From c869f4129c8e35f3c234d757c0227c53134aca16 Mon Sep 17 00:00:00 2001 From: Andrea Bolognani Date: Mon, 27 Jan 2025 19:29:22 +0100 Subject: binfmt: Shuffle things around This should make no difference from the functional point of view and it's just preparation for upcoming changes. Signed-off-by: Andrea Bolognani Reviewed-by: Alistair Francis Reviewed-by: Laurent Vivier Message-ID: <20250127182924.103510-2-abologna@redhat.com> Signed-off-by: Alistair Francis --- scripts/qemu-binfmt-conf.sh | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'scripts') diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh index 6ef9f11..426f075 100755 --- a/scripts/qemu-binfmt-conf.sh +++ b/scripts/qemu-binfmt-conf.sh @@ -318,20 +318,23 @@ qemu_set_binfmts() { mask=$(eval echo \$${cpu}_mask) family=$(eval echo \$${cpu}_family) + target="$cpu" + if [ "$cpu" = "i486" ] ; then + target="i386" + fi + + qemu="$QEMU_PATH/qemu-$target$QEMU_SUFFIX" + if [ "$magic" = "" ] || [ "$mask" = "" ] || [ "$family" = "" ] ; then echo "INTERNAL ERROR: unknown cpu $cpu" 1>&2 continue fi - qemu="$QEMU_PATH/qemu-$cpu" - if [ "$cpu" = "i486" ] ; then - qemu="$QEMU_PATH/qemu-i386" + if [ "$host_family" = "$family" ] ; then + continue fi - qemu="$qemu$QEMU_SUFFIX" - if [ "$host_family" != "$family" ] ; then - $BINFMT_SET - fi + $BINFMT_SET done } -- cgit v1.1 From 2770a46b20b7ccd23019a7b6b6631de933b53c8e Mon Sep 17 00:00:00 2001 From: Andrea Bolognani Date: Mon, 27 Jan 2025 19:29:23 +0100 Subject: binfmt: Normalize host CPU architecture Right now information regarding the family each CPU type belongs to is recorded in two places: the large data table at the top of the script, and the qemu_host_family() function. We can make things better by mapping host CPU architecture to QEMU target in the few cases where the two don't already match and then using the data table to look up the family, same as we're already doing for the guest CPU architecture. Being able to reason in terms of QEMU target regardless of whether we're looking at the host or guest CPU architecture will come in handy to implement upcoming changes. A couple of entries are dropped in the process: BePC and Power Macintosh. I'm quite certain neither of those have ever been reported as CPU architectures by Linux. I believe many more of the entries that are carried forward could be dropped as well, but I don't have the same level of confidence there so I decided to play it safe just in case. Signed-off-by: Andrea Bolognani Reviewed-by: Alistair Francis Reviewed-by: Laurent Vivier Message-ID: <20250127182924.103510-3-abologna@redhat.com> Signed-off-by: Alistair Francis --- scripts/qemu-binfmt-conf.sh | 44 +++++++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 19 deletions(-) (limited to 'scripts') diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh index 426f075..8d9136a 100755 --- a/scripts/qemu-binfmt-conf.sh +++ b/scripts/qemu-binfmt-conf.sh @@ -144,35 +144,35 @@ loongarch64_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x loongarch64_mask='\xff\xff\xff\xff\xff\xff\xff\xfc\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff' loongarch64_family=loongarch -qemu_get_family() { - cpu=${HOST_ARCH:-$(uname -m)} +# Converts the name of a host CPU architecture to the corresponding QEMU +# target. +# +# FIXME: This can probably be simplified a lot by dropping most entries. +# Remember that the script is only used on Linux, so we only need to +# handle the strings Linux uses to report the host CPU architecture. +qemu_normalize() { + cpu="$1" case "$cpu" in - amd64|i386|i486|i586|i686|i86pc|BePC|x86_64) + i[3-6]86) echo "i386" ;; - mips*) - echo "mips" + amd64) + echo "x86_64" ;; - "Power Macintosh"|ppc64|powerpc|ppc) + powerpc) echo "ppc" ;; - ppc64el|ppc64le) - echo "ppcle" + ppc64el) + echo "ppc64le" ;; - arm|armel|armhf|arm64|armv[4-9]*l|aarch64) + armel|armhf|armv[4-9]*l) echo "arm" ;; - armeb|armv[4-9]*b|aarch64_be) + armv[4-9]*b) echo "armeb" ;; - sparc*) - echo "sparc" - ;; - riscv*) - echo "riscv" - ;; - loongarch*) - echo "loongarch" + arm64) + echo "aarch64" ;; *) echo "$cpu" @@ -309,7 +309,13 @@ EOF qemu_set_binfmts() { # probe cpu type - host_family=$(qemu_get_family) + host_cpu=$(qemu_normalize ${HOST_ARCH:-$(uname -m)}) + host_family=$(eval echo \$${host_cpu}_family) + + if [ "$host_family" = "" ] ; then + echo "INTERNAL ERROR: unknown host cpu $host_cpu" 1>&2 + exit 1 + fi # register the interpreter for each cpu except for the native one -- cgit v1.1 From 1887cf2368189087fdf977fb8d09b5ad47cc7aea Mon Sep 17 00:00:00 2001 From: Andrea Bolognani Date: Mon, 27 Jan 2025 19:29:24 +0100 Subject: binfmt: Add --ignore-family option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Until now, the script has worked under the assumption that a host CPU can run binaries targeting any CPU in the same family. That's a fair enough assumption when it comes to running i386 binaries on x86_64, but it doesn't quite apply in the general case. For example, while riscv64 CPUs could theoretically run riscv32 applications natively, in practice there exist few (if any?) CPUs that implement the necessary silicon; moreover, even if you had one such CPU, your host OS would most likely not have enabled the necessary kernel bits. This new option gives distro packagers the ability to opt out of the assumption, likely on a per-architecture basis, and make things work out of the box for a larger fraction of their user base. As an interesting side effect, this makes it possible to enable execution of 64-bit binaries on 32-bit CPUs of the same family, which is a perfectly valid use case that apparently hadn't been considered until now. Link: https://src.fedoraproject.org/rpms/qemu/pull-request/72 Thanks: David Abdurachmanov Thanks: Daniel P. Berrangé Signed-off-by: Andrea Bolognani Reviewed-by: Alistair Francis Reviewed-by: Laurent Vivier Message-ID: <20250127182924.103510-4-abologna@redhat.com> Signed-off-by: Alistair Francis --- scripts/qemu-binfmt-conf.sh | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'scripts') diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh index 8d9136a..5fd462b 100755 --- a/scripts/qemu-binfmt-conf.sh +++ b/scripts/qemu-binfmt-conf.sh @@ -205,6 +205,9 @@ Usage: qemu-binfmt-conf.sh [--qemu-path PATH][--debian][--systemd CPU] --persistent: if yes, the interpreter is loaded when binfmt is configured and remains in memory. All future uses are cloned from the open file. + --ignore-family: if yes, it is assumed that the host CPU (e.g. riscv64) + can't natively run programs targeting a CPU that is + part of the same family (e.g. riscv32). --preserve-argv0 preserve argv[0] To import templates with update-binfmts, use : @@ -337,7 +340,12 @@ qemu_set_binfmts() { fi if [ "$host_family" = "$family" ] ; then - continue + # When --ignore-family is used, we have to generate rules even + # for targets that are in the same family as the host CPU. The + # only exception is of course when the CPU types exactly match + if [ "$target" = "$host_cpu" ] || [ "$IGNORE_FAMILY" = "no" ] ; then + continue + fi fi $BINFMT_SET @@ -355,10 +363,11 @@ CREDENTIAL=no PERSISTENT=no PRESERVE_ARG0=no QEMU_SUFFIX="" +IGNORE_FAMILY=no _longopts="debian,systemd:,qemu-path:,qemu-suffix:,exportdir:,help,credential:,\ -persistent:,preserve-argv0:" -options=$(getopt -o ds:Q:S:e:hc:p:g:F: -l ${_longopts} -- "$@") +persistent:,preserve-argv0:,ignore-family:" +options=$(getopt -o ds:Q:S:e:hc:p:g:F:i: -l ${_longopts} -- "$@") eval set -- "$options" while true ; do @@ -418,6 +427,10 @@ while true ; do shift PRESERVE_ARG0="$1" ;; + -i|--ignore-family) + shift + IGNORE_FAMILY="$1" + ;; *) break ;; -- cgit v1.1