Re: [PULL 9/9] hw/i386: pass RNG seed via setup_data entry

From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: "Xiaoyao Li" <xiaoyao.li@intel.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"QEMU Developers" <qemu-devel@nongnu.org>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Philippe Mathieu-DaudÃ©" <f4bug@amsat.org>,
	"Laurent Vivier" <laurent@vivier.eu>,
	"Michael S . Tsirkin" <mst@redhat.com>
Subject: Re: [PULL 9/9] hw/i386: pass RNG seed via setup_data entry
Date: Wed, 3 Aug 2022 15:11:48 +0200	[thread overview]
Message-ID: <Yup0FIOLLo0thP8u@zx2c4.com> (raw)
In-Reply-To: <YupTaZlkyy1/9FUC@redhat.com>

Hi Daniel,

On Wed, Aug 03, 2022 at 11:52:25AM +0100, Daniel P. Berrangé wrote:
> On Tue, Aug 02, 2022 at 05:13:26PM +0200, Jason A. Donenfeld wrote:
> > Hi Xiaoyao,
> > 
> > On Tue, Aug 2, 2022 at 5:06 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> > >
> > > Hi Xiaoyao,
> > >
> > > On Tue, Aug 02, 2022 at 10:53:07PM +0800, Xiaoyao Li wrote:
> > > > yes, with >= 7.1, pcmc->legacy_no_rng_seed = false by default, and RNG
> > > > seed is used.
> > >
> > > This is intended behavior. Being on by default is basically the whole
> > > point of it. Otherwise it's useless.
> > >
> > > >
> > > > > Either way, this shouldn't cause boot failures.
> > > >
> > > > It does fail booting OVMF with #PF. Below diff can fix the #PF for me.
> > >
> > > Huh, interesting. Sounds like maybe there's a bug I need to fix. Can you
> > > send me some repro instructions, and I'll look into it right away.
> > 
> > I just tried booting Fedora using OVMF and didn't have any problems. I
> > used this command line:
> 
> I managed to reproduce on a Fedora 36 host, using QEMU git master from
> today.
> 
>  $ git clone https://gitlab.com/berrange/tiny-vm-tools
>  $ cd tiny-vm-tools
>  $ ./make-tiny-image.py --run date date
>  tiny-initrd.img
>  Copy lib /lib/ld-musl-x86_64.so.1 -> /tmp/make-tiny-imagebcuv8i_b/lib/ld-musl-x86_64.so.1
>  Copy bin /usr/bin/date -> /tmp/make-tiny-imagebcuv8i_b/bin/date
>  Copy lib /lib64/libc.so.6 -> /tmp/make-tiny-imagebcuv8i_b/lib64/libc.so.6
>  Copy lib /lib64/ld-linux-x86-64.so.2 -> /tmp/make-tiny-imagebcuv8i_b/lib64/ld-linux-x86-64.so.2
> 
>  $ cp /usr/share/edk2/ovmf/OVMF_VARS.fd vars.fd
> 
>  $ ~/src/virt/qemu.git/build/qemu-system-x86_64 \
>    -blockdev node-name=file_ovmf_code,driver=file,filename=/usr/share/edk2/ovmf/OVMF_CODE.fd,auto-read-only=on,discard=unmap \
>    -blockdev node-name=drive_ovmf_code,driver=raw,read-only=on,file=file_ovmf_code \
>    -blockdev node-name=file_ovmf_vars,driver=file,filename=vars.fd,auto-read-only=on,discard=unmap \
>    -blockdev node-name=drive_ovmf_vars,driver=raw,read-only=off,file=file_ovmf_vars  \
>    -machine pc-q35-7.1,pflash0=drive_ovmf_code,pflash1=drive_ovmf_vars \
>    -kernel /boot/vmlinuz-5.18.5-200.fc36.x86_64 \
>    -initrd tiny-initrd.img \
>    -m 8000 \
>    -display none \
>    -nodefaults \
>    -serial stdio \
>    -append 'console=ttyS0 quiet'

Thanks for the info. Very helpful. Looking into it now.

Jason