Re: What is TYPE_TPM_TIS_ISA? (Not an ISA Device)

[Stefan Berger <stefanb@linux.ibm.com>]

On 7/22/20 1:55 AM, Markus Armbruster wrote:
> pm socket --tpmstate dir=tpm --ctrl type=unixio,path=tpm/swtpm-soc
> running in another terminal.
>
>>> 3/ no machine plug it using isa_register_ioport()
>>>     (it is not registered to the ISA memory space)
>> There's no requirement for an ISA device to have IO ports...
>>
>> thanks
>> -- PMM
> Thread hijack!  Since I didn't have swtpm installed, I tried to take a
> shortcut:
>
>      $ qemu-system-x86_64 -nodefaults -S -display none -monitor stdio -chardev null,id=tpm0 -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
>      qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: tpm-emulator: tpm chardev 'chrtpm' not found.
>      qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: tpm-emulator: Could not cleanly shutdown the TPM: No such file or directory
>      QEMU 5.0.90 monitor - type 'help' for more information
>      (qemu) qemu-system-x86_64: -device tpm-tis,tpmdev=tpm0: Property 'tpm-tis.tpmdev' can't find value 'tpm0'
>      $ echo $?
>      1
>
> That a null chardev doesn't work is fine.  But the error handling looks
> broken: QEMU diagnoses and reports the problem, then continues.  The
> final error message indicates that it continued without creating the
> backend "tpm0".  That's wrong.


This issue can be solve via the following change that then displays this 
error:

$ x86_64-softmmu/qemu-system-x86_64 -nodefaults -S -display none 
-monitor stdio -chardev null,id=tpm0 -tpmdev 
emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0
qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: 
tpm-emulator: tpm chardev 'chrtpm' not found.
qemu-system-x86_64: -tpmdev emulator,id=tpm0,chardev=chrtpm: 
tpm-emulator: Could not cleanly shutdown the TPM: No such file or directory


diff --git a/tpm.c b/tpm.c
index 358566cb10..857a861e69 100644
--- a/tpm.c
+++ b/tpm.c
@@ -170,8 +170,10 @@ void tpm_cleanup(void)
   */
  void tpm_init(void)
  {
-    qemu_opts_foreach(qemu_find_opts("tpmdev"),
-                      tpm_init_tpmdev, NULL, &error_fatal);
+    if (qemu_opts_foreach(qemu_find_opts("tpmdev"),
+                          tpm_init_tpmdev, NULL, &error_fatal)) {
+        exit(1);
+    }
  }

  /*

We had something like this before this patch here was applied: 
https://github.com/qemu/qemu/commit/d10e05f15d5c3dd5e5cc59c5dfff460d89d48580#diff-0ec5df49c6751cb2dc9fa18ed5cf9f0e


Do we now want to partially revert this patch or call the exit(1) as 
shown here?


    Stefan