[kvm-unit-tests PATCH v2 1/1] s390x: do not enable PV dump support by default

[Nico Boehr <nrb@linux.ibm.com>]

Currently, dump support is always enabled by setting the respective
plaintext control flag (PCF). Unfortunately, older machines without
support for PV dump will not start the guest when this PCF is set. This
will result in an error message like this:

qemu-system-s390x: KVM PV command 2 (KVM_PV_SET_SEC_PARMS) failed: header rc 106 rrc 0 IOCTL rc: -22

Hence, by default, disable dump support to preserve compatibility with
older machines. Users can enable dumping support by passing
--enable-dump to the configure script.

Fixes: 3043685825d9 ("s390x: create persistent comm-key")
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 configure      | 11 +++++++++++
 s390x/Makefile | 26 +++++++++++++++++---------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/configure b/configure
index 5b7daac3c6e8..b81f20942c9c 100755
--- a/configure
+++ b/configure
@@ -28,6 +28,7 @@ errata_force=0
 erratatxt="$srcdir/errata.txt"
 host_key_document=
 gen_se_header=
+enable_dump=no
 page_size=
 earlycon=
 efi=
@@ -67,6 +68,9 @@ usage() {
 	    --gen-se-header=GEN_SE_HEADER
 	                           Provide an executable to generate a PV header
 	                           requires --host-key-document. (s390x-snippets only)
+	    --[enable|disable]-dump
+	                           Allow PV guests to be dumped. Requires at least z16.
+	                           (s390x only)
 	    --page-size=PAGE_SIZE
 	                           Specify the page size (translation granule) (4k, 16k or
 	                           64k, default is 64k, arm64 only)
@@ -146,6 +150,12 @@ while [[ "$1" = -* ]]; do
 	--gen-se-header)
 	    gen_se_header="$arg"
 	    ;;
+	--enable-dump)
+	    enable_dump=yes
+	    ;;
+	--disable-dump)
+	    enable_dump=no
+	    ;;
 	--page-size)
 	    page_size="$arg"
 	    ;;
@@ -387,6 +397,7 @@ U32_LONG_FMT=$u32_long
 WA_DIVIDE=$wa_divide
 GENPROTIMG=${GENPROTIMG-genprotimg}
 HOST_KEY_DOCUMENT=$host_key_document
+CONFIG_DUMP=$enable_dump
 CONFIG_EFI=$efi
 CONFIG_WERROR=$werror
 GEN_SE_HEADER=$gen_se_header
diff --git a/s390x/Makefile b/s390x/Makefile
index 649486f2d4a0..271b6803a1c5 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -173,18 +173,26 @@ $(comm-key):
 %.bin: %.elf
 	$(OBJCOPY) -O binary  $< $@
 
-# 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 $(comm-key)
+# Will only be filled when dump has been enabled
+GENPROTIMG_COMM_KEY =
+# allow PCKMO
+genprotimg_pcf = 0x000000e0
+
+ifeq ($(CONFIG_DUMP),yes)
+	# 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
+
+	# allow dumping + PCKMO
+	genprotimg_pcf = 0x200000e0
 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) $(patsubst %.pv.bin,%.parmfile,$@) $(comm-key)
-- 
2.36.1