[v1] pvshim: make PV shim build selectable from configure

[Xen-devel] [PATCH] pvshim: make PV shim build selectable from configure

Posted by Roger Pau Monne 4 years, 11 months ago

So a user can decide whether to compile a PV shim as part of the tools
build. Note that the default behavior is preserved, which is to build a
PV shim when the target architecture is x86.

Requested-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
NOTE: run autogen.sh after applying.
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---
 config/Tools.mk.in      |  2 ++
 tools/configure.ac      | 12 ++++++++++++
 tools/firmware/Makefile |  4 ----
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/config/Tools.mk.in b/config/Tools.mk.in
index 98245f63c9..84ddb1a542 100644
--- a/config/Tools.mk.in
+++ b/config/Tools.mk.in
@@ -75,3 +75,5 @@ TINFO_LIBS          := @TINFO_LIBS@
 ARGP_LDFLAGS        := @argp_ldflags@
 
 FILE_OFFSET_BITS    := @FILE_OFFSET_BITS@
+
+CONFIG_PV_SHIM      := @pvshim@
diff --git a/tools/configure.ac b/tools/configure.ac
index c9fd69ddfa..2d2f657cac 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -492,4 +492,16 @@ AC_ARG_ENABLE([9pfs],
 
 AC_SUBST(ninepfs)
 
+AC_ARG_ENABLE([pvshim],
+    AS_HELP_STRING([--disable-pvshim],
+                   [Disable pvshim build (x86 only, enabled by default)]),
+    [AS_IF([test "x$enable_pvshim" = "xno"], [pvshim=n], [pvshim=y])], [
+    case "$target_cpu" in
+        i[[3456]]86|x86_64)
+           pvshim="y";;
+        *) pvshim="n";;
+    esac
+])
+AC_SUBST(pvshim)
+
 AC_OUTPUT()
diff --git a/tools/firmware/Makefile b/tools/firmware/Makefile
index cf304fc578..809a5fd025 100644
--- a/tools/firmware/Makefile
+++ b/tools/firmware/Makefile
@@ -1,10 +1,6 @@
 XEN_ROOT = $(CURDIR)/../..
 include $(XEN_ROOT)/tools/Rules.mk
 
-ifneq ($(XEN_TARGET_ARCH),x86_32)
-CONFIG_PV_SHIM := y
-endif
-
 # hvmloader is a 32-bit protected mode binary.
 TARGET      := hvmloader/hvmloader
 INST_DIR := $(DESTDIR)$(XENFIRMWAREDIR)
-- 
2.17.2 (Apple Git-113)


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Re: [Xen-devel] [PATCH] pvshim: make PV shim build selectable from configure

Posted by Jan Beulich 4 years, 11 months ago

>>> On 14.05.19 at 13:17, <roger.pau@citrix.com> wrote:
> So a user can decide whether to compile a PV shim as part of the tools
> build. Note that the default behavior is preserved, which is to build a
> PV shim when the target architecture is x86.

But the original behavior was so only when building x86_64 - see
the three lines you remove from tools/firmware/Makefile.

> --- a/tools/configure.ac
> +++ b/tools/configure.ac
> @@ -492,4 +492,16 @@ AC_ARG_ENABLE([9pfs],
>  
>  AC_SUBST(ninepfs)
>  
> +AC_ARG_ENABLE([pvshim],
> +    AS_HELP_STRING([--disable-pvshim],
> +                   [Disable pvshim build (x86 only, enabled by default)]),
> +    [AS_IF([test "x$enable_pvshim" = "xno"], [pvshim=n], [pvshim=y])], [
> +    case "$target_cpu" in
> +        i[[3456]]86|x86_64)
> +           pvshim="y";;

As said in the earlier discussion - at least gcc-based tool chains
are unlikely to cope when on ix86. Together with the changed
default behavior I guess you're actively breaking the (32-bit
x86) build. At the very least you'd need to probe for a capable
(cross) tool chain. (Quite possibly a 32-bit build on a 64-bit
host would still work fine, but that's not enough imo.)

Jan

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