From: David Woodhouse <d...@amazon.co.uk>
The default number of PIRQs is set to 256 to avoid issues with 32-bit MSI
devices. Allow it to be increased if the user desires.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Reviewed-by: Paul Durrant <p...@xen.org>
---
accel/kvm/kvm-all.c | 1 +
hw/i386/kvm/xen_evtchn.c | 21 +++++++++++----------
include/sysemu/kvm_int.h | 1 +
include/sysemu/kvm_xen.h | 1 +
target/i386/kvm/kvm.c | 34 ++++++++++++++++++++++++++++++++++
target/i386/kvm/xen-emu.c | 6 ++++++
6 files changed, 54 insertions(+), 10 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index dc5b0bb434..3b7881e949 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -3705,6 +3705,7 @@ static void kvm_accel_instance_init(Object *obj)
s->notify_window = 0;
s->xen_version = 0;
s->xen_gnttab_max_frames = 64;
+ s->xen_evtchn_max_pirq = 256;
}
/**
diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
index 4ec0c7af75..3f60461e5c 100644
--- a/hw/i386/kvm/xen_evtchn.c
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -302,17 +302,18 @@ void xen_evtchn_create(void)
}
/*
- * We could parameterise the number of PIRQs available if needed,
- * but for now limit it to 256. The Xen scheme for encoding PIRQ#
- * into an MSI message is not compatible with 32-bit MSI, as it
- * puts the high bits of the PIRQ# into the high bits of the MSI
- * message address, instead of using the Extended Destination ID
- * in address bits 4-11 which perhaps would have been a better
- * choice. So to keep life simple, just stick with 256 as the
- * default, which conveniently doesn't need to set anything
- * outside the low 32 bits of the address.
+ * The Xen scheme for encoding PIRQ# into an MSI message is not
+ * compatible with 32-bit MSI, as it puts the high bits of the
+ * PIRQ# into the high bits of the MSI message address, instead of
+ * using the Extended Destination ID in address bits 4-11 which
+ * perhaps would have been a better choice.
+ *
+ * To keep life simple, kvm_accel_instance_init() initialises the
+ * default to 256. which conveniently doesn't need to set anything
+ * outside the low 32 bits of the address. It can be increased by
+ * setting the xen-evtchn-max-pirq property.
*/
- s->nr_pirqs = 256;
+ s->nr_pirqs = kvm_xen_get_evtchn_max_pirq();
s->nr_pirq_inuse_words = DIV_ROUND_UP(s->nr_pirqs, 64);
s->pirq_inuse_bitmap = g_new0(uint64_t, s->nr_pirq_inuse_words);
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 39ce4d36f6..a641c974ea 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -121,6 +121,7 @@ struct KVMState
uint32_t xen_version;
uint32_t xen_caps;
uint16_t xen_gnttab_max_frames;
+ uint16_t xen_evtchn_max_pirq;
};
void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
diff --git a/include/sysemu/kvm_xen.h b/include/sysemu/kvm_xen.h
index 0b63bb81df..400aaa1490 100644
--- a/include/sysemu/kvm_xen.h
+++ b/include/sysemu/kvm_xen.h
@@ -26,6 +26,7 @@ void kvm_xen_inject_vcpu_callback_vector(uint32_t vcpu_id,
int type);
void kvm_xen_set_callback_asserted(void);
int kvm_xen_set_vcpu_virq(uint32_t vcpu_id, uint16_t virq, uint16_t port);
uint16_t kvm_xen_get_gnttab_max_frames(void);
+uint16_t kvm_xen_get_evtchn_max_pirq(void);
#define kvm_xen_has_cap(cap) (!!(kvm_xen_get_caps() & \
KVM_XEN_HVM_CONFIG_ ## cap))
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index b497225fbd..4decd2559b 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -5907,6 +5907,33 @@ static void kvm_arch_set_xen_gnttab_max_frames(Object
*obj, Visitor *v,
s->xen_gnttab_max_frames = value;
}
+static void kvm_arch_get_xen_evtchn_max_pirq(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ KVMState *s = KVM_STATE(obj);
+ uint16_t value = s->xen_evtchn_max_pirq;
+
+ visit_type_uint16(v, name, &value, errp);
+}
+
+static void kvm_arch_set_xen_evtchn_max_pirq(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ KVMState *s = KVM_STATE(obj);
+ Error *error = NULL;
+ uint16_t value;
+
+ visit_type_uint16(v, name, &value, &error);
+ if (error) {
+ error_propagate(errp, error);
+ return;
+ }
+
+ s->xen_evtchn_max_pirq = value;
+}
+
void kvm_arch_accel_class_init(ObjectClass *oc)
{
object_class_property_add_enum(oc, "notify-vmexit", "NotifyVMexitOption",
@@ -5939,6 +5966,13 @@ void kvm_arch_accel_class_init(ObjectClass *oc)
NULL, NULL);
object_class_property_set_description(oc, "xen-gnttab-max-frames",
"Maximum number of grant table
frames");
+
+ object_class_property_add(oc, "xen-evtchn-max-pirq", "uint16",
+ kvm_arch_get_xen_evtchn_max_pirq,
+ kvm_arch_set_xen_evtchn_max_pirq,
+ NULL, NULL);
+ object_class_property_set_description(oc, "xen-evtchn-max-pirq",
+ "Maximum number of Xen PIRQs");
}
void kvm_set_max_apic_id(uint32_t max_apic_id)
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index b3a45ba2fb..2224a06c78 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -1751,6 +1751,12 @@ uint16_t kvm_xen_get_gnttab_max_frames(void)
return s->xen_gnttab_max_frames;
}
+uint16_t kvm_xen_get_evtchn_max_pirq(void)
+{
+ KVMState *s = KVM_STATE(current_accel());
+ return s->xen_evtchn_max_pirq;
+}
+
int kvm_put_xen_state(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
--
2.39.0
