From c45f5c6e2a86085dfcff908376ac7338b0488958 Mon Sep 17 00:00:00 2001
From: Undefine <undefine@undefine.pl>
Date: Sun, 18 Oct 2026 12:59:49 +0200
Subject: [PATCH] Kernel: Disable MSI interrupts when IOAPIC is disabled

MSI interrupts require the IOAPIC to be enabled, trying to run with
`enable_ioapic=off` would cause a kernel panic.
---
 Kernel/Bus/PCI/Device.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Kernel/Bus/PCI/Device.cpp b/Kernel/Bus/PCI/Device.cpp
index e1dd8a5c95a..fc1214a0d55 100644
--- a/Kernel/Bus/PCI/Device.cpp
+++ b/Kernel/Bus/PCI/Device.cpp
@@ -7,6 +7,9 @@
 #include <AK/AnyOf.h>
 #include <Kernel/Arch/Interrupts.h>
 #include <Kernel/Arch/PCIMSI.h>
+#if ARCH(X86_64)
+#    include <Kernel/Arch/x86_64/Interrupts/APIC.h>
+#endif
 #include <Kernel/Bus/PCI/API.h>
 #include <Kernel/Bus/PCI/BarMapping.h>
 #include <Kernel/Bus/PCI/Device.h>
@@ -24,21 +27,33 @@ Device::Device(DeviceIdentifier const& pci_identifier)
 
 bool Device::is_msi_capable() const
 {
+    // FIXME: Move those checks to a better place
     // FIXME: Support MSI on aarch64 and riscv64
 #if ARCH(AARCH64) || ARCH(RISCV64)
     return false;
 #endif
 
+#if ARCH(X86_64)
+    if (!APIC::initialized())
+        return false;
+#endif
+
     return m_pci_identifier->is_msi_capable();
 }
 
 bool Device::is_msix_capable() const
 {
+    // FIXME: Move those checks to a better place
     // FIXME: Support MSIx on aarch64 and riscv64
 #if ARCH(AARCH64) || ARCH(RISCV64)
     return false;
 #endif
 
+#if ARCH(X86_64)
+    if (!APIC::initialized())
+        return false;
+#endif
+
     return m_pci_identifier->is_msix_capable();
 }