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Implement an efficient ranged page table

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This commit is contained in:
Zhang Junyang
2024-03-25 13:25:32 +08:00
committed by Tate, Hongliang Tian
parent c9cfb98746
commit 24a868a670
25 changed files with 1540 additions and 964 deletions
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39
framework/aster-frame/src/trap/handler.rs
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@ -2,6 +2,7 @@
use core::sync::atomic::{AtomicBool, Ordering};
use align_ext::AlignExt;
use log::debug;
#[cfg(feature = "intel_tdx")]
use tdx_guest::tdcall;
@ -15,13 +16,14 @@ use crate::arch::{
tdx_guest::{handle_virtual_exception, TdxTrapFrame},
};
use crate::{
arch::{
irq::IRQ_LIST,
mm::{PageTableEntry, PageTableFlags},
},
arch::irq::IRQ_LIST,
cpu::{CpuException, PageFaultErrorCode, PAGE_FAULT},
cpu_local,
vm::{PageTable, PHYS_MEM_BASE_VADDR, PHYS_MEM_VADDR_RANGE},
vm::{
kspace::{KERNEL_PAGE_TABLE, LINEAR_MAPPING_BASE_VADDR},
page_table::{CachePolicy, MapProperty},
VmPerm, PAGE_SIZE, PHYS_MEM_VADDR_RANGE,
},
};
#[cfg(feature = "intel_tdx")]
@ -180,6 +182,8 @@ pub fn in_interrupt_context() -> bool {
IN_INTERRUPT_CONTEXT.load(Ordering::Acquire)
}
/// FIXME: this is a hack because we don't allocate kernel space for IO memory. We are currently
/// using the linear mapping for IO memory. This is not a good practice.
fn handle_kernel_page_fault(f: &TrapFrame) {
let page_fault_vaddr = x86_64::registers::control::Cr2::read().as_u64();
let error_code = PageFaultErrorCode::from_bits_truncate(f.error_code);
@ -210,21 +214,28 @@ fn handle_kernel_page_fault(f: &TrapFrame) {
"kernel page fault: the direct mapping already exists",
);
// FIXME: Is it safe to call `PageTable::from_root_register` here?
let mut page_table: PageTable<PageTableEntry, crate::vm::page_table::KernelMode> =
unsafe { PageTable::from_root_register() };
let paddr = page_fault_vaddr as usize - PHYS_MEM_BASE_VADDR;
let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
// Do the mapping
let mut page_table = KERNEL_PAGE_TABLE
.get()
.expect("The kernel page table is not initialized when kernel page fault happens")
.lock();
let vaddr = (page_fault_vaddr as usize).align_down(PAGE_SIZE);
let paddr = vaddr - LINEAR_MAPPING_BASE_VADDR;
// SAFETY:
// 1. We have checked that the page fault address falls within the address range of the direct
// mapping of physical memory.
// 2. We map the address to the correct physical page with the correct flags, where the
// correctness follows the semantics of the direct mapping of physical memory.
// Do the mapping
unsafe {
page_table
.map(page_fault_vaddr as usize, paddr, flags)
.unwrap();
page_table.map_unchecked(
&(vaddr..vaddr + PAGE_SIZE),
&(paddr..paddr + PAGE_SIZE),
MapProperty {
perm: VmPerm::RW | VmPerm::G,
cache: CachePolicy::Uncacheable,
},
)
}
}