From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
Julien Grall <julien.grall@arm.com>,
Jan Beulich <jbeulich@suse.com>
Subject: [Xen-devel] [RFC PATCH 1/5] docs: add feature document for Xen hypervisor sysfs-like support
Date: Wed, 11 Sep 2019 08:19:57 +0200 [thread overview]
Message-ID: <20190911062001.25931-2-jgross@suse.com> (raw)
In-Reply-To: <20190911062001.25931-1-jgross@suse.com>
On the 2019 Xen developer summit there was agreement that the Xen
hypervisor should gain support for a hierarchical name-value store
similar to the Linux kernel's sysfs.
In the beginning there should only be basic support: entries can be
added from the hypervisor itself only, there is a simple hypercall
interface to read the data.
Add a feature document for setting the base of a discussion regarding
the desired functionality and the entries to add.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
docs/features/hypervisorfs.pandoc | 110 ++++++++++++++++++++++++++++++++++++++
1 file changed, 110 insertions(+)
create mode 100644 docs/features/hypervisorfs.pandoc
diff --git a/docs/features/hypervisorfs.pandoc b/docs/features/hypervisorfs.pandoc
new file mode 100644
index 0000000000..e13a3c9b0a
--- /dev/null
+++ b/docs/features/hypervisorfs.pandoc
@@ -0,0 +1,110 @@
+% Hypervisor FS
+% Revision 1
+
+\clearpage
+
+# Basics
+---------------- ---------------------
+ Status: e.g. **Supported**
+
+ Architectures: all
+
+ Components: Hypervisor, toolstack
+---------------- ---------------------
+
+# Overview
+
+The Hypervisor FS is a hierarchical name-value store for reporting
+information to guests, especially dom0. It is similar to the Linux
+kernel's sysfs, but without the functionality to directly alter
+entries values. Entries and directories are created by the hypervisor,
+while the toolstack is able to use a hypercall to query the entry
+values.
+
+# User details
+
+With:
+
+ xenfs --ls <path>
+
+the user can list the entries of a specific path of the FS. Using:
+
+ xenfs --cat <path>
+
+the content of an entry can be retrieved.
+
+The FS structure is:
+
+ /
+ buildinfo/ directory containing build-time data
+ config contents of .config file used to build Xen
+ cpu-bugs/ x86: directory of cpu bug information
+ l1tf "Vulnerable" or "Not vulnerable"
+ mds "Vulnerable" or "Not vulnerable"
+ meltdown "Vulnerable" or "Not vulnerable"
+ spec-store-bypass "Vulnerable" or "Not vulnerable"
+ spectre-v1 "Vulnerable" or "Not vulnerable"
+ spectre-v2 "Vulnerable" or "Not vulnerable"
+ mitigations/ directory of mitigation settings
+ bti-thunk "N/A", "RETPOLINE", "LFENCE" or "JMP"
+ spec-ctrl "No", "IBRS+" or IBRS-"
+ ibpb "No" or "Yes"
+ l1d-flush "No" or "Yes"
+ md-clear "No" or "VERW"
+ l1tf-barrier "No" or "Yes"
+ active-hvm/ directory for mitigations active in hvm doamins
+ msr-spec-ctrl "No" or "Yes"
+ rsb "No" or "Yes"
+ eager-fpu "No" or "Yes"
+ md-clear "No" or "Yes"
+ active-pv/ directory for mitigations active in pv doamins
+ msr-spec-ctrl "No" or "Yes"
+ rsb "No" or "Yes"
+ eager-fpu "No" or "Yes"
+ md-clear "No" or "Yes"
+ xpti "No" or list of "dom0", "domU", "PCID on"
+ l1tf-shadow "No" or list of "dom0", "domU"
+ parameters/ directory with hypervisor parameter values
+ (boot/runtime parameters)
+
+# Technical details
+
+Access to the hypervisor filesystem is done via the stable new hypercall
+__HYPERVISOR_filesystem_op.
+
+* hypercall interface specification
+ * `xen/include/public/filesystem.h`
+* hypervisor internal files
+ * `xen/include/xen/filesystem.h`
+ * `xen/common/filesystem.c`
+* `libxenfs`
+ * `tools/libs/libxenfs/*`
+* `xenfs`
+ * `tools/misc/xenfs.c`
+
+# Testing
+
+Any new parameters or hardware mitigations should be verified to show up
+correctly in the filesystem.
+
+# Areas for improvement
+
+* More detailed access rights
+* Entries per domain and/or per cpupool
+* Possibility to modify values via filesystem access
+
+# Known issues
+
+* None
+
+# References
+
+* None
+
+# History
+
+------------------------------------------------------------------------
+Date Revision Version Notes
+---------- -------- -------- -------------------------------------------
+2019-08-29 1 Xen 4.13 Document written
+---------- -------- -------- -------------------------------------------
--
2.16.4
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next prev parent reply other threads:[~2019-09-11 6:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 6:19 [Xen-devel] [RFC PATCH 0/5] Add hypervisor sysfs-like support Juergen Gross
2019-09-11 6:19 ` Juergen Gross [this message]
2019-09-11 9:28 ` [Xen-devel] [RFC PATCH 1/5] docs: add feature document for Xen " Jan Beulich
2019-09-11 9:29 ` Juergen Gross
2019-09-11 6:19 ` [Xen-devel] [RFC PATCH 2/5] xen: add basic hypervisor filesystem support Juergen Gross
2019-09-11 6:19 ` [Xen-devel] [RFC PATCH 3/5] libs: add libxenfs Juergen Gross
2019-09-11 6:20 ` [Xen-devel] [RFC PATCH 4/5] tools: add xenfs tool Juergen Gross
2019-09-11 9:30 ` Jan Beulich
2019-09-11 9:57 ` Juergen Gross
2019-09-11 10:07 ` Jan Beulich
2019-09-11 11:34 ` Juergen Gross
2019-09-11 11:50 ` Jan Beulich
2019-09-11 12:41 ` Juergen Gross
2019-09-11 6:20 ` [Xen-devel] [RFC PATCH 5/5] xen: add /buildinfo/config entry to hypervisor filesystem Juergen Gross
2019-09-11 9:24 ` [Xen-devel] [RFC PATCH 0/5] Add hypervisor sysfs-like support Jan Beulich
2019-09-11 10:02 ` Juergen Gross
2019-09-11 11:17 ` Andrew Cooper
2019-09-11 11:29 ` Juergen Gross
2019-09-11 11:54 ` Jan Beulich
2019-09-11 13:01 ` Juergen Gross
2019-09-11 15:01 ` Jan Beulich
2019-09-11 15:06 ` Juergen Gross
2019-09-11 15:20 ` Jan Beulich
2019-09-11 15:26 ` Juergen Gross
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