On Wed, Jun 22, 2016 at 07:50:09AM -0600, Jan Beulich wrote: > >>> On 22.06.16 at 15:03, wrote: > > I've finally found what was causing long standing issue of not working > > PCI passthrough for HVM domains with qemu in stubdomain (only - without > > the other one in dom0). It looks to be this patch: > > http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=c428c9f162895cb3473f > > ab26d23ffbf41a6f293d;hp=dcccaf806a92eabb95929a67c344ac1e9ead6257 > > > > It calls xc_domain_getinfo from xc_domain_memory_mapping (to check if > > the target domain is auto-translated), but xc_domain_getinfo fails with > > EPERM in stubdomain. > > > > What would be the best solution for this? Allowing xc_domain_getinfo > > from stubdomain in xen/include/xsm/dummy.h? Currently it is uses policy > > XSM_XS_PRIV in unstable and just XSM_PRIV in 4.6 - so, maybe have some > > combination of XSM_XS_PRIV and XSM_DM_PRIV? Or maybe fix this by > > removing xc_domain_getinfo call in xc_domain_memory_mapping, possibly > > implementing the logic from that commit solely in libxl? > > Once we fixed the quirky behavior of the current implementation > (allowing information to be returned for other than the requested > domain), I see no reason why this couldn't become XSM_DM_PRIV. Can you explain this more? Is this fix backported to 4.6 and/or 4.4? > But let's ask Daniel explicitly. And in that context I then also wonder > whether the xsm_getdomaininfo() invocation shouldn't be limited to > the respective sysctl. Actually getdomaininfo is handled in two places in xsm/dummy.h: - xsm_getdomaininfo (which does nothing when XSM is disabled) - xsm_domctl (which enforce actual policy) Also reading commit message of XSM_XS_PRIV introduction, it may be useful to be able to just check if given domain is alive, without getting all the information returned by XEN_DOMCTL_getdomaininfo. I find this useful also for any other inter-domain communication (for example libxenvchan connection). But for now, XEN_DOMCTL_getdomaininfo should be allowed either when device-model domain is asking about its target domain, or calling domain is xenstore domain/privileged domain. Right? How to combine those types? Change XSM_XS_PRIV to XSM_XS_DM_PRIV (it looks like the only usage of XSM_XS_PRIV)? -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?