diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
index e92f236bf4..5e4182b474 100644
--- a/hw/i386/microvm.c
+++ b/hw/i386/microvm.c
@@ -181,6 +181,7 @@ static void microvm_devices_init(MicrovmMachineState *mms)
     mms->virtio_irq_base = 5;
     mms->virtio_num_transports = 8;
     if (x86_machine_is_acpi_enabled(x86ms)) {
+        mms->pcie_irq_base = 12;
         mms->virtio_irq_base = 16;
     }
 
@@ -226,12 +227,12 @@ static void microvm_devices_init(MicrovmMachineState *mms)
         mms->gpex.mmio32.size = PCIE_MMIO_SIZE;
         mms->gpex.ecam.base   = PCIE_ECAM_BASE;
         mms->gpex.ecam.size   = PCIE_ECAM_SIZE;
-        mms->gpex.irq         = PCIE_IRQ_BASE;
+        mms->gpex.irq         = mms->pcie_irq_base;
         create_gpex(mms);
-        x86ms->pci_irq_mask = ((1 << (PCIE_IRQ_BASE + 0)) |
-                               (1 << (PCIE_IRQ_BASE + 1)) |
-                               (1 << (PCIE_IRQ_BASE + 2)) |
-                               (1 << (PCIE_IRQ_BASE + 3)));
+        x86ms->pci_irq_mask = ((1 << (mms->pcie_irq_base + 0)) |
+                               (1 << (mms->pcie_irq_base + 1)) |
+                               (1 << (mms->pcie_irq_base + 2)) |
+                               (1 << (mms->pcie_irq_base + 3)));
     } else {
         x86ms->pci_irq_mask = 0;
     }
diff --git a/include/hw/i386/microvm.h b/include/hw/i386/microvm.h
index c5d60bacb5..f1e9db059b 100644
--- a/include/hw/i386/microvm.h
+++ b/include/hw/i386/microvm.h
@@ -66,7 +66,6 @@
 #define PCIE_MMIO_SIZE        0x20000000
 #define PCIE_ECAM_BASE        0xe0000000
 #define PCIE_ECAM_SIZE        0x10000000
-#define PCIE_IRQ_BASE         12
 
 /* Machine type options */
 #define MICROVM_MACHINE_PIT                 "pit"
@@ -96,6 +95,7 @@ struct MicrovmMachineState {
     bool auto_kernel_cmdline;
 
     /* Machine state */
+    uint32_t pcie_irq_base;
     uint32_t virtio_irq_base;
     uint32_t virtio_num_transports;
     bool kernel_cmdline_fixed;