[RFC,v4,2/5] hw/arm: Allow setting KVM vGIC maintenance IRQ

Commit Message

Eric Auger Jan. 16, 2025, 8:32 a.m. UTC

From: Haibo Xu <[e-mail]>

Allow virt arm machine to set the interrupt ID for the KVM
GIC maintenance interrupt.

This setting must be done before the KVM_DEV_ARM_VGIC_CTRL_INIT
hence the choice to perform the setting in the GICv3 realize
instead of proceeding the same way as kvm_arm_pmu_set_irq().

Signed-off-by: Haibo Xu <[e-mail]>
Signed-off-by: Miguel Luis <[e-mail]>
Signed-off-by: Eric Auger <[e-mail]>

---

v3 -> v4:
- only set maint_irq if vms->virt

v2 -> v3:
- tweak the commit message and explain why we do not proceed
  the same way as kvm_arm_pmu_set_irq (Peter)

v1 -> v2:
- [Miguel] replaced the has_virt_extensions by the maintenance irq
  intid property. [Eric] restored kvm_device_check_attr and
  kvm_device_access standard usage and conditionally call those
  if the prop is set.
---
 include/hw/intc/arm_gicv3_common.h |  1 +
 hw/arm/virt.c                      |  3 +++
 hw/intc/arm_gicv3_common.c         |  1 +
 hw/intc/arm_gicv3_kvm.c            | 21 +++++++++++++++++++++
 4 files changed, 26 insertions(+)

Patch

diff --git a/include/hw/intc/arm_gicv3_common.h b/include/hw/intc/arm_gicv3_common.h
index a3d6a0e507..c18503869f 100644
--- a/include/hw/intc/arm_gicv3_common.h
+++ b/include/hw/intc/arm_gicv3_common.h
@@ -231,6 +231,7 @@  struct GICv3State {
     uint32_t num_cpu;
     uint32_t num_irq;
     uint32_t revision;
+    uint32_t maint_irq;
     bool lpi_enable;
     bool nmi_support;
     bool security_extn;
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 99e0a68b6c..55b0bb24ba 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -827,6 +827,9 @@  static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
                                          OBJECT(mem), &error_fatal);
                 qdev_prop_set_bit(vms->gic, "has-lpi", true);
             }
+        } else if (vms->virt) {
+            qdev_prop_set_uint32(vms->gic, "maintenance-interrupt-id",
+                                 ARCH_GIC_MAINT_IRQ);
         }
     } else {
         if (!kvm_irqchip_in_kernel()) {
diff --git a/hw/intc/arm_gicv3_common.c b/hw/intc/arm_gicv3_common.c
index 76b2283c92..2ed50d7d07 100644
--- a/hw/intc/arm_gicv3_common.c
+++ b/hw/intc/arm_gicv3_common.c
@@ -612,6 +612,7 @@  static const Property arm_gicv3_common_properties[] = {
     DEFINE_PROP_BOOL("has-lpi", GICv3State, lpi_enable, 0),
     DEFINE_PROP_BOOL("has-nmi", GICv3State, nmi_support, 0),
     DEFINE_PROP_BOOL("has-security-extensions", GICv3State, security_extn, 0),
+    DEFINE_PROP_UINT32("maintenance-interrupt-id", GICv3State, maint_irq, 0),
     /*
      * Compatibility property: force 8 bits of physical priority, even
      * if the CPU being emulated should have fewer.
diff --git a/hw/intc/arm_gicv3_kvm.c b/hw/intc/arm_gicv3_kvm.c
index 8e17cab2a0..7248055a02 100644
--- a/hw/intc/arm_gicv3_kvm.c
+++ b/hw/intc/arm_gicv3_kvm.c
@@ -22,6 +22,7 @@ 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "hw/intc/arm_gicv3_common.h"
+#include "hw/arm/virt.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "system/kvm.h"
@@ -825,6 +826,26 @@  static void kvm_arm_gicv3_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (s->maint_irq) {
+        int ret;
+
+        ret = kvm_device_check_attr(s->dev_fd,
+                                    KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ, 0);
+        if (!ret) {
+            error_setg_errno(errp, errno,
+                             "VGICv3 setting maintenance IRQ is not "
+                             "supported by this host kernel");
+            return;
+        }
+
+        ret = kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_MAINT_IRQ, 0,
+                                &s->maint_irq, true, errp);
+        if (ret) {
+            error_setg_errno(errp, errno, "Failed to set VGIC maintenance IRQ");
+            return;
+       }
+    }
+
     multiple_redist_region_allowed =
         kvm_device_check_attr(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
                               KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION);