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acpi_protect: Fix unaligned memory access #20

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Merged
PG-MANA merged 1 commit into from
Sep 8, 2025
Merged

acpi_protect: Fix unaligned memory access #20

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14 changes: 9 additions & 5 deletions src/hypervisor_kernel/src/acpi_protect.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@ use crate::memory_hook::{
};
use crate::paging::add_memory_access_trap;

use core::ptr::read_unaligned;

const EXCEPT_TABLE: [&[u8; 4]; 0] = [];

pub fn init_table_protection(rsdp_address: usize) {
Expand All @@ -30,7 +32,9 @@ pub fn init_table_protection(rsdp_address: usize) {

'table_loop: for table_index in 0..((xsdt.length as usize - XSDT_STRUCT_SIZE) >> 3) {
let table_address = unsafe {
*((xsdt as *const _ as usize + XSDT_STRUCT_SIZE + (table_index << 3)) as *const u64)
read_unaligned(
(xsdt as *const _ as usize + XSDT_STRUCT_SIZE + (table_index << 3)) as *const u64,
)
} as usize;
let signature = unsafe { &*(table_address as *const [u8; 4]) };

Expand All @@ -47,12 +51,12 @@ pub fn init_table_protection(rsdp_address: usize) {
}
} else if *signature == *b"FACP" && !is_dsdt_processed {
register_acpi_table(table_address, None);
let x_dsdt_address = unsafe { *((table_address + 140) as *const u64) };
let x_dsdt_address = unsafe { read_unaligned((table_address + 140) as *const u64) };
if x_dsdt_address != 0 {
register_acpi_table(x_dsdt_address as usize, None);
is_dsdt_processed = true;
} else {
let dsdt_address = unsafe { *((table_address + 40) as *const u32) };
let dsdt_address = unsafe { read_unaligned((table_address + 40) as *const u32) };
if dsdt_address != 0 {
register_acpi_table(dsdt_address as usize, None);
is_dsdt_processed = true;
Expand All @@ -65,8 +69,8 @@ pub fn init_table_protection(rsdp_address: usize) {
}

fn register_acpi_table(table_address: usize, table_length: Option<u32>) {
let table_length =
table_length.unwrap_or_else(|| unsafe { *((table_address + 4) as *const u32) });
let table_length = table_length
.unwrap_or_else(|| unsafe { read_unaligned((table_address + 4) as *const u32) });
let aligned_table_address = table_address & STAGE_2_PAGE_MASK;
let aligned_table_length =
(((table_length as usize) + (table_address - aligned_table_address) - 1)
Expand Down