From e16aff4cc2ef285d1346abcff1a1752614fa9c60 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 18 Jan 2023 14:36:23 +0000 Subject: [PATCH] kvm/i386: Add xen-evtchn-max-pirq property 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 Reviewed-by: Paul Durrant --- 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 3d8e400bbf..f2a6ea6a68 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 69c0204d4f..886fbf6b3b 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 b2aafaf7ab..595abfbe40 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 d390137f02..1aef54f87e 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -5922,6 +5922,33 @@ 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", @@ -5954,6 +5981,13 @@ 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 96a9082196..bad3131d08 100644 --- a/target/i386/kvm/xen-emu.c +++ b/target/i386/kvm/xen-emu.c @@ -1765,6 +1765,12 @@ 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);