Re: [PATCH 3/6] tools: remove support for running a guest with qemu-traditional

[Jan Beulich <jbeulich@xxxxxxxx>]

On 26.03.2025 17:04, Juergen Gross wrote:
> --- a/tools/firmware/hvmloader/pci.c
> +++ b/tools/firmware/hvmloader/pci.c
> @@ -108,24 +108,7 @@ void pci_setup(void)
>      uint64_t mmio_hole_size = 0;
>  
>      const char *s;
> -    /*
> -     * Do we allow hvmloader to relocate guest memory in order to
> -     * increase the size of the lowmem MMIO hole?  Defaulting to 1
> -     * here will mean that non-libxl toolstacks (including xend and
> -     * home-grown ones) means that those using qemu-xen will still
> -     * experience the memory relocation bug described below; but it
> -     * also means that those using qemu-traditional will *not*
> -     * experience any change; and it also means that there is a
> -     * work-around for those using qemu-xen, namely switching to
> -     * qemu-traditional.
> -     *
> -     * If we defaulted to 0, and failing to resize the hole caused any
> -     * problems with qemu-traditional, then there is no work-around.
> -     *
> -     * Since xend can only use qemu-traditional, I think this is the
> -     * option that will have the least impact.
> -     */
> -    bool allow_memory_relocate = 1;
> +    bool allow_memory_relocate = 0;

I think a fair part of the comment needs to stay. It's sad enough that the
issue still wasn't sorted in qemuu. Instead the other comment referred to
here also wants pruning of "qemu-traditional", I think.

> --- a/tools/firmware/hvmloader/util.c
> +++ b/tools/firmware/hvmloader/util.c
> @@ -843,14 +843,7 @@ void hvmloader_acpi_build_tables(struct acpi_config 
> *config,
>  
>      /* If the device model is specified switch to the corresponding tables */
>      s = xenstore_read("platform/device-model", "");
> -    if ( !strncmp(s, "qemu_xen_traditional", 21) )
> -    {
> -        config->dsdt_anycpu = dsdt_anycpu;
> -        config->dsdt_anycpu_len = dsdt_anycpu_len;
> -        config->dsdt_15cpu = dsdt_15cpu;
> -        config->dsdt_15cpu_len = dsdt_15cpu_len;
> -    }

Hmm, rombios.c references these two DSDTs as well, but - is that useful?
If we use dsdt_anycpu_qemu_xen when the device model is explicitly qemuu,
what sense does it make to use one of the other tables when it is
implicitly so?

Jan