mmio: Remove Virtio-over-MMIO support

The code currently does not work and relies on hard-coded addresses.
Removing this code makes the remainder of the code easier to refactor
(by avoiding lifetime complexity). It also makes adding support for
new block devices easier (as we can assume all devices get discovered
via PCI).

Also adds an explicit "Halting.." log, making it clear the firmware is
_intentionally_ hanging.

Signed-off-by: Joe Richey <joerichey@google.com>

Author: josephlr

src/main.rs

@@ -32,7 +32,6 @@ mod efi;
 mod fat;
 mod loader;
 mod mem;
-mod mmio;
 mod part;
 mod pci;
 mod pe;
@@ -182,9 +181,6 @@ pub extern "C" fn rust64_start() -> ! {
         },
     );
 
-    let mut mmio_transport = mmio::VirtioMMIOTransport::new(0xd000_0000u64);
-    let mut device = block::VirtioBlockDevice::new(&mut mmio_transport);
-    boot_from_device(&mut device);
-
+    log!("Unable to boot from any virtio-blk device. Halting..");
     unsafe { halt_loop() }
 }

src/mmio.rs

@@ -14,8 +14,6 @@
 
 /// Virtio related errors
 pub enum Error {
-    VirtioMagicInvalid,
-    VirtioVersionInvalid,
     VirtioUnsupportedDevice,
     VirtioLegacyOnly,
     VirtioFeatureNegotiationFailed,