Merge pull request #102 from cryptoknight/77-add-page-size-constant

Replace magic page size numbers with constants

Author: ALSchwalm

.gitignore

@@ -1,8 +1,9 @@
 /boot
 /target
-mythril/target
-mythril/src/blob/bios.bin
 mythril/.cargo
+mythril/src/blob/bios.bin
+mythril/target
+mythril/vendor
 _boot.img
 **/*.rs.bk
 debug.log

mythril/src/memory.rs

@@ -14,10 +14,10 @@ use x86::bits64::paging::*;
 use x86::controlregs::Cr0;
 
 #[repr(align(4096))]
-pub struct Raw4kPage(pub [u8; 4096]);
+pub struct Raw4kPage(pub [u8; BASE_PAGE_SIZE]);
 impl Default for Raw4kPage {
     fn default() -> Self {
-        Raw4kPage([0u8; 4096])
+        Raw4kPage([0u8; BASE_PAGE_SIZE])
     }
 }
 
@@ -221,7 +221,7 @@ impl fmt::Debug for HostPhysAddr {
 #[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
 pub struct HostPhysFrame(HostPhysAddr);
 impl HostPhysFrame {
-    pub const SIZE: usize = 4096;
+    pub const SIZE: usize = BASE_PAGE_SIZE;
 
     pub fn from_start_address(addr: HostPhysAddr) -> Result<Self> {
         if !addr.is_frame_aligned() {
@@ -391,7 +391,7 @@ impl GuestAddressSpace {
         addr: GuestVirtAddr,
         access: GuestAccess,
     ) -> Result<FrameIter> {
-        //TODO: align the addr to 4096 boundary
+        //TODO: align the addr to BASE_PAGE_SIZE boundary
         Ok(FrameIter {
             view: GuestAddressSpaceView::new(cr3, self),
             addr: addr,
@@ -561,7 +561,7 @@ impl<'a> Iterator for FrameIter<'a> {
 
         // This is the smallest possible guest page size, so permissions
         // can't change except at this granularity
-        self.addr = self.addr + 4096;
+        self.addr = self.addr + BASE_PAGE_SIZE;
 
         let physaddr =
             match self.view.translate_linear_address(old, self.access) {
@@ -574,15 +574,15 @@ impl<'a> Iterator for FrameIter<'a> {
 
 #[repr(align(4096))]
 pub struct EptTable<T> {
-    entries: [T; 512],
+    entries: [T; PAGE_SIZE_ENTRIES],
 }
 impl<T> Default for EptTable<T>
 where
     T: Copy + Default,
 {
     fn default() -> Self {
         Self {
-            entries: [T::default(); 512],
+            entries: [T::default(); PAGE_SIZE_ENTRIES],
         }
     }
 }

mythril/src/vm.rs

@@ -19,6 +19,7 @@ use alloc::string::String;
 use alloc::sync::Arc;
 use alloc::vec::Vec;
 use arraydeque::ArrayDeque;
+use core::mem;
 use spin::RwLock;
 
 static BIOS_BLOB: &'static [u8] = include_bytes!("blob/bios.bin");
@@ -345,7 +346,8 @@ impl VirtualMachine {
         addr: &GuestPhysAddr,
         space: &mut GuestAddressSpace,
     ) -> Result<()> {
-        for (i, chunk) in image.chunks(4096 as usize).enumerate() {
+        for (i, chunk) in image.chunks(mem::size_of::<Raw4kPage>()).enumerate()
+        {
             let frame_ptr =
                 Box::into_raw(Box::new(Raw4kPage::default())) as *mut u8;
             let frame = HostPhysFrame::from_start_address(HostPhysAddr::new(
@@ -362,7 +364,8 @@ impl VirtualMachine {
 
             space.map_frame(
                 memory::GuestPhysAddr::new(
-                    addr.as_u64() + (i as u64 * 4096) as u64,
+                    addr.as_u64()
+                        + (i as u64 * mem::size_of::<Raw4kPage>() as u64),
                 ),
                 frame,
                 false,
@@ -417,7 +420,9 @@ impl VirtualMachine {
         // Iterate over each page
         for i in 0..(config.memory << 8) {
             match guest_space.map_new_frame(
-                memory::GuestPhysAddr::new((i as u64 * 4096) as u64),
+                memory::GuestPhysAddr::new(
+                    i as u64 * mem::size_of::<Raw4kPage>() as u64,
+                ),
                 false,
             ) {
                 Ok(_) | Err(Error::DuplicateMapping(_)) => continue,