qemu: Forbid MSR features with old QEMU

Without "unavailable-features" CPU property we cannot properly detect
whether a specific MSR feature we asked for (either explicitly or
implicitly via a CPU model) was disabled by QEMU for some reason.
Because this could break migration, snapshots, and save/restore
operaions, it's better to just forbid any use of MSR features with QEMU
which lacks "unavailable-features" CPU property.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This commit is contained in:
Jiri Denemark 2019-06-19 21:59:49 +02:00
parent c8ec678fd9
commit 8eb4a89f5f

View File

@ -59,6 +59,7 @@
#include "qemu_firmware.h"
#include "cpu/cpu.h"
#include "cpu/cpu_x86.h"
#include "datatypes.h"
#include "virlog.h"
#include "virerror.h"
@ -5406,9 +5407,32 @@ qemuProcessStartValidate(virQEMUDriverPtr driver,
if (qemuProcessStartValidateShmem(vm) < 0)
return -1;
if (vm->def->cpu &&
virCPUValidateFeatures(vm->def->os.arch, vm->def->cpu) < 0)
return -1;
if (vm->def->cpu) {
if (virCPUValidateFeatures(vm->def->os.arch, vm->def->cpu) < 0)
return -1;
if (ARCH_IS_X86(vm->def->os.arch) &&
!virQEMUCapsGet(qemuCaps, QEMU_CAPS_CPU_UNAVAILABLE_FEATURES)) {
VIR_AUTOSTRINGLIST features = NULL;
int n;
if ((n = virCPUDefCheckFeatures(vm->def->cpu,
virCPUx86FeatureFilterSelectMSR,
NULL,
&features)) < 0)
return -1;
if (n > 0) {
VIR_AUTOFREE(char *) str = NULL;
str = virStringListJoin((const char **)features, ", ");
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("Some features cannot be reliably used "
"with this QEMU: %s"), str);
return -1;
}
}
}
if (qemuProcessStartValidateDisks(vm, qemuCaps) < 0)
return -1;