Message-ID: <dbef7b89aa65887bda1a59dc37602385416828b5.camel@xry111.site>
Subject: PAE + virtio = probe error?
From:   Xi Ruoyao <xry111@xry111.site>
To:     virtualization@lists.linux-foundation.org
Cc:     linux-kernel@vger.kernel.org
Date:   Thu, 09 Mar 2023 22:50:21 +0800
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Hello,

I'm using a QEMU VM for testing things on 32-bit x86.  Today I updated
the VM to use Linux kernel 6.2.2, and a strange issue happened: both
virtio block driver and virtio network driver fail to probe with errors
like:

[    0.950474] virtio_blk virtio1: virtio: device uses modern interface but=
 does not have VIRTIO_F_VERSION_1
[    0.951669] virtio_blk: probe of virtio1 failed with error -22

I spent some time debugging the issue, and it turned out if I disable
CONFIG_X86_PAE, the virtio drivers would function normally.  But then I
can only use 4GB RAM in the VM.

Is this a bug or I'm doing something wrong?  The command to start the VM
is:

qemu -enable-kvm                     \
     -smp 8                          \
     -cpu host                       \
     -m 16G                          \
     -drive file=3Ddisk.img,if=3Dvirtio  \
     -boot menu=3Don                   \
     -net nic,netdev=3Dnet0,model=3Dvirtio-net-pci            \
     -netdev user,id=3Dnet0            \
     -device ac97                    \
     -vga std                        \
     -serial mon:stdio               \
     -name "32_bit_x86"              \
     -pflash /usr/share/qemu/edk2-x86_64-code.fd

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University