Re: absolute firmware path made relocatable in qemu 5.2.0

[Dave <dave@0bits.com>]

Thanks Paola,

We are still in testing and that's the only thing we've uncovered so far 
with the new 5.2.0. I will post if the ops guys find anything else.

Dave

On 12/01/2021 20:53, Paolo Bonzini wrote:
> 
> 
> Il mar 12 gen 2021, 17:48 Dave <dave@0bits.com <mailto:dave@0bits.com>> 
> ha scritto:
> 
>     Hi Paolo,
> 
>     While this (option 2) partially works, it will still search for
>     /nonexistent/libexec/qemu-bridge-helper for example so seems that some
>     paths are still absolute and some relative.
> 
> 
> Ok, that's a bug that can be fixed in 5.2.1. Are there other instances?
> 
> 
>     To explain, what we are expecting that we compile one binary with the
>     relevant options, test that and then it goes into production. If we
>     compile with --prefix=/usr (it's final resting place will be /usr/bin)
>     then everything works as expected once it is in production (since
>     /usr/share/qemu, /usr/libexec, /etc/qemu exists as expected).  However
>     when we are testing the binary in a directory /root/qemu/5.2.0 with
>     --prefix=/usr it breaks since it converts the firmware and bios
>     paths to
>     /root/qemu/5.2.0/../share/qemu. This means we need to recompile twice
>     with relevant prefixes since if i use --prefix=/nonexistent then we
>     can't find the qemu-bridge-helper when the binary goes into production.
> 
>     It would be nicer with the relocatable binary took some fixed paths
>     from
>     /etc/qemu.conf for the bridge-helper, firmware, bios, qemu-ifup/down.
> 
>     thanks
>     Dave
> 
> 
>     On 12/01/2021 18:48, Paolo Bonzini wrote:
>      > On 12/01/21 15:05, Dave wrote:
>      >> Is seem that absolute firmwarepath compilation option is
>     converted  to
>      >> relocatable in 5.2.0 qemu.
>      >>
>      >> # QEMU configure log Tue 12 Jan 14:46:41 GST 2021
>      >> # Configured with: '../configure' '--prefix=/usr'
>      >> '--sysconfdir=/etc/qemu' '--disable-bochs'
>      >> '*--firmwarepath=/usr/share/qemu:/usr/share/qemu-firmware*'
>      >> #
>      >
>      > Yes, all paths within the prefix are relocated.  The workaround is
>      > simply to configure the intended prefix with configure:
>      >
>      > ./configure --prefix=/root/qemu ...
>      >
>      > or if you don't know the prefix:
>      >
>      > ./configure --prefix=/nonexistent ...
>      >
>      > Because /usr/share/qemu and /usr/share/qemu-firmware are outside
>     /usr,
>      > they will be treated as absolute just like /etc/qemu.
>      >
>      > Thanks,
>      >
>      > Paolo
>      >
>      >> And trying to run the executable
>      >>
>      >>     bash-5.1# ./qemu-system-x86_64
>      >>     qemu: could not load PC BIOS 'bios-256k.bin'
>      >>
>      >> If i print out the resultant binary paths
>      >>
>      >>     bash-5.1# ./qemu-system-x86_64 -L help
>      >>     /root/qemu/../share/qemu
>      >>     /root/qemu/../share/qemu-firmware
>      >>
>      >> So there is no way to have a absolute path for firmware /bios
>     and all
>      >> qemu's that we test need to be at the right directory nesting to
>     find
>      >> firmware, bios etc or else they all need their own duplicate
>     firmware
>      >> files. Firmware path needs to honor the absolute paths i believe.
>      >>
>      >
>