[Qemu-devel] [PATCH 1/4] apic: add deliver_msi to APICCommonClass

[Radim Krčmář]

The only way to send interrupts from outside of APIC devices is to use
the MSI-inspired memory mapped interface.  The interface is not
sufficient because interrupt remapping in extended mode can exceed 8 bit
destination ids.

The proper way to deliver interrupts would be to design a bus (QPI), but
that is a big undertaking.  Real IR unit stores excessive bits in the
high work of MSI address register, which would be bit [63:40] in memory
address space, so I was considering two options:
 - a new special address space for APIC to handle MSI-compatible writes
 - one callback to the APIC class that delivers extended MSIs

This patch uses latter option, because it was easier for me, but I think
the former one could be a tad nicer.

Signed-off-by: Radim Krčmář <address@hidden>
---
 hw/i386/kvm/apic.c              | 21 ++++++++++++++-------
 hw/i386/xen/xen_apic.c          |  7 +++++++
 hw/intc/apic.c                  |  7 +++++++
 include/hw/i386/apic_internal.h |  5 +++++
 4 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
index 3c7c8fa00709..7881f13abb96 100644
--- a/hw/i386/kvm/apic.c
+++ b/hw/i386/kvm/apic.c
@@ -147,6 +147,17 @@ static void kvm_apic_external_nmi(APICCommonState *s)
     run_on_cpu(CPU(s->cpu), do_inject_external_nmi, s);
 }
 
+static void kvm_deliver_msi(MSIMessage *msg)
+{
+    int ret;
+
+    ret = kvm_irqchip_send_msi(kvm_state, *msg);
+    if (ret < 0) {
+        fprintf(stderr, "KVM: injection failed, MSI lost (%s)\n",
+                strerror(-ret));
+    }
+}
+
 static uint64_t kvm_apic_mem_read(void *opaque, hwaddr addr,
                                   unsigned size)
 {
@@ -157,13 +168,7 @@ static void kvm_apic_mem_write(void *opaque, hwaddr addr,
                                uint64_t data, unsigned size)
 {
     MSIMessage msg = { .address = addr, .data = data };
-    int ret;
-
-    ret = kvm_irqchip_send_msi(kvm_state, msg);
-    if (ret < 0) {
-        fprintf(stderr, "KVM: injection failed, MSI lost (%s)\n",
-                strerror(-ret));
-    }
+    kvm_deliver_msi(&msg);
 }
 
 static const MemoryRegionOps kvm_apic_io_ops = {
@@ -202,6 +207,8 @@ static void kvm_apic_class_init(ObjectClass *klass, void 
*data)
     k->enable_tpr_reporting = kvm_apic_enable_tpr_reporting;
     k->vapic_base_update = kvm_apic_vapic_base_update;
     k->external_nmi = kvm_apic_external_nmi;
+
+    k->deliver_msi = kvm_deliver_msi;
 }
 
 static const TypeInfo kvm_apic_info = {
diff --git a/hw/i386/xen/xen_apic.c b/hw/i386/xen/xen_apic.c
index 21d68ee04b0a..0f34f63d449d 100644
--- a/hw/i386/xen/xen_apic.c
+++ b/hw/i386/xen/xen_apic.c
@@ -68,6 +68,11 @@ static void xen_apic_external_nmi(APICCommonState *s)
 {
 }
 
+static void xen_deliver_msi(MSIMessage *msi)
+{
+    xen_hvm_inject_msi(msi->address, msi->data);
+}
+
 static void xen_apic_class_init(ObjectClass *klass, void *data)
 {
     APICCommonClass *k = APIC_COMMON_CLASS(klass);
@@ -78,6 +83,8 @@ static void xen_apic_class_init(ObjectClass *klass, void 
*data)
     k->get_tpr = xen_apic_get_tpr;
     k->vapic_base_update = xen_apic_vapic_base_update;
     k->external_nmi = xen_apic_external_nmi;
+
+    k->deliver_msi = xen_deliver_msi;
 }
 
 static const TypeInfo xen_apic_info = {
diff --git a/hw/intc/apic.c b/hw/intc/apic.c
index 28c2ea540608..b893942c6e73 100644
--- a/hw/intc/apic.c
+++ b/hw/intc/apic.c
@@ -877,6 +877,11 @@ static void apic_realize(DeviceState *dev, Error **errp)
     msi_nonbroken = true;
 }
 
+static void apic_deliver_msi(MSIMessage *msi)
+{
+    apic_send_msi(msi->address, msi->data);
+}
+
 static void apic_class_init(ObjectClass *klass, void *data)
 {
     APICCommonClass *k = APIC_COMMON_CLASS(klass);
@@ -889,6 +894,8 @@ static void apic_class_init(ObjectClass *klass, void *data)
     k->external_nmi = apic_external_nmi;
     k->pre_save = apic_pre_save;
     k->post_load = apic_post_load;
+
+    k->deliver_msi = apic_deliver_msi;
 }
 
 static const TypeInfo apic_info = {
diff --git a/include/hw/i386/apic_internal.h b/include/hw/i386/apic_internal.h
index 74fe935e8eab..227ef30c5027 100644
--- a/include/hw/i386/apic_internal.h
+++ b/include/hw/i386/apic_internal.h
@@ -146,6 +146,11 @@ typedef struct APICCommonClass
     void (*pre_save)(APICCommonState *s);
     void (*post_load)(APICCommonState *s);
     void (*reset)(APICCommonState *s);
+
+    /* deliver_msi emulates an APIC bus and its proper place would be in a new
+     * device, but it's convenient to have it here for now.
+     */
+    void (*deliver_msi)(MSIMessage *msi);
 } APICCommonClass;
 
 struct APICCommonState {
-- 
2.8.2