From: Julien Grall Date: Wed, 19 Jun 2024 11:47:28 +0000 (+0100) Subject: Revert "docs/features/dom0less: Update the late XenStore init protocol" X-Git-Tag: 4.19.0-rc1~52 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=443c488a0b3676b5c001069d14890cd8d0ec2c1d;p=xen.git Revert "docs/features/dom0less: Update the late XenStore init protocol" Michal reported that the gitlab CI is failing because of this series [1]. This reverts commit 53c5c99e8744495395c1274595d6ca55947d1d6a. [1] https://gitlab.com/xen-project/xen/-/pipelines/1338067978 Signed-off-by: Julien Grall --- diff --git a/docs/features/dom0less.pandoc b/docs/features/dom0less.pandoc index 8b178edee0..725afa0558 100644 --- a/docs/features/dom0less.pandoc +++ b/docs/features/dom0less.pandoc @@ -110,10 +110,9 @@ hotplug PV drivers to dom0less guests. E.g. xl network-attach domU. The implementation works as follows: - Xen allocates the xenstore event channel for each dom0less domU that has the "xen,enhanced" property, and sets HVM_PARAM_STORE_EVTCHN -- Xen allocates the xenstore page and sets HVM_PARAM_STORE_PFN as well - as the connection status to XENSTORE_RECONNECT. -- Dom0less domU kernels check that HVM_PARAM_STORE_PFN is set to - ~0ULL (invalid) or the connection status is *not* XENSTORE_CONNECTED. +- Xen does *not* allocate the xenstore page and sets HVM_PARAM_STORE_PFN + to ~0ULL (invalid) +- Dom0less domU kernels check that HVM_PARAM_STORE_PFN is set to invalid - Old kernels will continue without xenstore support (Note: some old buggy kernels might crash because they don't check the validity of HVM_PARAM_STORE_PFN before using it! Disable "xen,enhanced" in @@ -122,14 +121,13 @@ The implementation works as follows: channel (HVM_PARAM_STORE_EVTCHN) before continuing with the initialization - Once dom0 is booted, init-dom0less is executed: - - it gets the xenstore shared page from HVM_PARAM_STORE_PFN + - it allocates the xenstore shared page and sets HVM_PARAM_STORE_PFN - it calls xs_introduce_domain - Xenstored notices the new domain, initializes interfaces as usual, and sends an event channel notification to the domain using the xenstore event channel (HVM_PARAM_STORE_EVTCHN) - The Linux domU kernel receives the event channel notification, checks - HVM_PARAM_STORE_PFN and the connection status again and continue with - the initialization + HVM_PARAM_STORE_PFN again and continue with the initialization Limitations