[kvm-unit-tests PATCH v3 0/2] s390x: dump support for PV tests

[kvm-unit-tests PATCH v3 0/2] s390x: dump support for PV tests

[Nico Boehr]

v2->v3:
---
- add some comments and newlines (thanks Janosch)

v1->v2:
---
- add newline after genprotimg_args (thanks Janosch)
- add a comment explaining what the CCK is (thanks Janosch)

With the upcoming possibility to dump PV guests under s390x, we should
be able to dump kvm-unit-tests for debugging, too.

Add the necessary flags to genprotimg to allow dumping.

Nico Boehr (2):
  s390x: factor out common args for genprotimg
  s390x: create persistent comm-key

 s390x/Makefile | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

-- 
2.36.1

[kvm-unit-tests PATCH v3 1/2] s390x: factor out common args for genprotimg

[Nico Boehr]

Upcoming changes will add more arguments to genprotimg. To avoid
duplicating this logic, move the arguments to genprotimg to a variable.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 s390x/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/s390x/Makefile b/s390x/Makefile
index efd5e0c13102..d17055ebe6a8 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -165,11 +165,13 @@ $(SNIPPET_DIR)/c/%.hdr: $(SNIPPET_DIR)/c/%.gbin $(HOST_KEY_DOCUMENT)
 %.bin: %.elf
 	$(OBJCOPY) -O binary  $< $@
 
+genprotimg_args = --host-key-document $(HOST_KEY_DOCUMENT) --no-verify
+
 %selftest.pv.bin: %selftest.bin $(HOST_KEY_DOCUMENT) $(patsubst %.pv.bin,%.parmfile,$@)
-	$(GENPROTIMG) --host-key-document $(HOST_KEY_DOCUMENT) --parmfile $(patsubst %.pv.bin,%.parmfile,$@) --no-verify --image $< -o $@
+	$(GENPROTIMG) $(genprotimg_args) --parmfile $(patsubst %.pv.bin,%.parmfile,$@) --image $< -o $@
 
 %.pv.bin: %.bin $(HOST_KEY_DOCUMENT)
-	$(GENPROTIMG) --host-key-document $(HOST_KEY_DOCUMENT) --no-verify --image $< -o $@
+	$(GENPROTIMG) $(genprotimg_args) --image $< -o $@
 
 $(snippet_asmlib): $$(patsubst %.o,%.S,$$@) $(asm-offsets)
 	$(CC) $(CFLAGS) -c -nostdlib -o $@ $<
-- 
2.36.1

[kvm-unit-tests PATCH v3 2/2] s390x: create persistent comm-key

[Nico Boehr]

To decrypt the dump of a PV guest, the comm-key (CCK) is required. Until
now, no comm-key was provided to genprotimg, therefore decrypting the
dump of a kvm-unit-test under PV was not possible.

This patch makes sure that we create a random CCK if there's no
$(TEST_DIR)/comm.key file.

Also allow dumping of PV tests by passing the appropriate PCF to
genprotimg (bit 34). --x-pcf is used to be compatible with older
genprotimg versions, which don't support --enable-dump. 0xe0 is the
default PCF value and only bit 34 is added.

Unfortunately, recent versions of genprotimg removed the --x-comm-key
argument which was used by older versions to specify the CCK. To support
these versions, we need to parse the genprotimg help output and decide
which argument to use.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 s390x/Makefile | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/s390x/Makefile b/s390x/Makefile
index d17055ebe6a8..d1a7bf6004a1 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -162,15 +162,33 @@ $(SNIPPET_DIR)/c/%.hdr: $(SNIPPET_DIR)/c/%.gbin $(HOST_KEY_DOCUMENT)
 	$(RM) $(@:.elf=.aux.o)
 	@chmod a-x $@
 
+# Secure Execution Customer Communication Key file
+# 32 bytes of key material, uses existing one if available
+comm-key = $(TEST_DIR)/comm.key
+$(comm-key):
+	dd if=/dev/urandom of=$@ bs=32 count=1 status=none
+
 %.bin: %.elf
 	$(OBJCOPY) -O binary  $< $@
 
-genprotimg_args = --host-key-document $(HOST_KEY_DOCUMENT) --no-verify
+# The genprotimg arguments for the cck changed over time so we need to
+# figure out which argument to use in order to set the cck
+GENPROTIMG_HAS_COMM_KEY = $(shell $(GENPROTIMG) --help | grep -q -- --comm-key && echo yes)
+ifeq ($(GENPROTIMG_HAS_COMM_KEY),yes)
+	GENPROTIMG_COMM_KEY = --comm-key $(comm-key)
+else
+	GENPROTIMG_COMM_KEY = --x-comm-key $(comm-key)
+endif
+
+# use x-pcf to be compatible with old genprotimg versions
+# allow dumping + PCKMO
+genprotimg_pcf = 0x200000e0
+genprotimg_args = --host-key-document $(HOST_KEY_DOCUMENT) --no-verify $(GENPROTIMG_COMM_KEY) --x-pcf $(genprotimg_pcf)
 
-%selftest.pv.bin: %selftest.bin $(HOST_KEY_DOCUMENT) $(patsubst %.pv.bin,%.parmfile,$@)
+%selftest.pv.bin: %selftest.bin $(HOST_KEY_DOCUMENT) $(patsubst %.pv.bin,%.parmfile,$@) $(comm-key)
 	$(GENPROTIMG) $(genprotimg_args) --parmfile $(patsubst %.pv.bin,%.parmfile,$@) --image $< -o $@
 
-%.pv.bin: %.bin $(HOST_KEY_DOCUMENT)
+%.pv.bin: %.bin $(HOST_KEY_DOCUMENT) $(comm-key)
 	$(GENPROTIMG) $(genprotimg_args) --image $< -o $@
 
 $(snippet_asmlib): $$(patsubst %.o,%.S,$$@) $(asm-offsets)
@@ -178,7 +196,7 @@ $(snippet_asmlib): $$(patsubst %.o,%.S,$$@) $(asm-offsets)
 
 
 arch_clean: asm_offsets_clean
-	$(RM) $(TEST_DIR)/*.{o,elf,bin} $(SNIPPET_DIR)/*/*.{o,elf,*bin,*obj,hdr} $(SNIPPET_DIR)/asm/.*.d $(TEST_DIR)/.*.d lib/s390x/.*.d
+	$(RM) $(TEST_DIR)/*.{o,elf,bin} $(SNIPPET_DIR)/*/*.{o,elf,*bin,*obj,hdr} $(SNIPPET_DIR)/asm/.*.d $(TEST_DIR)/.*.d lib/s390x/.*.d $(comm-key)
 
 generated-files = $(asm-offsets)
 $(tests:.elf=.o) $(asmlib) $(cflatobjs): $(generated-files)
-- 
2.36.1

Re: [kvm-unit-tests PATCH v3 2/2] s390x: create persistent comm-key

[Janosch Frank]

On 9/9/22 14:14, Nico Boehr wrote:
> To decrypt the dump of a PV guest, the comm-key (CCK) is required. Until
> now, no comm-key was provided to genprotimg, therefore decrypting the
> dump of a kvm-unit-test under PV was not possible.
> 
> This patch makes sure that we create a random CCK if there's no
> $(TEST_DIR)/comm.key file.
> 
> Also allow dumping of PV tests by passing the appropriate PCF to
> genprotimg (bit 34). --x-pcf is used to be compatible with older
> genprotimg versions, which don't support --enable-dump. 0xe0 is the
> default PCF value and only bit 34 is added.
> 
> Unfortunately, recent versions of genprotimg removed the --x-comm-key
> argument which was used by older versions to specify the CCK. To support
> these versions, we need to parse the genprotimg help output and decide
> which argument to use.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

Re: [kvm-unit-tests PATCH v3 0/2] s390x: dump support for PV tests

[Janosch Frank]

On 9/9/22 14:14, Nico Boehr wrote:
> v2->v3:
> ---
> - add some comments and newlines (thanks Janosch)
> 
> v1->v2:
> ---
> - add newline after genprotimg_args (thanks Janosch)
> - add a comment explaining what the CCK is (thanks Janosch)
> 
> With the upcoming possibility to dump PV guests under s390x, we should
> be able to dump kvm-unit-tests for debugging, too.
> 
> Add the necessary flags to genprotimg to allow dumping.
> 
> Nico Boehr (2):
>    s390x: factor out common args for genprotimg
>    s390x: create persistent comm-key
> 
>   s390x/Makefile | 30 +++++++++++++++++++++++++-----
>   1 file changed, 25 insertions(+), 5 deletions(-)
> 

Thanks, picked