enum xen_irq_type type_from_irq(unsigned irq)
return info_for_irq(irq)->type;
}
-unsigned cpu_from_irq(unsigned irq)
+static unsigned cpu_from_irq(unsigned irq)
{
return info_for_irq(irq)->cpu;
}
@@ -391,7 +442,7 @@ static void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu)
#ifdef CONFIG_SMP
cpumask_copy(irq_get_affinity_mask(irq), cpumask_of(cpu));
#endif
- xen_evtchn_port_bind_to_cpu(info, cpu);
+ xen_evtchn_port_bind_to_cpu(evtchn, cpu, info->cpu);
info->cpu = cpu;
}
@@ -745,7 +796,7 @@ static unsigned int __startup_pirq(unsigned int irq)
info->evtchn = evtchn;
bind_evtchn_to_cpu(evtchn, 0);
- rc = xen_evtchn_port_setup(info);
+ rc = xen_evtchn_port_setup(evtchn);
if (rc)
goto err;
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index 6085a808da95..243e7b6d7b96 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -138,9 +138,8 @@ static void init_array_page(event_word_t *array_page)
array_page[i] = 1 << EVTCHN_FIFO_MASKED;
}
-static int evtchn_fifo_setup(struct irq_info *info)
+static int evtchn_fifo_setup(evtchn_port_t port)
{
- evtchn_port_t port = info->evtchn;
unsigned new_array_pages;
int ret;
@@ -186,7 +185,8 @@ static int evtchn_fifo_setup(struct irq_info *info)
return ret;
}
-static void evtchn_fifo_bind_to_cpu(struct irq_info *info, unsigned cpu)
+static void evtchn_fifo_bind_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
+ unsigned int old_cpu)
{
/* no-op */
}
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 82937d90d7d7..0a97c0549db7 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -7,65 +7,15 @@
#ifndef __EVENTS_INTERNAL_H__
#define __EVENTS_INTERNAL_H__
-/* Interrupt types. */
-enum xen_irq_type {
- IRQT_UNBOUND = 0,
- IRQT_PIRQ,
- IRQT_VIRQ,
- IRQT_IPI,
- IRQT_EVTCHN
-};
-
-/*
- * Packed IRQ information:
- * type - enum xen_irq_type
- * event channel - irq->event channel mapping
- * cpu - cpu this event channel is bound to
- * index - type-specific information:
- * PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
- * guest, or GSI (real passthrough IRQ) of the device.
- * VIRQ - virq number
- * IPI - IPI vector
- * EVTCHN -
- */
-struct irq_info {
- struct list_head list;
- struct list_head eoi_list;
- short refcnt;
- short spurious_cnt;
- enum xen_irq_type type; /* type */
- unsigned irq;
- evtchn_port_t evtchn; /* event channel */
- unsigned short cpu; /* cpu bound */
- unsigned short eoi_cpu; /* EOI must happen on this cpu */
- unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
- u64 eoi_time; /* Time in jiffies when to EOI. */
-
- union {
- unsigned short virq;
- enum ipi_vector ipi;
- struct {
- unsigned short pirq;
- unsigned short gsi;
- unsigned char vector;
- unsigned char flags;
- uint16_t domid;
- } pirq;
- } u;
-};
-
-#define PIRQ_NEEDS_EOI (1 << 0)
-#define PIRQ_SHAREABLE (1 << 1)
-#define PIRQ_MSI_GROUP (1 << 2)
-
struct evtchn_loop_ctrl;
struct evtchn_ops {
unsigned (*max_channels)(void);
unsigned (*nr_channels)(void);
- int (*setup)(struct irq_info *info);
- void (*bind_to_cpu)(struct irq_info *info, unsigned cpu);
+ int (*setup)(evtchn_port_t port);
+ void (*bind_to_cpu)(evtchn_port_t evtchn, unsigned int cpu,
+ unsigned int old_cpu);
void (*clear_pending)(evtchn_port_t port);
void (*set_pending)(evtchn_port_t port);
@@ -83,12 +33,9 @@ struct evtchn_ops {
extern const struct evtchn_ops *evtchn_ops;
-extern int **evtchn_to_irq;
int get_evtchn_to_irq(evtchn_port_t evtchn);
void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl);
-struct irq_info *info_for_irq(unsigned irq);
-unsigned cpu_from_irq(unsigned irq);
unsigned int cpu_from_evtchn(evtchn_port_t evtchn);
static inline unsigned xen_evtchn_max_channels(void)
@@ -100,17 +47,18 @@ static inline unsigned xen_evtchn_max_channels(void)
* Do any ABI specific setup for a bound event channel before it can
* be unmasked and used.
*/
-static inline int xen_evtchn_port_setup(struct irq_info *info)
+static inline int xen_evtchn_port_setup(evtchn_port_t evtchn)
{
if (evtchn_ops->setup)
- return evtchn_ops->setup(info);
+ return evtchn_ops->setup(evtchn);
return 0;
}
-static inline void xen_evtchn_port_bind_to_cpu(struct irq_info *info,
- unsigned cpu)
+static inline void xen_evtchn_port_bind_to_cpu(evtchn_port_t evtchn,
+ unsigned int cpu,
+ unsigned int old_cpu)
{
- evtchn_ops->bind_to_cpu(info, cpu);
+ evtchn_ops->bind_to_cpu(evtchn, cpu, old_cpu);
}
static inline void clear_evtchn(evtchn_port_t port)
--
2.26.2