Deprecate 32 bit big-endian MIPS

It's becoming harder to maintain a cross-compiler to test this host
architecture as the old stable Debian 10 ("Buster") moved into LTS
which supports fewer architectures. For now:

  - mark it's deprecation in the docs
  - downgrade the containers to build TCG tests only
  - drop the cross builds from our CI

Users with an appropriate toolchain and user-space can still take
their chances building it.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220914155950.804707-22-alex.bennee@linaro.org>

.gitlab-ci.d/container-cross.yml

@@ -89,7 +89,6 @@ mips64el-debian-cross-container:
 mips-debian-cross-container:
   extends: .container_job_template
   stage: containers
-  needs: ['amd64-debian10-container']
   variables:
     NAME: debian-mips-cross
 

.gitlab-ci.d/crossbuilds.yml

@@ -70,20 +70,6 @@ cross-i386-tci:
     EXTRA_CONFIGURE_OPTS: --target-list=i386-softmmu,i386-linux-user,aarch64-softmmu,aarch64-linux-user,ppc-softmmu,ppc-linux-user
     MAKE_CHECK_ARGS: check check-tcg
 
-cross-mips-system:
-  extends: .cross_system_build_job
-  needs:
-    job: mips-debian-cross-container
-  variables:
-    IMAGE: debian-mips-cross
-
-cross-mips-user:
-  extends: .cross_user_build_job
-  needs:
-    job: mips-debian-cross-container
-  variables:
-    IMAGE: debian-mips-cross
-
 cross-mipsel-system:
   extends: .cross_system_build_job
   needs:

docs/about/build-platforms.rst

@@ -41,7 +41,7 @@ Those hosts are officially supported, with various accelerators:
      - Accelerators
    * - Arm
      - kvm (64 bit only), tcg, xen
-   * - MIPS
+   * - MIPS (little endian only)
      - kvm, tcg
    * - PPC
      - kvm, tcg

docs/about/deprecated.rst

@@ -213,6 +213,19 @@ MIPS ``Trap-and-Emul`` KVM support (since 6.0)
 The MIPS ``Trap-and-Emul`` KVM host and guest support has been removed
 from Linux upstream kernel, declare it deprecated.
 
+Host Architectures
+------------------
+
+BE MIPS (since 7.2)
+'''''''''''''''''''
+
+As Debian 10 ("Buster") moved into LTS the big endian 32 bit version of
+MIPS moved out of support making it hard to maintain our
+cross-compilation CI tests of the architecture. As we no longer have
+CI coverage support may bitrot away before the deprecation process
+completes. The little endian variants of MIPS (both 32 and 64 bit) are
+still a supported host architecture.
+
 QEMU API (QAPI) events
 ----------------------
 

tests/docker/Makefile.include

@@ -81,14 +81,12 @@ endif
 
 # For non-x86 hosts not all cross-compilers have been packaged
 ifneq ($(HOST_ARCH),x86_64)
-DOCKER_PARTIAL_IMAGES += debian-mips-cross debian-mipsel-cross debian-mips64el-cross
+DOCKER_PARTIAL_IMAGES += debian-mipsel-cross debian-mips64el-cross
 DOCKER_PARTIAL_IMAGES += debian-ppc64el-cross
 DOCKER_PARTIAL_IMAGES += debian-s390x-cross
 DOCKER_PARTIAL_IMAGES += fedora
 endif
 
-docker-image-debian-mips-cross: docker-image-debian10
-
 # The native build should never use the registry
 docker-image-debian-native: DOCKER_REGISTRY=
 
@@ -144,6 +142,7 @@ DOCKER_PARTIAL_IMAGES += debian-hppa-cross
 DOCKER_PARTIAL_IMAGES += debian-loongarch-cross
 DOCKER_PARTIAL_IMAGES += debian-m68k-cross debian-mips64-cross
 DOCKER_PARTIAL_IMAGES += debian-microblaze-cross
+DOCKER_PARTIAL_IMAGES += debian-mips-cross
 DOCKER_PARTIAL_IMAGES += debian-nios2-cross
 DOCKER_PARTIAL_IMAGES += debian-riscv64-test-cross
 DOCKER_PARTIAL_IMAGES += debian-sh4-cross debian-sparc64-cross

tests/docker/dockerfiles/debian-mips-cross.docker

@@ -1,32 +1,14 @@
 #
 # Docker mips cross-compiler target
 #
-# This docker target builds on the debian Buster base image.
+# This docker target builds on the Debian Bullseye base image.
 #
-FROM qemu/debian10
+FROM docker.io/library/debian:11-slim
 
-MAINTAINER Philippe Mathieu-Daudé <f4bug@amsat.org>
+RUN export DEBIAN_FRONTEND=noninteractive && \
-
+    apt-get update && \
-# Add the foreign architecture we want and install dependencies
+    apt-get install -y eatmydata && \
-RUN dpkg --add-architecture mips
+    eatmydata apt-get dist-upgrade -y && \
-RUN apt update && \
+    eatmydata apt-get install --no-install-recommends -y \
-    DEBIAN_FRONTEND=noninteractive eatmydata \
+            gcc-mips-linux-gnu \
-    apt install -y --no-install-recommends \
+            libc6-dev-mips-cross
-        gcc-mips-linux-gnu
-
-RUN apt update && \
-    DEBIAN_FRONTEND=noninteractive eatmydata \
-    apt build-dep -yy -a mips --arch-only qemu
-
-# Specify the cross prefix for this image (see tests/docker/common.rc)
-ENV QEMU_CONFIGURE_OPTS --cross-prefix=mips-linux-gnu-
-ENV DEF_TARGET_LIST mips-softmmu,mipsel-linux-user
-
-# Install extra libraries to increase code coverage
-RUN apt update && \
-    DEBIAN_FRONTEND=noninteractive eatmydata \
-    apt install -y --no-install-recommends \
-        libbz2-dev:mips \
-        liblzo2-dev:mips \
-        librdmacm-dev:mips \
-        libsnappy-dev:mips