[V23,4/7] Build the TPM frontend code

Message ID 51200303.7010005@linux.vnet.ibm.com
State New
Headers show

Commit Message

Stefan Berger Feb. 16, 2013, 10:06 p.m.
On 02/16/2013 06:19 AM, Andreas Färber wrote:
> @@ -1 +1,2 @@
>   common-obj-y = tpm.o
> +common-obj-$(CONFIG_TPM) += tpm_tis.o
> Some softmmus might not even support ISA, so this needs to be
> conditional on more than just the host's $(CONFIG_TPM), it should be a
> combination of the host's CONFIG_TPM=y and CONFIG_TPM_TIS=y in
> default-configs/{i386,x86_64}-softmmu.config or similar.

I am having some tough problems here getting the above suggestion 
implemented and building for example for i386 and x86_64 while not 
building TPM for other targets. as Andreas suggested, ISA may not be 
available or TPM may not be typically available. The problems I am 
facing are related to CONFIG_TPM and CONFIG_TPM_PASSTHROUGH being used 
in vl.c and qemu-options.hx and for example vl.c #include'ing 
config-host.h, which then gives it access to those #defines.

from qemu-options.hx

  #ifdef CONFIG_TPM
  DEFHEADING(TPM device options:)

  DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
-    "-tpmdev [<type>],id=str[,option][,option][,...]\n",
+    "-tpmdev passthrough,id=id[,path=path]\n"
+    "                use path to provide path to a character device; default is /dev/tpm0\n",

I believe the above makes sense. It only shows the -tpmdev passthrough option as being available if in fact the passthrough device has been compiled in. CONFIG_TPM and CONFIG_TPM_PASSTHROUGH are created through ./configure --enable-tpm and --enable-tpm-passthrough respectively and end up in config-host.h. Config-host.h is not a problem to include in qemu-options.hx and also not in vl.c:

The following is from vl.c where we restrict the -tpmdev option to only be available if the TPM passthrough was compiled in. The restriction with the #define's is necessary due to similar restrictions in qemu-options.hx.

  #ifdef CONFIG_TPM
              case QEMU_OPTION_tpmdev:
                  if (tpm_config_parse(qemu_find_opts("tpmdev"), optarg) < 0) {
+# endif

I have tried to make CONFIG_TPM and CONFIG_TPM_PASSTHROUGH target-specific #defines by having them written for example into i386-softmmu/config-target.h. Once I do that I get problems #includ'ing the config-target.h from vl.c for example. Vl.c does not see the necessary -include path to config-target.h via gcc as for example exec.c sees it. So it's not compileable this way and I would have to have vl.c built as part of obj-y rather than common-obj-y.

Even though soundhw may not be considered a good model to follow, the following patch allows me to build for different architectures and simply disable the usage of the TPM by reducing the choices the user has:

  Makefile.objs     |    1 +
  configure         |    8 ++++++++
  tpm/Makefile.objs |    2 +-
  3 files changed, 10 insertions(+), 1 deletion(-)

tpm/tpm.o has to be built as part of obj-y to 'see' -DHAS_TPM_CHOICE. 
This is similar to arch_init.o being built as part of obj-y to see 

I have now been wrestling with this challenge for a couple of hours. 
Please let me know how to go about it. I tried several paths but some 
end up with above mentioned compilation problems.

Thanks and regards,


Index: qemu-git.pt/configure
--- qemu-git.pt.orig/configure
+++ qemu-git.pt/configure
@@ -4279,6 +4279,14 @@  if test "$tpm" = "yes"; then
+if test "$target_softmmu" = "yes" ; then
+  case "$TARGET_BASE_ARCH" in
+  i386|x86_64)
+    cflags="-DHAS_TPM_CHOICE $cflags"
+  ;;
+  esac
  if test "$ARCH" = "tci"; then
Index: qemu-git.pt/tpm/Makefile.objs
--- qemu-git.pt.orig/tpm/Makefile.objs
+++ qemu-git.pt/tpm/Makefile.objs
@@ -1,3 +1,3 @@ 
-common-obj-y = tpm.o
+obj-y = tpm.o
  common-obj-$(CONFIG_TPM) += tpm_tis.o tpm_backend.o
  common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o
Index: qemu-git.pt/Makefile.objs
--- qemu-git.pt.orig/Makefile.objs
+++ qemu-git.pt/Makefile.objs
@@ -75,6 +75,7 @@  common-obj-y += dma-helpers.o
  common-obj-y += qtest.o
  common-obj-y += vl.o
  common-obj-y += tpm/
+obj-y += tpm/
  common-obj-$(CONFIG_SLIRP) += slirp/