[libvirt] [PATCH 3/6] qemu: Drop disabled CPU features unknown to QEMU

When a CPU definition wants to explicitly disable some features that are unknown to QEMU, we can safely drop them from the definition before starting QEMU. Naturally QEMU won't enable such features implicitly. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/qemu/qemu_process.c | 32 +++++++++++++++++++ ...-Icelake-Server-pconfig.x86_64-latest.args | 2 +- 2 files changed, 33 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index ed8666e9d1..06c9eba16c 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -6068,6 +6068,26 @@ qemuProcessSetupHotpluggableVcpus(virQEMUDriverPtr driver, } +static bool +qemuProcessDropUnknownCPUFeatures(const char *name, + virCPUFeaturePolicy policy, + void *opaque) +{ + const char **features = opaque; + + if (policy != VIR_CPU_FEATURE_DISABLE && + policy != VIR_CPU_FEATURE_FORBID) + return true; + + if (virStringListHasString(features, name)) + return true; + + /* Features unknown to QEMU are implicitly disabled, we can just drop them + * from the definition. */ + return false; +} + + static int qemuProcessUpdateGuestCPU(virDomainDefPtr def, virQEMUCapsPtr qemuCaps, @@ -6133,6 +6153,18 @@ qemuProcessUpdateGuestCPU(virDomainDefPtr def, &def->os.arch) < 0) return -1; + if (ARCH_IS_X86(def->os.arch)) { + VIR_AUTOSTRINGLIST features = NULL; + + if (virQEMUCapsGetCPUFeatures(qemuCaps, def->virtType, false, &features) < 0) + return -1; + + if (features && + virCPUDefFilterFeatures(def->cpu, qemuProcessDropUnknownCPUFeatures, + features) < 0) + return -1; + } + return 0; } diff --git a/tests/qemuxml2argvdata/cpu-Icelake-Server-pconfig.x86_64-latest.args b/tests/qemuxml2argvdata/cpu-Icelake-Server-pconfig.x86_64-latest.args index d6f5a0ad98..88d05a482a 100644 --- a/tests/qemuxml2argvdata/cpu-Icelake-Server-pconfig.x86_64-latest.args +++ b/tests/qemuxml2argvdata/cpu-Icelake-Server-pconfig.x86_64-latest.args @@ -13,7 +13,7 @@ QEMU_AUDIO_DRV=none \ -object secret,id=masterKey0,format=raw,\ file=/tmp/lib/domain--1-test/master-key.aes \ -machine pc,accel=kvm,usb=off,dump-guest-core=off \ --cpu Icelake-Server,pconfig=off \ +-cpu Icelake-Server \ -m 214 \ -overcommit mem-lock=off \ -smp 1,sockets=1,cores=1,threads=1 \ -- 2.24.0