[libvirt] [PATCH] Fix libvirtd restart for domains with PCI passthrough devices

[Daniel Veillard]

On Fri, Jan 22, 2010 at 11:40:39AM -0500, Chris Lalancette wrote:
> When libvirtd shuts down, it places a <state/> tag in the XML
> state file it writes out for guests with PCI passthrough
> devices.  For devices that are attached at bootup time, the
> state tag is empty.  However, at libvirtd startup time, it
> ignores anything with a <state/> tag in the XML, effectively
> hiding the guest.
> 
> I can think of at least 3 ways to fix this:
> 
> 1)  Don't throw an error on "unknown" tags in
> virDomainHostdevSubsysPciDefParseXML().
> 2)  Have virDomainLoadAllConfigs() pass the
> VIR_DOMAIN_XML_INTERNAL_STATUS flag when parsing the domain
> XML.
> 3)  Remove the check for VIR_DOMAIN_XML_INTERNAL_STATUS
> when parsing the XML.
> 
> I chose approach 3).  My reasoning for this is that the
> <state> tag is a legitimate part of the XML, so we should
> always offer to parse it.  This fixes the problem with
> reconnecting to domains that have PCI passthrough devices.
> 
> Signed-off-by: Chris Lalancette <clalance at redhat.com>
> ---
>  src/conf/domain_conf.c |    5 ++---
>  1 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 74c2337..595c46c 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -2876,7 +2876,7 @@ static int
>  virDomainHostdevSubsysPciDefParseXML(virConnectPtr conn,
>                                       const xmlNodePtr node,
>                                       virDomainHostdevDefPtr def,
> -                                     int flags) {
> +                                     int flags ATTRIBUTE_UNUSED) {
>  
>      int ret = -1;
>      xmlNodePtr cur;
> @@ -2890,8 +2890,7 @@ virDomainHostdevSubsysPciDefParseXML(virConnectPtr conn,
>  
>                  if (virDomainDevicePCIAddressParseXML(conn, cur, addr) < 0)
>                      goto out;
> -            } else if ((flags & VIR_DOMAIN_XML_INTERNAL_STATUS) &&
> -                       xmlStrEqual(cur->name, BAD_CAST "state")) {
> +            } else if (xmlStrEqual(cur->name, BAD_CAST "state")) {
>                  /* Legacy back-compat. Don't add any more attributes here */
>                  char *devaddr = virXMLPropString(cur, "devaddr");
>                  if (devaddr &&

  I'm not sure, it feels like 2/ is the most specific change possible to
this problem, but 3/ makes sense too, I just don't know if there is any
side effect.

  So ACK to this patch but let's keep an eye on testing in the next
  week,

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel at veillard.com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/