[libvirt] [PATCH 1/2] conf: Forbid hugepages and <source type='file'/>

Daniel P. Berrangé berrange at redhat.com
Mon Oct 15 13:17:59 UTC 2018


On Mon, Oct 15, 2018 at 02:39:26PM +0200, Michal Privoznik wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1633562
> 
> Under <memoryBacking/> we allow users to configure various memory
> backing related knobs. However, there are some combinations that
> make no sense. For instance, requesting hugepages and file
> allocation at the same time. Forbid this configuration then.

The huge pages we allocate come from a file in /dev/hugepages,
so this description doesn't really make sense.

IIUC, what's actually happening is that you're trying to avoid
a historical bug.

> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/conf/domain_conf.c                          | 16 ++++++++++++++--
>  tests/qemuxml2argvdata/hugepages-memaccess2.xml |  1 -
>  2 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 9911d56130..ef1d5caa1c 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -4041,7 +4041,7 @@ virDomainDefPostParseMemory(virDomainDefPtr def,
>  }
>  
>  
> -static void
> +static int
>  virDomainDefPostParseMemtune(virDomainDefPtr def)
>  {
>      size_t i;
> @@ -4063,6 +4063,17 @@ virDomainDefPostParseMemtune(virDomainDefPtr def)
>              }
>          }
>      }
> +
> +    if (def->mem.nhugepages &&
> +        def->mem.source != VIR_DOMAIN_MEMORY_SOURCE_NONE &&
> +        def->mem.source != VIR_DOMAIN_MEMORY_SOURCE_ANONYMOUS) {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("unsupported combination of hugepages and source type %s"),
> +                       virDomainMemorySourceTypeToString(def->mem.source));
> +        return -1;
> +    }
> +
> +    return 0;
>  }
>  
>  
> @@ -5131,7 +5142,8 @@ virDomainDefPostParseCommon(virDomainDefPtr def,
>      if (virDomainDefPostParseMemory(def, data->parseFlags) < 0)
>          return -1;
>  
> -    virDomainDefPostParseMemtune(def);
> +    if (virDomainDefPostParseMemtune(def) < 0)
> +        return -1;
>  
>      if (virDomainDefRejectDuplicateControllers(def) < 0)
>          return -1;
> diff --git a/tests/qemuxml2argvdata/hugepages-memaccess2.xml b/tests/qemuxml2argvdata/hugepages-memaccess2.xml
> index 205f9efd92..e7f60291be 100644
> --- a/tests/qemuxml2argvdata/hugepages-memaccess2.xml
> +++ b/tests/qemuxml2argvdata/hugepages-memaccess2.xml
> @@ -8,7 +8,6 @@
>      <hugepages>
>        <page size='2048' unit='KiB' nodeset='1'/>
>      </hugepages>
> -    <source type='file'/>
>      <access mode='private'/>
>    </memoryBacking>
>    <vcpu placement='static'>4</vcpu>
> -- 
> 2.18.1
> 
> --
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Regards,
Daniel
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