Re: [edk2-devel] [PATCH 1/1] OvmfPkg PlatformBootManagerLib: Move TryRunningQemuKernel()

["James Bottomley" <James.Bottomley@HansenPartnership.com>]

On Wed, 2021-08-11 at 09:04 +1000, Christoph Willing wrote:
> On 11/8/21 12:26 am, James Bottomley wrote:
> [...]
> > In the working kernel dmesg Gerd requested, what does it mount as
> > root? sda?  In which case what does the kernel say about where it
> > got sda from?
> > 
> Yes it mounts /dev/sda2 as root.
> 
> The boot logs are are now attached at
> https://bugzilla.tianocore.org/show_bug.cgi?id=3504 as well a diff
> between good and bad boots (patched & unpatched code). There's
> nothing obvious (to me) as to why the unpatched code can't find the
> virtual disk.
> 
> My simple minded guess is that PlatformBdsConnectSequence() performs
> some preparatory work that enables the kernel to have access to the
> vm (therefore to the virtual disk) by the time TryRunningQemuKernel()
> is called. At the moment however, TryRunningQemuKernel() is called
> before PlatformBdsConnectSequence() so that preparatory work hasn't
> been done and the disk can't be found.

I suspect the problem is that it no longer creates default devices if
you don't specify them.  If I look at my working version of a command
line boot, it's this:

qemu-kvm \
    -drive if=pflash,format=raw,unit=0,file=/home/jejb/git/edk2/Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd,readonly \
    -debugcon file:debug.log -global isa-debugcon.iobase=0x402 \
    -kernel bzImage \
    -initrd initrd.img \
    -append "console=ttyS0 rd.driver.pre=virtio_scsi,9p,9pnet_virtio root=/dev/sda1" \
    -m 2048 \
    -serial stdio \
    -drive if=none,id=sd00,file=debian.img,format=qcow2 \
    -fsdev local,security_model=passthrough,id=modules,path=/tmp/lib/modules \
    -fsdev local,security_model=passthrough,id=home,path=/home/jejb \
    -device virtio-scsi-pci,id=scsi \
    -device virtio-9p-pci,fsdev=modules,id=sd01,mount_tag=modules \
    -device virtio-9p-pci,fsdev=home,id=sd02,mount_tag=home \
    -device scsi-hd,bus=scsi.0,drive=sd00 \
    -device e1000,netdev=net0 \
    -netdev user,id=net0,hostfwd=tcp::5555-:22 \
    -display vnc=:5 \


#    -chardev socket,id=chrtpm,path=`pwd`/tpmdev/swtpm-sock \
#    -tpmdev emulator,id=tpm0,chardev=chrtpm \
#    -device tpm-tis,tpmdev=tpm0 \

You can ignore all the TPM stuff and my 9p pass throughs for home
directory and /tmp modules directory (to make it easy to boot any
kernel I build).  The relevant lines for you are:

    -drive if=none,id=sd00,file=debian.img,format=qcow2 \
    -device virtio-scsi-pci,id=scsi \
    -device scsi-hd,bus=scsi.0,drive=sd00 \

Which is how I connect /dev/sda to the qcow2 debian image I use to
boot.  You have the drive line but no device lines giving the driver
... if you add device lines can you then get it to boot?

James