[libvirt] [PATCH 2/2] qemu: use -incoming fd:n to avoid qemu holding fd indefinitely
Eric Blake
eblake at redhat.com
Wed Dec 22 22:27:49 UTC 2010
https://bugzilla.redhat.com/show_bug.cgi?id=620363
When using -incoming stdio or -incoming exec:cat, qemu keeps the
stdin fd open long after the migration is complete. Not to
mention that exec:cat is horribly inefficient, by doubling the
I/O and going through a popen interface in qemu.
The new -incoming fd: of qemu 0.12.0 closes the fd after using
it, and allows us to bypass an intermediary cat process for
less I/O.
It would also be possible to fix this bug for qemu < 0.12.0, by
creating a dummy 'cat' process that reads from real fd and writes to a
pipe, and pass the other end of the pipe into -incoming exec:cat or
-incoming stdio, at the expense of even more I/O. I don't know if
that is worth the patch, though.
* src/qemu/qemu_command.h (qemuBuildCommandLine): Add parameter.
* src/qemu/qemu_command.c (qemuBuildCommandLine): Support
migration via fd: when possible. Consolidate migration handling
into one spot, now that it is more complex.
* src/qemu/qemu_driver.c (qemudStartVMDaemon): Update caller.
* tests/qemuxml2argvtest.c (mymain): Likewise.
* tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.args: New file.
* tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.xml: Likewise.
---
src/qemu/qemu_command.c | 82 +++++++++++++-------
src/qemu/qemu_command.h | 1 +
src/qemu/qemu_driver.c | 7 +-
.../qemuxml2argv-restore-v2-fd.args | 1 +
.../qemuxml2argv-restore-v2-fd.xml | 25 ++++++
tests/qemuxml2argvtest.c | 30 +++++--
6 files changed, 103 insertions(+), 43 deletions(-)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.args
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.xml
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index bde3904..3187858 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -2452,6 +2452,7 @@ qemuBuildCommandLine(virConnectPtr conn,
bool monitor_json,
unsigned long long qemuCmdFlags,
const char *migrateFrom,
+ int migrateFd,
virDomainSnapshotObjPtr current_snapshot,
enum virVMOperationType vmop)
{
@@ -2479,33 +2480,6 @@ qemuBuildCommandLine(virConnectPtr conn,
virUUIDFormat(def->uuid, uuid);
- /* Migration is very annoying due to wildly varying syntax & capabilities
- * over time of KVM / QEMU codebases
- */
- if (migrateFrom) {
- if (STRPREFIX(migrateFrom, "tcp")) {
- if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_TCP)) {
- qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
- "%s", _("TCP migration is not supported with this QEMU binary"));
- return NULL;
- }
- } else if (STREQ(migrateFrom, "stdio")) {
- if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC) {
- migrateFrom = "exec:cat";
- } else if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_KVM_STDIO)) {
- qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
- "%s", _("STDIO migration is not supported with this QEMU binary"));
- return NULL;
- }
- } else if (STRPREFIX(migrateFrom, "exec")) {
- if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC)) {
- qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
- "%s", _("STDIO migration is not supported with this QEMU binary"));
- return NULL;
- }
- }
- }
-
emulator = def->emulator;
/*
@@ -3880,8 +3854,58 @@ qemuBuildCommandLine(virConnectPtr conn,
}
}
- if (migrateFrom)
- virCommandAddArgList(cmd, "-incoming", migrateFrom, NULL);
+ /* Migration is very annoying due to wildly varying syntax &
+ * capabilities over time of KVM / QEMU codebases.
+ */
+ if (migrateFrom) {
+ virCommandAddArg(cmd, "-incoming");
+ if (STRPREFIX(migrateFrom, "tcp")) {
+ if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_TCP)) {
+ qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("TCP migration is not supported with "
+ "this QEMU binary"));
+ goto error;
+ }
+ virCommandAddArg(cmd, migrateFrom);
+ } else if (STREQ(migrateFrom, "stdio")) {
+ if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_FD) {
+ virCommandAddArgFormat(cmd, "fd:%d", migrateFd);
+ virCommandTransferFD(cmd, migrateFd);
+ } else if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC) {
+ virCommandAddArg(cmd, "exec:cat");
+ virCommandSetInputFD(cmd, migrateFd);
+ } else if (qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_KVM_STDIO) {
+ virCommandAddArg(cmd, migrateFrom);
+ virCommandSetInputFD(cmd, migrateFd);
+ } else {
+ qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("STDIO migration is not supported "
+ "with this QEMU binary"));
+ goto error;
+ }
+ } else if (STRPREFIX(migrateFrom, "exec")) {
+ if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC)) {
+ qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("EXEC migration is not supported "
+ "with this QEMU binary"));
+ goto error;
+ }
+ virCommandAddArg(cmd, migrateFrom);
+ } else if (STRPREFIX(migrateFrom, "fd")) {
+ if (!(qemuCmdFlags & QEMUD_CMD_FLAG_MIGRATE_QEMU_FD)) {
+ qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("FD migration is not supported "
+ "with this QEMU binary"));
+ goto error;
+ }
+ virCommandAddArg(cmd, migrateFrom);
+ virCommandTransferFD(cmd, migrateFd);
+ } else {
+ qemuReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("unknown migration protocol"));
+ goto error;
+ }
+ }
/* QEMU changed its default behavior to not include the virtio balloon
* device. Explicitly request it to ensure it will be present.
diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
index 4c42a10..bdab911 100644
--- a/src/qemu/qemu_command.h
+++ b/src/qemu/qemu_command.h
@@ -44,6 +44,7 @@ virCommandPtr qemuBuildCommandLine(virConnectPtr conn,
bool monitor_json,
unsigned long long qemuCmdFlags,
const char *migrateFrom,
+ int migrateFd,
virDomainSnapshotObjPtr current_snapshot,
enum virVMOperationType vmop)
ATTRIBUTE_NONNULL(1);
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 924446f..0511266 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2803,7 +2803,7 @@ static int qemudStartVMDaemon(virConnectPtr conn,
vm->def->id = driver->nextvmid++;
if (!(cmd = qemuBuildCommandLine(conn, driver, vm->def, priv->monConfig,
priv->monJSON != 0, qemuCmdFlags,
- migrateFrom,
+ migrateFrom, stdin_fd,
vm->current_snapshot, vmop)))
goto cleanup;
@@ -2853,9 +2853,6 @@ static int qemudStartVMDaemon(virConnectPtr conn,
VIR_WARN("Executing %s", vm->def->emulator);
virCommandSetPreExecHook(cmd, qemudSecurityHook, &hookData);
- if (stdin_fd != -1)
- virCommandSetInputFD(cmd, stdin_fd);
-
virCommandSetOutputFD(cmd, &logfile);
virCommandSetErrorFD(cmd, &logfile);
virCommandNonblockingFDs(cmd);
@@ -6146,7 +6143,7 @@ static char *qemuDomainXMLToNative(virConnectPtr conn,
if (!(cmd = qemuBuildCommandLine(conn, driver, def,
&monConfig, false, qemuCmdFlags,
- NULL, NULL, VIR_VM_OP_NO_OP)))
+ NULL, -1, NULL, VIR_VM_OP_NO_OP)))
goto cleanup;
ret = virCommandToString(cmd);
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.args b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.args
new file mode 100644
index 0000000..5464d37
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.args
@@ -0,0 +1 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -hda /dev/HostVG/QEMUGuest1 -net none -serial none -parallel none -usb -incoming fd:7
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.xml b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.xml
new file mode 100644
index 0000000..ed91e37
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2-fd.xml
@@ -0,0 +1,25 @@
+<domain type='qemu'>
+ <name>QEMUGuest1</name>
+ <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+ <memory>219200</memory>
+ <currentMemory>219200</currentMemory>
+ <vcpu>1</vcpu>
+ <os>
+ <type arch='i686' machine='pc'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu</emulator>
+ <disk type='block' device='disk'>
+ <source dev='/dev/HostVG/QEMUGuest1'/>
+ <target dev='hda' bus='ide'/>
+ <address type='drive' controller='0' bus='0' unit='0'/>
+ </disk>
+ <controller type='ide' index='0'/>
+ <memballoon model='virtio'/>
+ </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 6760f67..eb0a401 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -31,6 +31,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
const char *cmdline,
unsigned long long extraFlags,
const char *migrateFrom,
+ int migrateFd,
bool expectError) {
char argvData[MAX_FILE];
char *expectargv = &(argvData[0]);
@@ -113,7 +114,8 @@ static int testCompareXMLToArgvFiles(const char *xml,
if (!(cmd = qemuBuildCommandLine(conn, &driver,
vmdef, &monitor_chr, false, flags,
- migrateFrom, NULL, VIR_VM_OP_CREATE)))
+ migrateFrom, migrateFd, NULL,
+ VIR_VM_OP_CREATE)))
goto fail;
if (!!virGetLastError() != expectError) {
@@ -161,6 +163,7 @@ struct testInfo {
const char *name;
unsigned long long extraFlags;
const char *migrateFrom;
+ int migrateFd;
bool expectError;
};
@@ -173,7 +176,8 @@ static int testCompareXMLToArgvHelper(const void *data) {
snprintf(args, PATH_MAX, "%s/qemuxml2argvdata/qemuxml2argv-%s.args",
abs_srcdir, info->name);
return testCompareXMLToArgvFiles(xml, args, info->extraFlags,
- info->migrateFrom, info->expectError);
+ info->migrateFrom, info->migrateFd,
+ info->expectError);
}
@@ -218,10 +222,10 @@ mymain(int argc, char **argv)
if (cpuMapOverride(map) < 0)
return EXIT_FAILURE;
-# define DO_TEST_FULL(name, extraFlags, migrateFrom, expectError) \
+# define DO_TEST_FULL(name, extraFlags, migrateFrom, migrateFd, expectError) \
do { \
const struct testInfo info = { \
- name, extraFlags, migrateFrom, expectError \
+ name, extraFlags, migrateFrom, migrateFd, expectError \
}; \
if (virtTestRun("QEMU XML-2-ARGV " name, \
1, testCompareXMLToArgvHelper, &info) < 0) \
@@ -229,7 +233,7 @@ mymain(int argc, char **argv)
} while (0)
# define DO_TEST(name, extraFlags, expectError) \
- DO_TEST_FULL(name, extraFlags, NULL, expectError)
+ DO_TEST_FULL(name, extraFlags, NULL, -1, expectError)
/* Unset or set all envvars here that are copied in qemudBuildCommandLine
* using ADD_ENV_COPY, otherwise these tests may fail due to unexpected
@@ -423,10 +427,18 @@ mymain(int argc, char **argv)
DO_TEST("hostdev-pci-address-device", QEMUD_CMD_FLAG_PCIDEVICE |
QEMUD_CMD_FLAG_DEVICE | QEMUD_CMD_FLAG_NODEFCONFIG, false);
- DO_TEST_FULL("restore-v1", QEMUD_CMD_FLAG_MIGRATE_KVM_STDIO, "stdio", false);
- DO_TEST_FULL("restore-v2", QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC, "stdio", false);
- DO_TEST_FULL("restore-v2", QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC, "exec:cat", false);
- DO_TEST_FULL("migrate", QEMUD_CMD_FLAG_MIGRATE_QEMU_TCP, "tcp:10.0.0.1:5000", false);
+ DO_TEST_FULL("restore-v1", QEMUD_CMD_FLAG_MIGRATE_KVM_STDIO, "stdio", 7,
+ false);
+ DO_TEST_FULL("restore-v2", QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC, "stdio", 7,
+ false);
+ DO_TEST_FULL("restore-v2", QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC, "exec:cat", 7,
+ false);
+ DO_TEST_FULL("restore-v2-fd", QEMUD_CMD_FLAG_MIGRATE_QEMU_FD, "stdio", 7,
+ false);
+ DO_TEST_FULL("restore-v2-fd", QEMUD_CMD_FLAG_MIGRATE_QEMU_FD, "fd:7", 7,
+ false);
+ DO_TEST_FULL("migrate", QEMUD_CMD_FLAG_MIGRATE_QEMU_TCP,
+ "tcp:10.0.0.1:5000", -1, false);
DO_TEST("qemu-ns", 0, false);
--
1.7.3.3
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