[libvirt] [PATCH 14/15] qemu: conf: Add debug option to allow disabling qemu capabilities
In cases when e.g. a new feature breaks upstream behaviour it's useful
to allow users to disable the new feature to verify the regression and
possibly use it as a workaround until a fix is available.
The new qemu.conf option named "capability_filters" allows to remove
qemu capabilities from the detected bitmap.
This patch introduces the configuration infrastructure to parse the
option and pass it around.
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
src/qemu/libvirtd_qemu.aug | 3 +++
src/qemu/qemu.conf | 7 +++++++
src/qemu/qemu_conf.c | 17 +++++++++++++++++
src/qemu/qemu_conf.h | 2 ++
src/qemu/test_libvirtd_qemu.aug.in | 3 +++
5 files changed, 32 insertions(+)
diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug
index b311f02da6..6821cc4a29 100644
--- a/src/qemu/libvirtd_qemu.aug
+++ b/src/qemu/libvirtd_qemu.aug
@@ -126,6 +126,8 @@ module Libvirtd_qemu =
let swtpm_entry = str_entry "swtpm_user"
| str_entry "swtpm_group"
+ let capability_filters_entry = str_array_entry "capability_filters"
+
(* Each entry in the config is one of the following ... *)
let entry = default_tls_entry
| vnc_entry
@@ -147,6 +149,7 @@ module Libvirtd_qemu =
| vxhs_entry
| nbd_entry
| swtpm_entry
+ | capability_filters_entry
let comment = [ label "#comment" . del /#[ \t]*/ "# " . store
/([^ \t\n][^\n]*)?/ . del /\n/ "\n" ]
let empty = [ label "#empty" . eol ]
diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf
index 5a85789d81..1969b3f0a1 100644
--- a/src/qemu/qemu.conf
+++ b/src/qemu/qemu.conf
@@ -825,3 +825,10 @@
#
#swtpm_user = "tss"
#swtpm_group = "tss"
+
+# For debugging and testing purposes it's sometimes useful to be able to disable
+# libvirt behaviour based on the capabilities of the qemu process. This option
+# allows to do so. DO _NOT_ use in production and beaware that the behaviour
+# may change across versions.
+#
+#capability_filters = [ "capname" ]
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 745e0f21bd..8312f99f80 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -381,6 +381,8 @@ static void virQEMUDriverConfigDispose(void *obj)
VIR_FREE(cfg->memoryBackingDir);
VIR_FREE(cfg->swtpmStorageDir);
+
+ virStringListFree(cfg->capabilityfilters);
}
@@ -984,6 +986,18 @@ virQEMUDriverConfigLoadSWTPMEntry(virQEMUDriverConfigPtr cfg,
}
+static int
+virQEMUDriverConfigLoadCapsFiltersEntry(virQEMUDriverConfigPtr cfg,
+ virConfPtr conf)
+{
+ if (virConfGetValueStringList(conf, "capability_filters", false,
+ &cfg->capabilityfilters) < 0)
+ return -1;
+
+ return 0;
+}
+
+
int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
const char *filename,
bool privileged)
@@ -1053,6 +1067,9 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
if (virQEMUDriverConfigLoadSWTPMEntry(cfg, conf) < 0)
goto cleanup;
+ if (virQEMUDriverConfigLoadCapsFiltersEntry(cfg, conf) < 0)
+ goto cleanup;
+
ret = 0;
cleanup:
diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
index 386e774653..8bef009bc9 100644
--- a/src/qemu/qemu_conf.h
+++ b/src/qemu/qemu_conf.h
@@ -218,6 +218,8 @@ struct _virQEMUDriverConfig {
uid_t swtpm_user;
gid_t swtpm_group;
+
+ char **capabilityfilters;
};
/* Main driver state */
diff --git a/src/qemu/test_libvirtd_qemu.aug.in b/src/qemu/test_libvirtd_qemu.aug.in
index fea1d308b7..50b728ad22 100644
--- a/src/qemu/test_libvirtd_qemu.aug.in
+++ b/src/qemu/test_libvirtd_qemu.aug.in
@@ -104,3 +104,6 @@ module Test_libvirtd_qemu =
{ "pr_helper" = "/usr/bin/qemu-pr-helper" }
{ "swtpm_user" = "tss" }
{ "swtpm_group" = "tss" }
+{ "capability_filters"
+ { "1" = "capname" }
+}
--
2.21.0