bootinfo: Add architecture-independent memory entry

`E820Entry` is used in `boot::Info` trait, which is x86_64-dependent
memory entry data structure. It's confusing if e820 is used in other
architectures. This commit introduces an architecture-independent memory
entry `bootinfo::MemoryEntry` and replaces `boot::Info` with
`bootinfo::Info`. This change is suggested in [1].

[1]
cloud-hypervisor#205 (comment)

Signed-off-by: Akira Moroo <retrage01@gmail.com>

src/boot.rs

@@ -1,24 +1,15 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2022 Akira Moroo
+
 use core::mem;
 
 use crate::{
+    bootinfo::{EntryType, Info, MemoryEntry},
     common,
     fat::{Error, Read},
     mem::MemoryRegion,
 };
 
-// Common data needed for all boot paths
-pub trait Info {
-    // Name of for this boot protocol
-    fn name(&self) -> &str;
-    // Starting address of the Root System Descriptor Pointer
-    fn rsdp_addr(&self) -> u64;
-    // The kernel command line (not including null terminator)
-    fn cmdline(&self) -> &[u8];
-    // Methods to access the E820 Memory map
-    fn num_entries(&self) -> u8;
-    fn entry(&self, idx: u8) -> E820Entry;
-}
-
 #[derive(Clone, Copy, Debug)]
 #[repr(C, packed)]
 pub struct E820Entry {
@@ -29,6 +20,61 @@ pub struct E820Entry {
 
 impl E820Entry {
     pub const RAM_TYPE: u32 = 1;
+    pub const RESERVED_TYPE: u32 = 2;
+    pub const ACPI_RECLAIMABLE_TYPE: u32 = 3;
+    pub const ACPI_NVS_TYPE: u32 = 4;
+    pub const BAD_TYPE: u32 = 5;
+    pub const VENDOR_RESERVED_TYPE: u32 = 6; // coreboot only
+    pub const COREBOOT_TABLE_TYPE: u32 = 16; // coreboot only
+}
+
+impl From<u32> for EntryType {
+    fn from(value: u32) -> Self {
+        match value {
+            E820Entry::RAM_TYPE => Self::Ram,
+            E820Entry::RESERVED_TYPE => Self::Reserved,
+            E820Entry::ACPI_RECLAIMABLE_TYPE => Self::AcpiReclaimable,
+            E820Entry::ACPI_NVS_TYPE => Self::AcpiNvs,
+            E820Entry::BAD_TYPE => Self::Bad,
+            E820Entry::VENDOR_RESERVED_TYPE => Self::VendorReserved,
+            E820Entry::COREBOOT_TABLE_TYPE => Self::CorebootTable,
+            _ => panic!("Unsupported e820 type"),
+        }
+    }
+}
+
+impl From<EntryType> for u32 {
+    fn from(value: EntryType) -> Self {
+        match value {
+            EntryType::Ram => E820Entry::RAM_TYPE,
+            EntryType::Reserved => E820Entry::RESERVED_TYPE,
+            EntryType::AcpiReclaimable => E820Entry::ACPI_RECLAIMABLE_TYPE,
+            EntryType::AcpiNvs => E820Entry::ACPI_NVS_TYPE,
+            EntryType::Bad => E820Entry::BAD_TYPE,
+            EntryType::VendorReserved => E820Entry::VENDOR_RESERVED_TYPE,
+            EntryType::CorebootTable => E820Entry::COREBOOT_TABLE_TYPE,
+        }
+    }
+}
+
+impl From<MemoryEntry> for E820Entry {
+    fn from(value: MemoryEntry) -> Self {
+        Self {
+            addr: value.addr,
+            size: value.size,
+            entry_type: u32::from(value.entry_type),
+        }
+    }
+}
+
+impl From<E820Entry> for MemoryEntry {
+    fn from(value: E820Entry) -> Self {
+        Self {
+            addr: value.addr,
+            size: value.size,
+            entry_type: EntryType::from(value.entry_type),
+        }
+    }
 }
 
 // The so-called "zeropage"
@@ -80,9 +126,9 @@ impl Default for Params {
 
 impl Params {
     pub fn set_entries(&mut self, info: &dyn Info) {
-        self.e820_entries = info.num_entries();
+        self.e820_entries = info.num_entries() as u8;
         for i in 0..self.e820_entries {
-            self.e820_table[i as usize] = info.entry(i);
+            self.e820_table[i as usize] = info.entry(i as usize).into();
         }
     }
 }
@@ -97,12 +143,13 @@ impl Info for Params {
     fn cmdline(&self) -> &[u8] {
         unsafe { common::from_cstring(self.hdr.cmd_line_ptr as u64) }
     }
-    fn num_entries(&self) -> u8 {
-        self.e820_entries
+    fn num_entries(&self) -> usize {
+        self.e820_entries as usize
     }
-    fn entry(&self, idx: u8) -> E820Entry {
+    fn entry(&self, idx: usize) -> MemoryEntry {
         assert!(idx < self.num_entries());
-        self.e820_table[idx as usize]
+        let entry = self.e820_table[idx];
+        MemoryEntry::from(entry)
     }
 }
 

src/bootinfo.rs

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2022 Akira Moroo
+
+// Common data needed for all boot paths
+pub trait Info {
+    // Name of for this boot protocol
+    fn name(&self) -> &str;
+    // Starting address of the Root System Descriptor Pointer
+    fn rsdp_addr(&self) -> u64;
+    // The kernel command line (not including null terminator)
+    fn cmdline(&self) -> &[u8];
+    // Methods to access the Memory map
+    fn num_entries(&self) -> usize;
+    fn entry(&self, idx: usize) -> MemoryEntry;
+}
+
+pub struct MemoryEntry {
+    pub addr: u64,
+    pub size: u64,
+    pub entry_type: EntryType,
+}
+
+#[derive(PartialEq)]
+pub enum EntryType {
+    Ram,
+    Reserved,
+    AcpiReclaimable,
+    AcpiNvs,
+    Bad,
+    VendorReserved,
+    CorebootTable,
+}

src/bzimage.rs

@@ -15,7 +15,8 @@ use atomic_refcell::AtomicRefCell;
 
 use crate::{
     block::SectorBuf,
-    boot::{E820Entry, Header, Info, Params},
+    boot::{Header, Params},
+    bootinfo::{EntryType, Info},
     fat::{self, Read},
     mem::MemoryRegion,
 };
@@ -95,7 +96,7 @@ impl Kernel {
         let mut current_addr = None;
         for i in 0..self.0.num_entries() {
             let entry = self.0.entry(i);
-            if entry.entry_type != E820Entry::RAM_TYPE {
+            if entry.entry_type != EntryType::Ram {
                 continue;
             }
 

src/coreboot.rs

@@ -5,7 +5,7 @@
 
 use core::mem::size_of;
 
-use crate::boot::{E820Entry, Info};
+use crate::bootinfo::{EntryType, Info, MemoryEntry};
 
 #[derive(Debug)]
 #[repr(C)]
@@ -38,13 +38,24 @@ struct Forward {
     forward: u64,
 }
 
+#[derive(Clone, Copy)]
 #[repr(packed, C)]
 struct MemMapEntry {
     addr: u64,
     size: u64,
     entry_type: u32,
 }
 
+impl From<MemMapEntry> for MemoryEntry {
+    fn from(value: MemMapEntry) -> Self {
+        Self {
+            addr: value.addr,
+            size: value.size,
+            entry_type: EntryType::from(value.entry_type),
+        }
+    }
+}
+
 #[derive(Debug)]
 #[repr(C)]
 pub struct StartInfo {
@@ -88,21 +99,17 @@ impl Info for StartInfo {
     fn cmdline(&self) -> &[u8] {
         b""
     }
-    fn num_entries(&self) -> u8 {
+    fn num_entries(&self) -> usize {
         if self.memmap_addr == 0 {
             return 0;
         }
-        self.memmap_entries as u8
+        self.memmap_entries
     }
-    fn entry(&self, idx: u8) -> E820Entry {
+    fn entry(&self, idx: usize) -> MemoryEntry {
         assert!(idx < self.num_entries());
         let ptr = self.memmap_addr as *const MemMapEntry;
-        let entry = unsafe { &*ptr.offset(idx as isize) };
-        E820Entry {
-            addr: entry.addr,
-            size: entry.size,
-            entry_type: entry.entry_type,
-        }
+        let entry = unsafe { &*ptr.add(idx) };
+        MemoryEntry::from(*entry)
     }
 }
 

src/efi/mod.rs

@@ -34,7 +34,7 @@ use r_efi::{
     system::{ConfigurationTable, RuntimeServices},
 };
 
-use crate::boot;
+use crate::bootinfo;
 use crate::layout;
 use crate::rtc;
 
@@ -916,16 +916,19 @@ const PAGE_SIZE: u64 = 4096;
 const HEAP_SIZE: usize = 256 * 1024 * 1024;
 
 // Populate allocator from E820, fixed ranges for the firmware and the loaded binary.
-fn populate_allocator(info: &dyn boot::Info, image_address: u64, image_size: u64) {
+fn populate_allocator(info: &dyn bootinfo::Info, image_address: u64, image_size: u64) {
     for i in 0..info.num_entries() {
         let entry = info.entry(i);
-        if entry.entry_type == boot::E820Entry::RAM_TYPE {
-            ALLOCATOR.borrow_mut().add_initial_allocation(
-                efi::CONVENTIONAL_MEMORY,
-                entry.size / PAGE_SIZE,
-                entry.addr,
-                efi::MEMORY_WB,
-            );
+        match entry.entry_type {
+            bootinfo::EntryType::Ram => {
+                ALLOCATOR.borrow_mut().add_initial_allocation(
+                    efi::CONVENTIONAL_MEMORY,
+                    entry.size / PAGE_SIZE,
+                    entry.addr,
+                    efi::MEMORY_WB,
+                );
+            }
+            _ => continue,
         }
     }
 
@@ -1057,7 +1060,7 @@ pub fn efi_exec(
     address: u64,
     loaded_address: u64,
     loaded_size: u64,
-    info: &dyn boot::Info,
+    info: &dyn bootinfo::Info,
     fs: &crate::fat::Filesystem,
     block: *const crate::block::VirtioBlockDevice,
 ) {

src/loader.rs

@@ -14,7 +14,7 @@
 
 use crate::{
     block::SectorBuf,
-    boot,
+    bootinfo,
     bzimage::{self, Kernel},
     common::ascii_strip,
     fat::{self, Read},
@@ -217,7 +217,10 @@ fn default_entry_path(fs: &fat::Filesystem) -> Result<[u8; 260], Error> {
     Ok(entry_path)
 }
 
-pub fn load_default_entry(fs: &fat::Filesystem, info: &dyn boot::Info) -> Result<Kernel, Error> {
+pub fn load_default_entry(
+    fs: &fat::Filesystem,
+    info: &dyn bootinfo::Info,
+) -> Result<Kernel, Error> {
     let default_entry_path = default_entry_path(fs)?;
     let default_entry_path = ascii_strip(&default_entry_path);
 

src/main.rs

@@ -35,6 +35,7 @@ mod common;
 mod arch;
 mod block;
 mod boot;
+mod bootinfo;
 mod bzimage;
 #[cfg(target_arch = "x86_64")]
 mod cmos;
@@ -75,7 +76,7 @@ fn panic(_: &PanicInfo) -> ! {
 const VIRTIO_PCI_VENDOR_ID: u16 = 0x1af4;
 const VIRTIO_PCI_BLOCK_DEVICE_ID: u16 = 0x1042;
 
-fn boot_from_device(device: &mut block::VirtioBlockDevice, info: &dyn boot::Info) -> bool {
+fn boot_from_device(device: &mut block::VirtioBlockDevice, info: &dyn bootinfo::Info) -> bool {
     if let Err(err) = device.init() {
         log!("Error configuring block device: {:?}", err);
         return false;
@@ -153,7 +154,7 @@ pub extern "C" fn rust64_start(#[cfg(not(feature = "coreboot"))] pvh_info: &pvh:
 }
 
 #[cfg(target_arch = "x86_64")]
-fn main(info: &dyn boot::Info) -> ! {
+fn main(info: &dyn bootinfo::Info) -> ! {
     log!("\nBooting with {}", info.name());
 
     pci::print_bus();

src/pvh.rs

@@ -1,7 +1,7 @@
 use core::mem::size_of;
 
 use crate::{
-    boot::{E820Entry, Info},
+    bootinfo::{EntryType, Info, MemoryEntry},
     common,
 };
 
@@ -30,6 +30,16 @@ struct MemMapEntry {
     _pad: u32,
 }
 
+impl From<MemMapEntry> for MemoryEntry {
+    fn from(value: MemMapEntry) -> Self {
+        Self {
+            addr: value.addr,
+            size: value.size,
+            entry_type: EntryType::from(value.entry_type),
+        }
+    }
+}
+
 impl Info for StartInfo {
     fn name(&self) -> &str {
         "PVH Boot Protocol"
@@ -40,22 +50,18 @@ impl Info for StartInfo {
     fn cmdline(&self) -> &[u8] {
         unsafe { common::from_cstring(self.cmdline_paddr) }
     }
-    fn num_entries(&self) -> u8 {
+    fn num_entries(&self) -> usize {
         // memmap_paddr and memmap_entries only exist in version 1 or later
         if self.version < 1 || self.memmap_paddr == 0 {
             return 0;
         }
-        self.memmap_entries as u8
+        self.memmap_entries as usize
     }
-    fn entry(&self, idx: u8) -> E820Entry {
+    fn entry(&self, idx: usize) -> MemoryEntry {
         assert!(idx < self.num_entries());
         let ptr = self.memmap_paddr as *const MemMapEntry;
-        let entry = unsafe { *ptr.offset(idx as isize) };
-        E820Entry {
-            addr: entry.addr,
-            size: entry.size,
-            entry_type: entry.entry_type,
-        }
+        let entry = unsafe { *ptr.add(idx) };
+        MemoryEntry::from(entry)
     }
 }