1:03 p.m.
Currently we are pretty strict about what emulator binary we allow for
QEMU guests on x86 arches. In particular, for arch+domain type combos:
- i686+qemu must use 'qemu' binary
- x86_64+qemu must use 'qemu-system-x86_64' binary
- kvm must use 'qemu-kvm' or 'kvm' binaries
- i686+kvm on x86_64 host is not allowed
These restrictions are overkill because
- i686+qemu could use 'qemu-system-x86_64' if '-cpu qemu32' is added
- i686+qemu could use 'qemu-kvm' if '-cpu qemu32 -no-kvm' is added
- x86_64+qemu could use 'qemu-kvm' if '-no-kvm' is added
- i686+kvm on x86_64 host can be used if '-cpu qemu32' is added
This patch makes QEMU driver more flexible in this way when setting up
its capabilities information. It also makes it aware of the -no-kvm
and -cpu flag, using them where required by the os type + arch + emulator
combinations specified in the guest XML.
This should finally remove the confusion where a user in virt-manager
selectrs 'i686' and then wonders why we've disallowed choice of
'kvm'.
It also fixes 'virsh version' when only qemu-kvm is installed.
The matrix should now work thus:
1. qemu, qemu-system-x86_64, qemu-kvm all available
qemu+i686 => qemu
qemu+x86_64 => qemu-system-x86_64
kvm+i686 => qemu-kvm -cpu qemu32
kvm+x86_64 => qemu-kvm
2. qemu, qemu-kvm available
qemu+i686 => qemu
qemu+x86_64 => qemu-kvm -no-kvm
kvm+i686 => qemu-kvm -cpu qemu32
kvm+x86_64 => qemu-kvm
3. qemu-system-x86_64, qemu-kvm available
qemu+i686 => qemu-system-x86_64 -cpu qemu32
qemu+x86_64 => qemu-system-x86_64
kvm+i686 => qemu-kvm -cpu qemu32
kvm+x86_64 => qemu-kvm
4. qemu-kvm available
qemu+i686 => qemu-kvm -no-kvm -cpu qemu32
qemu+x86_64 => qemu-kvm -no-kvm
kvm+i686 => qemu-kvm -cpu qemu32
kvm+x86_64 => qemu-kvm
The only real remaining problem is that we don't cope with scenario
where the KVM enabled binary is called 'qemu-system-x64_64' instead
of 'qemu-kvm' or 'kvm'.
Regards,
Daniel
Index: src/qemu_conf.c
===================================================================
RCS file: /data/cvs/libvirt/src/qemu_conf.c,v
retrieving revision 1.138
diff -u -p -r1.138 qemu_conf.c
--- src/qemu_conf.c 16 Mar 2009 13:54:26 -0000 1.138
+++ src/qemu_conf.c 16 Mar 2009 17:53:20 -0000
@@ -211,6 +211,7 @@ struct qemu_arch_info {
const char *const *machines;
int nmachines;
const char *binary;
+ const char *altbinary;
const struct qemu_feature_flags *flags;
int nflags;
};
@@ -231,24 +232,24 @@ static const struct qemu_feature_flags c
/* The archicture tables for supported QEMU archs */
static const struct qemu_arch_info const arch_info_hvm[] = {
{ "i686", 32, arch_info_hvm_x86_machines, 2,
- "/usr/bin/qemu", arch_info_i686_flags, 4 },
+ "/usr/bin/qemu", "/usr/bin/qemu-system-x86_64",
arch_info_i686_flags, 4 },
{ "x86_64", 64, arch_info_hvm_x86_machines, 2,
- "/usr/bin/qemu-system-x86_64", arch_info_x86_64_flags, 2 },
+ "/usr/bin/qemu-system-x86_64", NULL, arch_info_x86_64_flags, 2 },
{ "mips", 32, arch_info_hvm_mips_machines, 1,
- "/usr/bin/qemu-system-mips", NULL, 0 },
+ "/usr/bin/qemu-system-mips", NULL, NULL, 0 },
{ "mipsel", 32, arch_info_hvm_mips_machines, 1,
- "/usr/bin/qemu-system-mipsel", NULL, 0 },
+ "/usr/bin/qemu-system-mipsel", NULL, NULL, 0 },
{ "sparc", 32, arch_info_hvm_sparc_machines, 1,
- "/usr/bin/qemu-system-sparc", NULL, 0 },
+ "/usr/bin/qemu-system-sparc", NULL, NULL, 0 },
{ "ppc", 32, arch_info_hvm_ppc_machines, 3,
- "/usr/bin/qemu-system-ppc", NULL, 0 },
+ "/usr/bin/qemu-system-ppc", NULL, NULL, 0 },
};
static const struct qemu_arch_info const arch_info_xen[] = {
{ "i686", 32, arch_info_xen_x86_machines, 1,
- "/usr/bin/xenner", arch_info_i686_flags, 4 },
+ "/usr/bin/xenner", NULL, arch_info_i686_flags, 4 },
{ "x86_64", 64, arch_info_xen_x86_machines, 1,
- "/usr/bin/xenner", arch_info_x86_64_flags, 2 },
+ "/usr/bin/xenner", NULL, arch_info_x86_64_flags, 2 },
};
static int
@@ -257,43 +258,62 @@ qemudCapsInitGuest(virCapsPtr caps,
const struct qemu_arch_info *info,
int hvm) {
virCapsGuestPtr guest;
- int i, haskvm, hasbase, samearch;
+ int i;
+ int hasbase = 0;
+ int hasaltbase = 0;
+ int haskvm = 0;
+ int haskqemu = 0;
const char *kvmbin = NULL;
- /* Check for existance of base emulator */
+ /* Check for existance of base emulator, or alternate base
+ * which can be used with magic cpu choice
+ */
hasbase = (access(info->binary, X_OK) == 0);
+ hasaltbase = (access(info->altbinary, X_OK) == 0);
- samearch = STREQ(info->arch, hostmachine);
- if (samearch) {
+ /* Can use acceleration for KVM/KQEMU if
+ * - host & guest arches match
+ * Or
+ * - hostarch is x86_64 and guest arch is i686
+ * The latter simply needs "-cpu qemu32"
+ */
+ if (STREQ(info->arch, hostmachine) ||
+ (STREQ(hostmachine, "x86_64") && STREQ(info->arch,
"i686"))) {
const char *const kvmbins[] = { "/usr/bin/qemu-kvm", /* Fedora */
"/usr/bin/kvm" }; /* Upstream .spec */
for (i = 0; i < ARRAY_CARDINALITY(kvmbins); ++i) {
- if ((haskvm = (access(kvmbins[i], X_OK) == 0))) {
+ if (access(kvmbins[i], X_OK) == 0 &&
+ access("/dev/kvm", F_OK) == 0) {
+ haskvm = 1;
kvmbin = kvmbins[i];
break;
}
}
- } else {
- haskvm = 0;
+
+ if (access("/dev/kqemu", F_OK) == 0)
+ haskqemu = 1;
}
- if (!hasbase && !haskvm)
+
+ if (!hasbase && !hasaltbase && !haskvm)
return 0;
+ /* We register kvm as the base emulator too, since we can
+ * just give -no-kvm to disable acceleration if required */
if ((guest = virCapabilitiesAddGuest(caps,
hvm ? "hvm" : "xen",
info->arch,
info->wordsize,
- info->binary,
+ (hasbase ? info->binary :
+ (hasaltbase ? info->altbinary : kvmbin)),
NULL,
info->nmachines,
info->machines)) == NULL)
return -1;
if (hvm) {
- if (hasbase &&
- virCapabilitiesAddGuestDomain(guest,
+ if (virCapabilitiesAddGuestDomain(guest,
"qemu",
NULL,
NULL,
@@ -301,27 +321,23 @@ qemudCapsInitGuest(virCapsPtr caps,
NULL) == NULL)
return -1;
- /* If guest & host match, then we can accelerate */
- if (samearch) {
- if (access("/dev/kqemu", F_OK) == 0 &&
- virCapabilitiesAddGuestDomain(guest,
- "kqemu",
- NULL,
- NULL,
- 0,
- NULL) == NULL)
- return -1;
+ if (haskqemu &&
+ virCapabilitiesAddGuestDomain(guest,
+ "kqemu",
+ NULL,
+ NULL,
+ 0,
+ NULL) == NULL)
+ return -1;
- if (access("/dev/kvm", F_OK) == 0 &&
- haskvm &&
- virCapabilitiesAddGuestDomain(guest,
- "kvm",
- kvmbin,
- NULL,
- 0,
- NULL) == NULL)
- return -1;
- }
+ if (haskvm &&
+ virCapabilitiesAddGuestDomain(guest,
+ "kvm",
+ kvmbin,
+ NULL,
+ 0,
+ NULL) == NULL)
+ return -1;
} else {
if (virCapabilitiesAddGuestDomain(guest,
"kvm",
@@ -363,12 +379,14 @@ virCapsPtr qemudCapsInit(void) {
if (virCapsInitNUMA(caps) < 0)
goto no_memory;
+ /* First the pure HVM guests */
for (i = 0 ; i < ARRAY_CARDINALITY(arch_info_hvm) ; i++)
if (qemudCapsInitGuest(caps,
utsname.machine,
&arch_info_hvm[i], 1) < 0)
goto no_memory;
+ /* Then possibly the Xen paravirt guests (ie Xenner */
if (access("/usr/bin/xenner", X_OK) == 0 &&
access("/dev/kvm", F_OK) == 0) {
for (i = 0 ; i < ARRAY_CARDINALITY(arch_info_xen) ; i++)
@@ -430,6 +448,8 @@ int qemudExtractVersionInfo(const char *
if (strstr(help, "-no-kqemu"))
flags |= QEMUD_CMD_FLAG_KQEMU;
+ if (strstr(help, "-no-kvm"))
+ flags |= QEMUD_CMD_FLAG_KVM;
if (strstr(help, "-no-reboot"))
flags |= QEMUD_CMD_FLAG_NO_REBOOT;
if (strstr(help, "-name"))
@@ -749,6 +769,7 @@ int qemudBuildCommandLine(virConnectPtr
char boot[VIR_DOMAIN_BOOT_LAST];
struct utsname ut;
int disableKQEMU = 0;
+ int disableKVM = 0;
int qargc = 0, qarga = 0;
const char **qargv = NULL;
int qenvc = 0, qenva = 0;
@@ -757,6 +778,7 @@ int qemudBuildCommandLine(virConnectPtr
char uuid[VIR_UUID_STRING_BUFLEN];
char domid[50];
char *pidfile;
+ const char *cpu = NULL;
uname_normalize(&ut);
@@ -789,9 +811,16 @@ int qemudBuildCommandLine(virConnectPtr
}
}
+ emulator = vm->def->emulator;
+ if (!emulator)
+ emulator = virDomainDefDefaultEmulator(conn, vm->def, driver->caps);
+ if (!emulator)
+ return -1;
+
+
/* Need to explicitly disable KQEMU if
* 1. Arch matches host arch
- * 2. Guest is 'qemu'
+ * 2. Guest domain is 'qemu'
* 3. The qemu binary has the -no-kqemu flag
*/
if ((qemuCmdFlags & QEMUD_CMD_FLAG_KQEMU) &&
@@ -799,6 +828,34 @@ int qemudBuildCommandLine(virConnectPtr
vm->def->virtType == VIR_DOMAIN_VIRT_QEMU)
disableKQEMU = 1;
+ /* Need to explicitly disable KVM if
+ * 1. Arch matches host arch
+ * 2. Guest domain is 'qemu'
+ * 3. The qemu binary has the -no-kvm flag
+ */
+ if ((qemuCmdFlags & QEMUD_CMD_FLAG_KVM) &&
+ STREQ(ut.machine, vm->def->os.arch) &&
+ vm->def->virtType == VIR_DOMAIN_VIRT_QEMU)
+ disableKVM = 1;
+
+ /*
+ * Need to force a 32-bit guest CPU type if
+ *
+ * 1. guest OS is i686
+ * 2. host OS is x86_64
+ * 3. emulator is qemu-kvm or kvm
+ *
+ * Or
+ *
+ * 1. guest OS is i686
+ * 2. emulator is qemu-system-x86_64
+ */
+ if (STREQ(vm->def->os.arch, "i686") &&
+ ((STREQ(ut.machine, "x86_64") &&
+ strstr(emulator, "kvm")) ||
+ strstr(emulator, "x86_64")))
+ cpu = "qemu32";
+
#define ADD_ARG_SPACE \
do { \
if (qargc == qarga) { \
@@ -887,12 +944,6 @@ int qemudBuildCommandLine(virConnectPtr
ADD_ENV_COPY("LOGNAME");
ADD_ENV_COPY("TMPDIR");
- emulator = vm->def->emulator;
- if (!emulator)
- emulator = virDomainDefDefaultEmulator(conn, vm->def, driver->caps);
- if (!emulator)
- return -1;
-
ADD_ARG_LIT(emulator);
ADD_ARG_LIT("-S");
@@ -904,9 +955,15 @@ int qemudBuildCommandLine(virConnectPtr
ADD_ARG_LIT("-M");
ADD_ARG_LIT(vm->def->os.machine);
}
+ if (cpu) {
+ ADD_ARG_LIT("-cpu");
+ ADD_ARG_LIT(cpu);
+ }
if (disableKQEMU)
ADD_ARG_LIT("-no-kqemu");
+ if (disableKVM)
+ ADD_ARG_LIT("-no-kvm");
ADD_ARG_LIT("-m");
ADD_ARG_LIT(memory);
ADD_ARG_LIT("-smp");
Index: src/qemu_conf.h
===================================================================
RCS file: /data/cvs/libvirt/src/qemu_conf.h,v
retrieving revision 1.58
diff -u -p -r1.58 qemu_conf.h
--- src/qemu_conf.h 16 Mar 2009 13:54:26 -0000 1.58
+++ src/qemu_conf.h 16 Mar 2009 17:53:20 -0000
@@ -55,6 +55,7 @@ enum qemud_cmd_flags {
QEMUD_CMD_FLAG_MIGRATE_QEMU_TCP = (1 << 10), /* New migration syntax after
merge to QEMU with TCP transport */
QEMUD_CMD_FLAG_MIGRATE_QEMU_EXEC = (1 << 11), /* New migration syntax after
merge to QEMU with EXEC transport */
QEMUD_CMD_FLAG_DRIVE_CACHE_V2 = (1 << 12), /* Is the cache= flag wanting new
v2 values */
+ QEMUD_CMD_FLAG_KVM = (1 << 13), /* Whether KVM is compiled in */
};
/* Main driver state */
Index: src/qemu_driver.c
===================================================================
RCS file: /data/cvs/libvirt/src/qemu_driver.c,v
retrieving revision 1.218
diff -u -p -r1.218 qemu_driver.c
--- src/qemu_driver.c 16 Mar 2009 17:16:04 -0000 1.218
+++ src/qemu_driver.c 16 Mar 2009 17:53:20 -0000
@@ -1733,6 +1733,7 @@ qemudMonitorCommand(const virDomainObjPt
static int qemudProbe(void)
{
if ((virFileExists("/usr/bin/qemu")) ||
+ (virFileExists("/usr/bin/qemu-system-x86_64")) ||
(virFileExists("/usr/bin/qemu-kvm")) ||
(virFileExists("/usr/bin/kvm")) ||
(virFileExists("/usr/bin/xenner")))
@@ -1749,10 +1750,10 @@ static virDrvOpenStatus qemudOpen(virCon
if (qemu_driver == NULL)
goto decline;
- if (!qemudProbe())
- goto decline;
-
if (conn->uri == NULL) {
+ if (!qemudProbe())
+ goto decline;
+
conn->uri = xmlParseURI(uid ? "qemu:///session" :
"qemu:///system");
if (!conn->uri) {
virReportOOMError(conn);
--
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