Re: [libvirt] [PATCH] virDomainDefCopy: Skip ostype checks
On Sat, Jun 02, 2018 at 12:57:39PM +0200, Michal Privoznik wrote:
When parsing domain XML the virCapsDomainData lookup is performed
in order to fill in missing def->os.arch and def->os.machine
strings. Well, when doing copy of already existing virDomainDef
we don't want any automagic fill in of defaults (and those two
strings are going to be provided at this point anyway by first
parse of the domain XML).
The sentence in parentheses documents an inefficiency -
If we have machine and arch, the DomainDataLookup call is pointless,
unless we want to validate it.
What is even worse is that we do not look up capabilities for
parsed emulator path rather than some generic capabilities for
s/than//
parsed arch. Therefore, if emulator points to qemu under
non-default path (say $HOME/qemu-system-arm) but there's no such
qemu under the default path (say /usr/bin/qemu-system-arm) the
capabilities lookup fails and creating the copy is denied.
This is downright a bug - we should be using the specified emulator
path to fill the machine type even for new domains. Are you able
to define a new domain without having a default emulator for it?
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/conf/domain_conf.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 86814d5f64..f36a1bfe79 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -28397,7 +28397,8 @@ virDomainDefCopy(virDomainDefPtr src,
virDomainDefPtr ret;
unsigned int format_flags = VIR_DOMAIN_DEF_FORMAT_SECURE;
unsigned int parse_flags = VIR_DOMAIN_DEF_PARSE_INACTIVE |
- VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE;
+ VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE |
+ VIR_DOMAIN_DEF_PARSE_SKIP_OSTYPE_CHECKS;
For missing QEMU emulator, we postpone all the stuff depending
on qemuCaps until domain startup:
commit 7726d1581f9e433a106f45ed87ec95ece575f817
qemu: Implement postParse callback skipping on config reload
Ideally, we'd remove this flag, move the automagic to PostParse
and make it non-fatal in the same way, but I don't know how much would
that break.
Practically, this hunk is an improvement. Hoping you'll address the
newly-defined domain bug as well:
Reviewed-by: Ján Tomko <jtomko(a)redhat.com>
Jano
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