[libvirt] [RFC v3 PATCH 4/5] PowerPC : Clean up qemuBuildCommandLine to remove x86-specific assumptions from generic code.

Stefan Berger stefanb at linux.vnet.ibm.com
Tue Nov 29 16:57:20 UTC 2011


On 11/29/2011 10:01 AM, Prerna Saxena wrote:
> From: Prerna Saxena<prerna at linux.vnet.ibm.com>
> Date: Mon, 21 Nov 2011 18:20:42 +0530
> Subject: [PATCH 4/5] Clean up qemuBuildCommandLine to remove x86-specific
>   assumptions from generic code.
>
> This implements the minimal set of changes needed in libvirt to launch a
> PowerPC-KVM based guest.
> It removes x86-specific assumptions about choice of serial driver backend
> from generic qemu guest commandline generation code.
> It also restricts the ACPI capability to be available for an x86 or
> x86_64 domain.
> This is not a complete solution -- it still does not guarantee libvirt
> the capability to flag non-supported options in guest XML. (Eg, an ACPI
> specification in a PowerPC guest XML will still get processed, even
> though qemu-system-ppc64 does not support it while qemu-system-x86_64 does.)
> This drawback exists because libvirt falls back on qemu to query supported
> features, and qemu '-h' blindly lists all capabilities -- irrespective
> of whether they are available while emulating a given architecture or not.
> The long-term solution would be for qemu to list out capabilities based
> on architecture and platform -- so that libvirt can cleanly make out what
> devices are supported on an arch (say 'ppc64') and platform (say, 'mac99').
>
> Signed-off-by: Prerna Saxena<prerna at linux.vnet.ibm.com>
> ---
>   src/qemu/qemu_command.c |   39 ++++++++++++++++++++++++++++++++++++---
>   src/qemu/qemu_command.h |    6 ++++++
>   2 files changed, 42 insertions(+), 3 deletions(-)
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 85b34bb..57b25d6 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -4550,8 +4550,11 @@ qemuBuildCommandLine(virConnectPtr conn,
>                   VIR_FREE(devstr);
>
>                   virCommandAddArg(cmd, "-device");
> -                virCommandAddArgFormat(cmd, "isa-serial,chardev=char%s,id=%s",
> -                                       serial->info.alias, serial->info.alias);
> +                if (!(devstr = qemuBuildChrDeviceStr(serial, def->os.arch,
> +                                                     def->os.machine)))
> +                   goto error;
> +                virCommandAddArg(cmd, devstr);
> +                VIR_FREE(devstr);
>               } else {
>                   virCommandAddArg(cmd, "-serial");
>                   if (!(devstr = qemuBuildChrArgStr(&serial->source, NULL)))
> @@ -5438,6 +5441,34 @@ qemuBuildCommandLine(virConnectPtr conn,
>       return NULL;
>   }
>
> +/* This function generates the correct '-device' string for character
> + * devices of each architecture.
> + */
> +char *
> +qemuBuildChrDeviceStr (virDomainChrDefPtr serial,
> +                       char *os_arch,
> +                       char *machine)
> +{
> +    virBuffer cmd = VIR_BUFFER_INITIALIZER;
> +
> +    if (STREQ(os_arch, "ppc64")&&  STREQ(machine, "pseries"))
> +        virBufferAsprintf(&cmd, "spapr-vty,chardev=char%s",
> +                          serial->info.alias);
> +    else
> +        virBufferAsprintf(&cmd, "isa-serial,chardev=char%s,id=%s",
> +                          serial->info.alias, serial->info.alias);
> +
> +    if (virBufferError(&cmd)) {
> +        virReportOOMError();
> +        goto error;
> +    }
> +
> +    return virBufferContentAndReset(&cmd);
> +
> + error:
> +    virBufferFreeAndReset(&cmd);
> +    return NULL;
> +}
>
>   /*
>    * This method takes a string representing a QEMU command line ARGV set
> @@ -6649,7 +6680,9 @@ virDomainDefPtr qemuParseCommandLine(virCapsPtr caps,
>       def->maxvcpus = 1;
>       def->vcpus = 1;
>       def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_UTC;
> -    def->features = (1<<  VIR_DOMAIN_FEATURE_ACPI)
> +
> +    if (STREQ(def->os.arch, "i686")||STREQ(def->os.arch, "x86_64"))
> +        def->features = (1<<  VIR_DOMAIN_FEATURE_ACPI)
>           /*| (1<<  VIR_DOMAIN_FEATURE_APIC)*/;
>       def->onReboot = VIR_DOMAIN_LIFECYCLE_RESTART;
>       def->onCrash = VIR_DOMAIN_LIFECYCLE_DESTROY;
> diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
> index dbe2fb2..1fe0394 100644
> --- a/src/qemu/qemu_command.h
> +++ b/src/qemu/qemu_command.h
> @@ -53,6 +53,12 @@ virCommandPtr qemuBuildCommandLine(virConnectPtr conn,
>                                      enum virNetDevVPortProfileOp vmop)
>       ATTRIBUTE_NONNULL(1);
>
> +/* Generate string for arch-specific '-device' parameter */
> +char *
> +qemuBuildChrDeviceStr (virDomainChrDefPtr serial,
> +                       char *os_arch,
> +                       char *machine);
Remove the space before '('.
> +
>   /* With vlan == -1, use netdev syntax, else old hostnet */
>   char * qemuBuildHostNetStr(virDomainNetDefPtr net,
>                              char type_sep,




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