From e4eb4031bddda98414e0a6dd4e0538581c1642c8 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Fri, 16 Feb 2024 22:02:47 -0700
Subject: [PATCH] Fix APIC offsets for x86 32-bit

---
 src/arch/x86_shared/device/ioapic.rs     | 11 +++++++++--
 src/arch/x86_shared/device/local_apic.rs |  8 ++++++--
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/arch/x86_shared/device/ioapic.rs b/src/arch/x86_shared/device/ioapic.rs
index 1123f673bc..e36a83fdbe 100644
--- a/src/arch/x86_shared/device/ioapic.rs
+++ b/src/arch/x86_shared/device/ioapic.rs
@@ -9,7 +9,10 @@ use crate::acpi::madt::{self, Madt, MadtEntry, MadtIntSrcOverride, MadtIoApic};
 use crate::{
     arch::interrupt::irq,
     memory::Frame,
-    paging::{entry::EntryFlags, KernelMapper, Page, PageFlags, PhysicalAddress, RmmA, RmmArch},
+    paging::{
+        entry::EntryFlags, KernelMapper, Page, PageFlags, PhysicalAddress, RmmA, RmmArch,
+        VirtualAddress,
+    },
 };
 
 use super::pic;
@@ -233,7 +236,11 @@ pub unsafe fn handle_ioapic(mapper: &mut KernelMapper, madt_ioapic: &'static Mad
     // map the I/O APIC registers
 
     let frame = Frame::containing_address(PhysicalAddress::new(madt_ioapic.address as usize));
-    let page = Page::containing_address(RmmA::phys_to_virt(frame.start_address()));
+    let page = Page::containing_address(if cfg!(target_arch = "x86") {
+        VirtualAddress::new(crate::IOAPIC_OFFSET)
+    } else {
+        RmmA::phys_to_virt(frame.start_address())
+    });
 
     assert!(mapper.translate(page.start_address()).is_none());
 
diff --git a/src/arch/x86_shared/device/local_apic.rs b/src/arch/x86_shared/device/local_apic.rs
index dc116bd135..60c511a395 100644
--- a/src/arch/x86_shared/device/local_apic.rs
+++ b/src/arch/x86_shared/device/local_apic.rs
@@ -4,7 +4,7 @@ use core::{
 };
 use x86::msr::*;
 
-use crate::paging::{KernelMapper, PageFlags, PhysicalAddress, RmmA, RmmArch};
+use crate::paging::{KernelMapper, PageFlags, PhysicalAddress, RmmA, RmmArch, VirtualAddress};
 
 use crate::arch::cpuid::cpuid;
 
@@ -49,7 +49,11 @@ impl LocalApic {
             .expect("expected KernelMapper not to be locked re-entrant while initializing LAPIC");
 
         let physaddr = PhysicalAddress::new(rdmsr(IA32_APIC_BASE) as usize & 0xFFFF_0000);
-        let virtaddr = RmmA::phys_to_virt(physaddr);
+        let virtaddr = if cfg!(target_arch = "x86") {
+            VirtualAddress::new(crate::LAPIC_OFFSET)
+        } else {
+            RmmA::phys_to_virt(physaddr)
+        };
 
         self.address = virtaddr.data();
         self.x2 = cpuid().map_or(false, |cpuid| {