On Mon, 2021-02-08 at 17:30 -0700, Jim Fehlig wrote: > Hi All, > > I received a private bug report that starting a VM with swtpm device fails with > qemu-system-aarch64. The VM config has > > <tpm model='tpm-tis'> > <backend type='emulator' version='2.0'/> > </tpm> > > QEMU reports the following error > > error: internal error: process exited while connecting to monitor: > 2021-02-07T05:15:35.378927Z qemu-system-aarch64: -device > tpm-tis,tpmdev=tpm-tpm0,id=tpm0: 'tpm-tis' is not a valid device model name > > Indeed it appears the device name is 'tpm-tis-device' [1][2] for ARM virt. The > similar yet different device naming between x86 and ARM is unfortunate. IIUC, > the devices are the same between the architectures, i.e. they both emulate a TPM > device conforming to the TIS spec. If so, adding a 'tpm-tis-device' to > virDomainTPMModel seems redundant. I assume the naming difference should be > handled internally, e.g. something like the below patch to qemuBuildTPMDevStr? I > can send a proper patch if this is an acceptable approach. > > Regards, > Jim > > [1] https://qemu.readthedocs.io/en/latest/specs/tpm.html > [2] https://github.com/qemu/qemu/commit/c294ac327ca99342b90bd3a83d2cef9b447afaa7 > > diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c > index 92036d26c0..5154611ccd 100644 > --- a/src/qemu/qemu_command.c > +++ b/src/qemu/qemu_command.c > @@ -9198,6 +9198,9 @@ qemuBuildTPMDevStr(const virDomainDef *def, > g_auto(virBuffer) buf = VIR_BUFFER_INITIALIZER; > const char *model = virDomainTPMModelTypeToString(tpm->model); > > + if (tpm->model == VIR_DOMAIN_TPM_MODEL_TIS && def->os.arch == VIR_ARCH_AARCH64) > + model = "tpm-tis-device"; > + > virBufferAsprintf(&buf, "%s,tpmdev=tpm-%s,id=%s", > model, tpm->info.alias, tpm->info.alias); > This looks fairly reasonable. Please make sure you also include a test case for this usage.

If you're feeling fancy, you might consider augmenting qemuValidateDomainDeviceDefTPM() to ensure VIR_DOMAIN_TPM_MODEL_TIS is only used on x86 or with the aarch64 virt machine type.