Initial BIOS support.

The --bios argument is added as an alternative to the kernel positional
argument. The BIOS runs in unreal mode (16-bit cs selector set to the
end of 32-bit address space), which matches the default state KVM puts
the segment and data registers into.

Example usage:
Build u-boot with "make qemu-x86_defconfig && make"
Run crosvm with "crosvm_wrapper.sh run --bios=u-boot.rom"

This produces the following message:
"""
U-Boot 2019.01-00017-gdc76aabe6a-dirty (May 21 2019 - 12:17:02 -0700)

CPU:
DRAM:  16 MiB
unable to get online cpu number: -19
Warning: MP init failure
Model: QEMU x86 (I440FX)
Net:   No ethernet found.
error: can't find etc/table-loader
Hit any key to stop autoboot:  0
=>
"""

At this point the u-boot shell works with stdin/stdout, but virtual
disks passed with --rwdisk weren't immediately visible from running
"virtio scan" and "virtio info".

This change puts the bios loading together with the linux kernel loading
code since there is a lot of overlap in functionality.

Bug: b/133358982
Test: ./crosvm_wrapper.sh run --mem=4097 --bios=u-boot.rom
Change-Id: I65b0e1044233af662a642c592d35b106217f3c13
Reviewed-on: https://chromium-review.googlesource.com/1622648
Commit-Ready: Daniel Verkamp <dverkamp@chromium.org>
Tested-by: Daniel Verkamp <dverkamp@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 11 insertions, 8 deletions

diff --git a/aarch64/src/lib.rs b/aarch64/src/lib.rs
index 64dfb1f..4d226c0 100644
--- a/aarch64/src/lib.rs
+++ b/aarch64/src/lib.rs
@@ -11,7 +11,7 @@ use std::io;
 use std::os::unix::io::FromRawFd;
 use std::sync::Arc;
 
-use arch::{RunnableLinuxVm, VmComponents};
+use arch::{RunnableLinuxVm, VmComponents, VmImage};
 use devices::{
     get_serial_tty_string, Bus, BusError, PciConfigMmio, PciDevice, PciInterruptPin,
     SerialParameters,
@@ -124,6 +124,7 @@ pub enum Error {
     CreateVm(sys_util::Error),
     InitrdLoadFailure(arch::LoadImageError),
     KernelLoadFailure(arch::LoadImageError),
+    KernelMissing,
     ReadPreferredTarget(sys_util::Error),
     RegisterIrqfd(sys_util::Error),
     RegisterPci(BusError),
@@ -155,6 +156,7 @@ impl Display for Error {
             CreateVm(e) => write!(f, "failed to create vm: {}", e),
             InitrdLoadFailure(e) => write!(f, "initrd cound not be loaded: {}", e),
             KernelLoadFailure(e) => write!(f, "kernel cound not be loaded: {}", e),
+            KernelMissing => write!(f, "aarch64 requires a kernel"),
             ReadPreferredTarget(e) => write!(f, "failed to read preferred target: {}", e),
             RegisterIrqfd(e) => write!(f, "failed to register irq fd: {}", e),
             RegisterPci(e) => write!(f, "error registering PCI bus: {}", e),
@@ -272,15 +274,16 @@ impl arch::LinuxArch for AArch64 {
             cmdline.insert_str(&param).map_err(Error::Cmdline)?;
         }
 
+        let kernel_image = if let VmImage::Kernel(ref mut img) = components.vm_image {
+            img
+        } else {
+            return Err(Error::KernelMissing);
+        };
+
         // separate out kernel loading from other setup to get a specific error for
         // kernel loading
-        let kernel_size = arch::load_image(
-            &mem,
-            &mut components.kernel_image,
-            get_kernel_addr(),
-            u64::max_value(),
-        )
-        .map_err(Error::KernelLoadFailure)?;
+        let kernel_size = arch::load_image(&mem, kernel_image, get_kernel_addr(), u64::max_value())
+            .map_err(Error::KernelLoadFailure)?;
         let kernel_end = get_kernel_addr().offset() + kernel_size as u64;
         Self::setup_system_memory(
             &mem,