On 05/02/2024 17:18, Julien Grall wrote:
> Hi Juergen,
>
> On 05/02/2024 11:08, Jürgen Groß wrote:
>> On 05.02.24 11:55, Julien Grall wrote:
>>> Hi Juergen,
>>>
>>> On 05/02/2024 10:49, Juergen Gross wrote:
>>>> This series is adding 9pfs support to Xenstore-stubdom, enabling it
>>>> to do logging to a dom0 directory.
>>>>
>>>> This is a prerequisite for the final goal to add live update support
>>>> to Xenstore-stubdom, as it enables the stubdom to store its state in
>>>> a dom0 file.
>>>>
>>>> The 9pfs backend is a new daemon written from scratch. Using a
>>>> dedicated 9pfs daemon has several advantages:
>>>>
>>>> - it is using much less resources than a full blown qemu process
>>>> - it can serve multiple guests (the idea is to use it for other
>>>> infrastructure domains, like qemu-stubdom or driver domains, too)
>>>> - it is designed to support several security enhancements, like
>>>> limiting the number of files for a guest, or limiting the allocated
>>>> file system space
>>>> - it doesn't support file links (neither hard nor soft links) or
>>>> referencing parent directories via "..", minimizing the risk that
>>>> a guest can "escape" from its home directory
>>>>
>>>> Note that for now the daemon only contains the minimal needed
>>>> functionality to do logging from Xenstore-stubdom. I didn't want to
>>>> add all the 9pfs commands and security add-ons in the beginning, in
>>>> order to avoid needless efforts in case the idea of the daemon is
>>>> being rejected.
>>>>
>>>> Changes in V4:
>>>> - patch 2 of V3 was applied
>>>> - added support of reading directories
>>>> - addressed review comments
>>>>
>>>> Changes in V3:
>>>> - new patches 1, 23-25
>>>> - addressed review comments
>>>>
>>>> Changes in V2:
>>>> - support of multiple rings per device
>>>> - xenlogd->xen-9pfsd rename
>>>> - addressed review comments
>>>> - fixed some bugs
>>>>
>>>> Juergen Gross (32):
>>>> tools: add access macros for unaligned data
>>>> tools: add a new xen logging daemon
>>>> tools/xen-9pfsd: connect to frontend
>>>> tools/xen-9pfsd: add transport layer
>>>> tools/xen-9pfsd: add 9pfs response generation support
>>>> tools/xen-9pfsd: add 9pfs version request support
>>>> tools/xen-9pfsd: add 9pfs attach request support
>>>> tools/xen-9pfsd: add 9pfs walk request support
>>>> tools/xen-9pfsd: add 9pfs open request support
>>>> tools/xen-9pfsd: add 9pfs clunk request support
>>>> tools/xen-9pfsd: add 9pfs create request support
>>>> tools/xen-9pfsd: add 9pfs stat request support
>>>> tools/xen-9pfsd: add 9pfs write request support
>>>> tools/xen-9pfsd: add 9pfs read request support
>>>> tools/libs/light: add backend type for 9pfs PV devices
>>>> tools/xl: support new 9pfs backend xen_9pfsd
>>>> tools/helpers: allocate xenstore event channel for xenstore stubdom
>>>> tools/xenstored: rename xenbus_evtchn()
>>>> stubdom: extend xenstore stubdom configs
>>>> tools: add 9pfs device to xenstore-stubdom
>>>> tools/xenstored: add early_init() function
>>>> tools/xenstored: move systemd handling to posix.c
>>>> tools/xenstored: move all log-pipe handling into posix.c
>>>> tools/xenstored: move all socket handling into posix.c
>>>> tools/xenstored: get own domid in stubdom case
>>>> tools/xenstored: rework ring page (un)map functions
>>>> tools/xenstored: split domain_init()
>>>> tools/xenstored: map stubdom interface
>>>> tools/xenstored: mount 9pfs device in stubdom
>>>> tools/xenstored: add helpers for filename handling
>>>> tools/xenstored: support complete log capabilities in stubdom
>>>> tools/xenstored: have a single do_control_memreport()
>>>
>>> I haven't checked what's the state of the 9PFS patches. Can part of
>>> the xenstored changes be committed without the 9PFS changes?
>>
>> The following patches can go in without the 9pfs daemon:
>
> It looks like the gitalb CI is not happy with the following patches [1]:
>
> In function ‘free_stat’,
> inlined from ‘write_9pfs’ at 9pfront.c:935:9:
> 9pfront.c:120:14: error: ‘stat.name’ may be used uninitialized
> [-Werror=maybe-uninitialized]
> 120 | free(stat->name);
> | ~~~~^~~~~~
> 9pfront.c: In function ‘write_9pfs’:
> 9pfront.c:929:20: note: ‘stat’ declared here
> 929 | struct p9_stat stat;
> | ^~~~
>
> I think...
>
>>
>> tools/helpers: allocate xenstore event channel for xenstore stubdom
>> tools/xenstored: rename xenbus_evtchn()
>> stubdom: extend xenstore stubdom configs
>
> .. this is related to this patch. Can you have a look?
>
> I have just pushed a new branch without this patch. Let see if the CI
> [2] will pass this time.
It passed. So I committed all the patches you mentionned but "stubdom:
extend xenstore stubdom configs".
Cheers,
--
Julien Grall