[libvirt] [ v3 2/4] 1) Loader: Add a more elaborate definition.

John Ferlan jferlan at redhat.com
Mon Jun 4 12:54:50 UTC 2018


On 05/21/2018 07:10 AM, Prerna Saxena wrote:
> Augment definition to include virStorageSourcePtr that
> more comprehensively describes the nature of backing element.
> Also include flags for annotating if input XML definition is
> old-style or new-style.
> 
> 2) Parse domain XML to generate virDomainLoaderDef & virDomainNvramDef.
> 
> This patch is used to interpret domain XML and store the Loader &
> Nvram's backing definitions as virStorageSource.
> It also identifies if input XML used old or new-style declaration.
> (This will later be used by the formatter).
> 
> 3) Format the loader source appropriately.
> 
> If the initial XML used the old-style declaration as follows:
> <loader type='pflash'>/path/to/file</loader>
> 
> we format it as was read.
> 
> However, if it used new-style declaration:
> <loader type='pflash' backing='file'>
>   <source file='path/to/file'/>
> </loader>
> 
> The formatter identifies that this is a new-style format
> and renders it likewise.
> 
> 4) Plumb the loader source into generation of QEMU command line.
> 
> Given that nvram & loader elements can now be backed by a non-local
> source too, adjust all steps leading to generation of
> QEMU command line.
> 
> 5) Fix the domain def inference logic to correctly account for network-backed
> pflash devices.
> 
> 6) Bhyve: Fix command line generation to correctly pick up local loader path.
> 
> 7) virt-aa-helper: Adjust references to loader & nvram elements to correctly
> parse the virStorageSource types.
> 
> 8) Vbox: Adjust references to 'loader' and 'nvram' elements given that
> these are now represented by virStorageSourcePtr.
> 
> 9)Xen: Adjust all references to loader & nvram elements given that they are now backed by virStorageSourcePtr
> ---
>  src/bhyve/bhyve_command.c       |   6 +-
>  src/conf/domain_conf.c          | 250 +++++++++++++++++++++++++++++++++++++---
>  src/conf/domain_conf.h          |  11 +-
>  src/qemu/qemu_cgroup.c          |  13 ++-
>  src/qemu/qemu_command.c         |  21 +++-
>  src/qemu/qemu_domain.c          |  31 +++--
>  src/qemu/qemu_driver.c          |   7 +-
>  src/qemu/qemu_parse_command.c   |  30 ++++-
>  src/qemu/qemu_process.c         |  54 ++++++---
>  src/security/security_dac.c     |   6 +-
>  src/security/security_selinux.c |   6 +-
>  src/security/virt-aa-helper.c   |  14 ++-
>  src/vbox/vbox_common.c          |  11 +-
>  src/xenapi/xenapi_driver.c      |   4 +-
>  src/xenconfig/xen_sxpr.c        |  19 +--
>  src/xenconfig/xen_xm.c          |   9 +-
>  16 files changed, 409 insertions(+), 83 deletions(-)
> 

The $SUBJ and commit message are just poorly formatted.

But it pretty much shows that everything just got thrown into this one
patch and you went from there.

This series needs to progress a bit more "reasonably" to the desired
goal. Consider this progression (with the following as patch 1 of the
entire series):

1. Change path of loader to union:

struct _virDomainLoaderDef {
    union {
        char *path;
    } loader;

then compile/fix up references.

2. Create an accessor to loader.path - that way future consumers can
just fetch the source path, e.g.:

const char *
virDomainLoaderDefGetLoaderPath(virDomainLoaderDefPtr loader)
{
    return loader->loader.path;
}

Anything that accesses loader.path should change to use this via
something like:

    const char *loaderPath;
...
    loaderPath = virDomainLoaderDefGetLoaderPath(xxx)
...

Eventually this code will return either loader.path or loader.src->path
since both FILE and NETWORK storage use src->path.

3. Add virStorageSourcePtr to the loader union and modify places in the
code to use/read it. Update the domaincommon.rng, update formatdomain to
describe usage of <source> for <loader>, add genericxml2xmltests for
both "loader-source-file" and "loader-source-network" type formats for
at least "type='rom'". You could add type='pflash' tests too...

...
    union {
        char *path;
        virStorageSourcePtr src;
    } loader;
    bool useLoaderSrc;
...

The patch code to parse needs to be changed to follow more closely what
virDomainDisk{BackingStore|DefMirror}Parse does...  Alter ctxt locally
to the passed @node (and restore at the end).  It should also be able to
use the union to do the magic, consider:

    loader->loader.path = (char *) xmlNodeGetContent(node);

    /* When not present, could return '' */
    if (virStringIsEmpty(loader->loader.path))
        VIR_FREE(loader->loader.path);

    /* See if we need to look for new style <source...> subelement */
    if (!loader->loader.path) {
        xmlNodePtr source;

        if (!(source = virXPathNode("./source", ctxt))) {
            virReportError(VIR_ERR_XML_ERROR, "%s"
                           _("missing os loader source"));
            goto cleanup;
        }

        if (VIR_ALLOC(loader->loader.src) < 0)
            goto cleanup;

        if ((tmp = virXMLPropString(source, "file")))
            loader->loader.src->type = VIR_STORAGE_TYPE_FILE;
        else if ((tmp = virXMLPropString(source, "protocol")))
            loader->loader.src->type = VIR_STORAGE_TYPE_NETWORK;

        if (loader->loader.src->type == VIR_STORAGE_TYPE_NONE) {
            virReportError(VIR_ERR_XML_ERROR,
                           _("unknown loader source type: '%s"), tmp);
            goto cleanup;
        }

        if (virDomainStorageSourceParse(source, ctxt,
loader->loader.src, 0) < 0)
            goto cleanup;

        loader->useLoaderSrc = true;
    }


Then do the similar set of changes for nvram...  Although for this one -
it's slightly trickier since <nvram> is optional...  You'll probably
also need to modify qemuDomainDefPostParse to not automagically generate
an nvram.path if you're using <source>.

Once the xml2xml portion is done, the next patch alters qemu_command,
adds more tests, etc. Since you have generic xml2xml files, you probably
could just create a link from the qemuxml2argvdata directory or
create/use new files.  Eventually it'd be nice for hte qemuxml2* code to
be able to use the generic xml files, but that's outside this scope.

BTW: I wouldn't bother with too many qemu_parse_command.c changes. Just
do the minimum. That code is so far out of date it's going to take a
solid effort to bring it back to today's options.

In any case, there's a lot of changes to be made so it's really not
worth going through each of the files in depth... I'll just point out
the domain_conf.h changes.

John


[...]


> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index a78fdee..fb44a90 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -1856,15 +1856,22 @@ typedef enum {
>  
>  VIR_ENUM_DECL(virDomainLoader)
>  
> +struct _virStorageSource;
> +typedef struct _virStorageSource *virStorageSourcePtr;
> +

The above is not necessary.

>  typedef struct _virDomainLoaderDef virDomainLoaderDef;
>  typedef virDomainLoaderDef *virDomainLoaderDefPtr;
>  struct _virDomainLoaderDef {
> -    char *path;
> +    virStorageSourcePtr src;

Eventually:

    union {
        char *path;
        virStorageSourcePtr src;
    } loaderSource;
    bool useLoaderSrc;


>      int readonly;   /* enum virTristateBool */
>      virDomainLoader type;
>      int secure;     /* enum virTristateBool */
> -    char *nvram;    /* path to non-volatile RAM */
> +    virStorageSourcePtr nvram;  /* path to non-voliatile RAM */

Eventually:

    union {
        char *nvram;    /* path to non-volatile RAM */
        virStorageSourcePtr src;
    } nvramSource;
    bool useNvramSrc;

>      char *templt;   /* user override of path to master nvram */
> +    bool oldStyleLoader;  /* is this an old-style XML formatting,
> +                           * ie, absolute path is directly specified? */
> +    bool oldStyleNvram;   /* is this an old-style XML formatting,
> +                           * ie, absolute path is directly specified? */

The two are replaced by the use{Loader|Nvram}Src

>  };
>  

You'll need to add API's for the fetch of the loader and nvram paths

[...]




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