Re: [Xen-devel] [PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries
On 10/06/15 16:15, Wei Liu wrote: On Wed, Jun 10, 2015 at 05:01:27PM +0100, Ian Jackson wrote: Ian Campbell writes ([PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries): [stuff] Most of this looks good to me. As part of this change I've begun to get rid of the osdep interface layer, since it is obsolete and just gets in the way. IIRC there were some tricks being played to use this on rumpkernels to mix and match facilities from xc_minios.c and xc_netbsd.c. Replacing those tricks with appropriate #ifdefs would be fine. FYI I think I will write more glue code to make rump kernel to just use netbsd code, because they don't want to expose underlying minios functionalities to application level. It's not so much that we outright don't want to as prefer not to. If there's a strong reason, e.g. a measurably significant performance improvement, then we can talk. However, anything calling past the libc interface is dipping into internal interfaces. We make no guarantee about internal interface stability. One good summary of 8 years of rump kernel development would be lack of compartmentalization always comes back to bite you, so IMO it's better to conceptually maintain separation even where not enforced by a MMU and just make everything go through the guaranteed-stable syscall interfaces. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
[Xen-devel] [PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries
In 1431963008.4944.80.ca...@citrix.com I proposed stabilising some parts of the libxenctrl API/ABI by disaggregating into separate libraries. As a proof of concept these three intertangled series[0] splits out the xentoollog and event channel device interfaces. Still to come would be at least the grant table interfaces and a basic hypercall making facility (including the buffers etc), followed by libraries for specific out of tree purposes (device model, kexec). The new libraries use linker version-scripts to hopefully make future ABI changes be possible in a compatible way. I decided to move the event channel functions into a new namespace (xenevtchn_*) in order to provide a clean break from the old unstable interfaces to the new stable ones. I've updated all the in tree callers and qemu-trad and provided a compat shim in libxenctrl for other out of tree users (which is used for qemu-upstream). My hope is that this can be removed sooner rather than later. I intend to do the same for the other interfaces. I haven't done this for the xentoollog stuff since it already had a separate namespace. I mulled over putting everything into tools/libs/FOO instead of tools/libxenFOO, I didn't but I could if people think it is worthwhile. Eventually I'd like to split libxc into libxenguest and libxenctrl to cut down on the amount of strange cross talk... As part of this change I've begun to get rid of the osdep interface layer, since it is obsolete and just gets in the way. IIRC there were some tricks being played to use this on rumpkernels to mix and match facilities from xc_minios.c and xc_netbsd.c. Once the hypercall calling and grant interfaces are in separate libraries are split this would become easier since each library can independently choose the desired backend. The whole thing has been build tested on Linux and stubdoms, but not FreeBSD, NetBSD or Solaris. It's certainly not impossible that I've not got the #includes in the new files quite right. Ian. [0] There are 3 series, against xen.git, mini-os.git and qemu-xen-trad.git. The patches against xen.git point to the patches in the other two trees with instructions to update the relevant Config.mk field. The perils of changing unstable interfaces... ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries
On Wed, Jun 10, 2015 at 05:01:27PM +0100, Ian Jackson wrote: Ian Campbell writes ([PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries): [stuff] Most of this looks good to me. As part of this change I've begun to get rid of the osdep interface layer, since it is obsolete and just gets in the way. IIRC there were some tricks being played to use this on rumpkernels to mix and match facilities from xc_minios.c and xc_netbsd.c. Replacing those tricks with appropriate #ifdefs would be fine. FYI I think I will write more glue code to make rump kernel to just use netbsd code, because they don't want to expose underlying minios functionalities to application level. Wei. Ian. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries
Ian Campbell writes ([PATCH RFC 0/6+2+2] Begin to disentangle libxenctrl and provide some stable libraries): [stuff] Most of this looks good to me. As part of this change I've begun to get rid of the osdep interface layer, since it is obsolete and just gets in the way. IIRC there were some tricks being played to use this on rumpkernels to mix and match facilities from xc_minios.c and xc_netbsd.c. Replacing those tricks with appropriate #ifdefs would be fine. Ian. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
