hw/intc: Generalize APIC helper names from kvm_* to accel_*

Rename APIC helper functions to use an accel_* prefix instead of kvm_*
to support use by accelerators other than KVM. This is a preparatory
step for integrating MSHV support with common APIC logic.

Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250916164847.77883-5-magnuskulke@linux.microsoft.com
[Remove dead definition of mshv_msi_via_irqfd_enabled. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

accel/accel-irq.c

@@ -0,0 +1,106 @@
+/*
+ * Accelerated irqchip abstraction
+ *
+ * Copyright Microsoft, Corp. 2025
+ *
+ * Authors: Ziqiao Zhou <ziqiaozhou@microsoft.com>
+ *          Magnus Kulke <magnuskulke@microsoft.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/pci/msi.h"
+
+#include "system/kvm.h"
+#include "system/mshv.h"
+#include "system/accel-irq.h"
+
+int accel_irqchip_add_msi_route(KVMRouteChange *c, int vector, PCIDevice *dev)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        return mshv_irqchip_add_msi_route(vector, dev);
+    }
+#endif
+    if (kvm_enabled()) {
+        return kvm_irqchip_add_msi_route(c, vector, dev);
+    }
+    return -ENOSYS;
+}
+
+int accel_irqchip_update_msi_route(int vector, MSIMessage msg, PCIDevice *dev)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        return mshv_irqchip_update_msi_route(vector, msg, dev);
+    }
+#endif
+    if (kvm_enabled()) {
+        return kvm_irqchip_update_msi_route(kvm_state, vector, msg, dev);
+    }
+    return -ENOSYS;
+}
+
+void accel_irqchip_commit_route_changes(KVMRouteChange *c)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        mshv_irqchip_commit_routes();
+    }
+#endif
+    if (kvm_enabled()) {
+        kvm_irqchip_commit_route_changes(c);
+    }
+}
+
+void accel_irqchip_commit_routes(void)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        mshv_irqchip_commit_routes();
+    }
+#endif
+    if (kvm_enabled()) {
+        kvm_irqchip_commit_routes(kvm_state);
+    }
+}
+
+void accel_irqchip_release_virq(int virq)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        mshv_irqchip_release_virq(virq);
+    }
+#endif
+    if (kvm_enabled()) {
+        kvm_irqchip_release_virq(kvm_state, virq);
+    }
+}
+
+int accel_irqchip_add_irqfd_notifier_gsi(EventNotifier *n, EventNotifier *rn,
+                                         int virq)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        return mshv_irqchip_add_irqfd_notifier_gsi(n, rn, virq);
+    }
+#endif
+    if (kvm_enabled()) {
+        return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, rn, virq);
+    }
+    return -ENOSYS;
+}
+
+int accel_irqchip_remove_irqfd_notifier_gsi(EventNotifier *n, int virq)
+{
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+    if (mshv_msi_via_irqfd_enabled()) {
+        return mshv_irqchip_remove_irqfd_notifier_gsi(n, virq);
+    }
+#endif
+    if (kvm_enabled()) {
+        return kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, virq);
+    }
+    return -ENOSYS;
+}

accel/meson.build

@@ -1,6 +1,6 @@
 common_ss.add(files('accel-common.c'))
 specific_ss.add(files('accel-target.c'))
-system_ss.add(files('accel-system.c', 'accel-blocker.c', 'accel-qmp.c'))
+system_ss.add(files('accel-system.c', 'accel-blocker.c', 'accel-qmp.c', 'accel-irq.c'))
 user_ss.add(files('accel-user.c'))
 
 subdir('tcg')

hw/intc/ioapic.c

@@ -30,12 +30,18 @@
 #include "hw/intc/ioapic_internal.h"
 #include "hw/pci/msi.h"
 #include "hw/qdev-properties.h"
+#include "system/accel-irq.h"
 #include "system/kvm.h"
 #include "system/system.h"
 #include "hw/i386/apic-msidef.h"
 #include "hw/i386/x86-iommu.h"
 #include "trace.h"
 
+
+#if defined(CONFIG_KVM) || defined(CONFIG_MSHV)
+#define ACCEL_GSI_IRQFD_POSSIBLE
+#endif
+
 #define APIC_DELIVERY_MODE_SHIFT 8
 #define APIC_POLARITY_SHIFT 14
 #define APIC_TRIG_MODE_SHIFT 15
@@ -191,10 +197,10 @@ static void ioapic_set_irq(void *opaque, int vector, int level)
 
 static void ioapic_update_kvm_routes(IOAPICCommonState *s)
 {
-#ifdef CONFIG_KVM
+#ifdef ACCEL_GSI_IRQFD_POSSIBLE
     int i;
 
-    if (kvm_irqchip_is_split()) {
+    if (accel_irqchip_is_split()) {
         for (i = 0; i < IOAPIC_NUM_PINS; i++) {
             MSIMessage msg;
             struct ioapic_entry_info info;
@@ -202,15 +208,15 @@ static void ioapic_update_kvm_routes(IOAPICCommonState *s)
             if (!info.masked) {
                 msg.address = info.addr;
                 msg.data = info.data;
-                kvm_irqchip_update_msi_route(kvm_state, i, msg, NULL);
+                accel_irqchip_update_msi_route(i, msg, NULL);
             }
         }
-        kvm_irqchip_commit_routes(kvm_state);
+        accel_irqchip_commit_routes();
     }
 #endif
 }
 
-#ifdef CONFIG_KVM
+#ifdef ACCEL_KERNEL_GSI_IRQFD_POSSIBLE
 static void ioapic_iec_notifier(void *private, bool global,
                                 uint32_t index, uint32_t mask)
 {
@@ -428,11 +434,11 @@ static const MemoryRegionOps ioapic_io_ops = {
 
 static void ioapic_machine_done_notify(Notifier *notifier, void *data)
 {
-#ifdef CONFIG_KVM
+#ifdef ACCEL_KERNEL_GSI_IRQFD_POSSIBLE
     IOAPICCommonState *s = container_of(notifier, IOAPICCommonState,
                                         machine_done);
 
-    if (kvm_irqchip_is_split()) {
+    if (accel_irqchip_is_split()) {
         X86IOMMUState *iommu = x86_iommu_get_default();
         if (iommu) {
             /* Register this IOAPIC with IOMMU IEC notifier, so that

hw/virtio/virtio-pci.c

@@ -34,6 +34,7 @@
 #include "hw/pci/msi.h"
 #include "hw/pci/msix.h"
 #include "hw/loader.h"
+#include "system/accel-irq.h"
 #include "system/kvm.h"
 #include "hw/virtio/virtio-pci.h"
 #include "qemu/range.h"
@@ -825,11 +826,11 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
 
     if (irqfd->users == 0) {
         KVMRouteChange c = kvm_irqchip_begin_route_changes(kvm_state);
-        ret = kvm_irqchip_add_msi_route(&c, vector, &proxy->pci_dev);
+        ret = accel_irqchip_add_msi_route(&c, vector, &proxy->pci_dev);
         if (ret < 0) {
             return ret;
         }
-        kvm_irqchip_commit_route_changes(&c);
+        accel_irqchip_commit_route_changes(&c);
         irqfd->virq = ret;
     }
     irqfd->users++;
@@ -841,7 +842,7 @@ static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
 {
     VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
     if (--irqfd->users == 0) {
-        kvm_irqchip_release_virq(kvm_state, irqfd->virq);
+        accel_irqchip_release_virq(irqfd->virq);
     }
 }
 
@@ -850,7 +851,7 @@ static int kvm_virtio_pci_irqfd_use(VirtIOPCIProxy *proxy,
                                  unsigned int vector)
 {
     VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
-    return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, irqfd->virq);
+    return accel_irqchip_add_irqfd_notifier_gsi(n, NULL, irqfd->virq);
 }
 
 static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy *proxy,
@@ -860,7 +861,7 @@ static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy *proxy,
     VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
     int ret;
 
-    ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, irqfd->virq);
+    ret = accel_irqchip_remove_irqfd_notifier_gsi(n, irqfd->virq);
     assert(ret == 0);
 }
 static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, int queue_no,
@@ -995,12 +996,12 @@ static int virtio_pci_one_vector_unmask(VirtIOPCIProxy *proxy,
     if (proxy->vector_irqfd) {
         irqfd = &proxy->vector_irqfd[vector];
         if (irqfd->msg.data != msg.data || irqfd->msg.address != msg.address) {
-            ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq, msg,
-                                               &proxy->pci_dev);
+            ret = accel_irqchip_update_msi_route(irqfd->virq, msg,
+                                                 &proxy->pci_dev);
             if (ret < 0) {
                 return ret;
             }
-            kvm_irqchip_commit_routes(kvm_state);
+            accel_irqchip_commit_routes();
         }
     }
 
@@ -1229,7 +1230,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
     int r, n;
     bool with_irqfd = msix_enabled(&proxy->pci_dev) &&
-        kvm_msi_via_irqfd_enabled();
+        accel_msi_via_irqfd_enabled() ;
 
     nvqs = MIN(nvqs, VIRTIO_QUEUE_MAX);
 
@@ -1433,7 +1434,7 @@ static void virtio_pci_set_vector(VirtIODevice *vdev,
                                   uint16_t new_vector)
 {
     bool kvm_irqfd = (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) &&
-        msix_enabled(&proxy->pci_dev) && kvm_msi_via_irqfd_enabled();
+        msix_enabled(&proxy->pci_dev) && accel_msi_via_irqfd_enabled();
 
     if (new_vector == old_vector) {
         return;

include/system/accel-irq.h

@@ -0,0 +1,37 @@
+/*
+ * Accelerated irqchip abstraction
+ *
+ * Copyright Microsoft, Corp. 2025
+ *
+ * Authors: Ziqiao Zhou <ziqiaozhou@microsoft.com>
+ *          Magnus Kulke <magnuskulke@microsoft.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef SYSTEM_ACCEL_IRQ_H
+#define SYSTEM_ACCEL_IRQ_H
+#include "hw/pci/msi.h"
+#include "qemu/osdep.h"
+#include "system/kvm.h"
+#include "system/mshv.h"
+
+static inline bool accel_msi_via_irqfd_enabled(void)
+{
+    return mshv_msi_via_irqfd_enabled() || kvm_msi_via_irqfd_enabled();
+}
+
+static inline bool accel_irqchip_is_split(void)
+{
+    return mshv_msi_via_irqfd_enabled() || kvm_irqchip_is_split();
+}
+
+int accel_irqchip_add_msi_route(KVMRouteChange *c, int vector, PCIDevice *dev);
+int accel_irqchip_update_msi_route(int vector, MSIMessage msg, PCIDevice *dev);
+void accel_irqchip_commit_route_changes(KVMRouteChange *c);
+void accel_irqchip_commit_routes(void);
+void accel_irqchip_release_virq(int virq);
+int accel_irqchip_add_irqfd_notifier_gsi(EventNotifier *n, EventNotifier *rn,
+                                         int virq);
+int accel_irqchip_remove_irqfd_notifier_gsi(EventNotifier *n, int virq);
+#endif

include/system/mshv.h

@@ -22,4 +22,21 @@
 #define CONFIG_MSHV_IS_POSSIBLE
 #endif
 
+#ifdef CONFIG_MSHV_IS_POSSIBLE
+extern bool mshv_allowed;
+#define mshv_enabled() (mshv_allowed)
+#else /* CONFIG_MSHV_IS_POSSIBLE */
+#define mshv_enabled() false
+#endif
+#define mshv_msi_via_irqfd_enabled() false
+
+/* interrupt */
+int mshv_irqchip_add_msi_route(int vector, PCIDevice *dev);
+int mshv_irqchip_update_msi_route(int virq, MSIMessage msg, PCIDevice *dev);
+void mshv_irqchip_commit_routes(void);
+void mshv_irqchip_release_virq(int virq);
+int mshv_irqchip_add_irqfd_notifier_gsi(const EventNotifier *n,
+                                        const EventNotifier *rn, int virq);
+int mshv_irqchip_remove_irqfd_notifier_gsi(const EventNotifier *n, int virq);
+
 #endif