[kvm-unit-tests PATCH v3 13/16] scripts: Do not probe for maximum number of VCPUs when using kvmtool

Alexandru Elisei
2025-05-07T15:13:59Z

The --probe-maxsmp parameter updates MAX_SMP with the maximum number of
VCPUs that the host supports. Qemu will exit with an error when creating a
virtual machine if the number of VCPUs is exceeded.

kvmtool behaves differently: it will automatically limit the number of
VCPUs to the what KVM supports, which is exactly what --probe-maxsmp wants
to achieve. When doing --probe-maxsmp with kvmtool, print a message
explaining why it's redundant and don't do anything else.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
run_tests.sh | 3 ++-
scripts/runtime.bash | 16 ----------------
scripts/vmm.bash | 24 ++++++++++++++++++++++++
3 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/run_tests.sh b/run_tests.sh
index 150a06a91064..a69c3665b7a4 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -10,6 +10,7 @@ if [ ! -f config.mak ]; then
fi
source config.mak
source scripts/common.bash
+source scripts/vmm.bash

function usage()
{
@@ -90,7 +91,7 @@ while [ $# -gt 0 ]; do
list_tests="yes"
;;
--probe-maxsmp)
- probe_maxsmp
+ ${vmm_opts[$TARGET:probe_maxsmp]}
;;
--)
;;
diff --git a/scripts/runtime.bash b/scripts/runtime.bash
index 01ec8eae2bba..a802686c511d 100644
--- a/scripts/runtime.bash
+++ b/scripts/runtime.bash
@@ -209,19 +209,3 @@ function run()

return $ret
}
-
-#
-# Probe for MAX_SMP, in case it's less than the number of host cpus.
-#
-function probe_maxsmp()
-{
- local smp
-
- if smp=$($RUNTIME_arch_run _NO_FILE_4Uhere_ -smp $MAX_SMP |& grep 'SMP CPUs'); then
- smp=${smp##* }
- smp=${smp/\(}
- smp=${smp/\)}
- echo "Restricting MAX_SMP from ($MAX_SMP) to the max supported ($smp)" >&2
- MAX_SMP=$smp
- fi
-}
diff --git a/scripts/vmm.bash b/scripts/vmm.bash
index a1d50ed51981..ef9819f4132c 100644
--- a/scripts/vmm.bash
+++ b/scripts/vmm.bash
@@ -105,6 +105,22 @@ function qemu_parse_premature_failure()
return 0
}

+#
+# Probe for MAX_SMP, in case it's less than the number of host cpus.
+#
+function qemu_probe_maxsmp()
+{
+ local smp
+
+ if smp=$($RUNTIME_arch_run _NO_FILE_4Uhere_ -smp $MAX_SMP |& grep 'SMP CPUs'); then
+ smp=${smp##* }
+ smp=${smp/\(}
+ smp=${smp/\)}
+ echo "Restricting MAX_SMP from ($MAX_SMP) to the max supported ($smp)" >&2
+ MAX_SMP=$smp
+ fi
+}
+
function kvmtool_parse_premature_failure()
{
local log="$@"
@@ -114,6 +130,12 @@ function kvmtool_parse_premature_failure()
return 0
}

+function kvmtool_probe_maxsmp()
+{
+ echo "kvmtool automatically limits the number of VCPUs to maximum supported"
+ echo "The 'smp' test parameter won't be modified"
+}
+
declare -A vmm_opts=(
[qemu:nr_cpus]='-smp'
[qemu:kernel]='-kernel'
@@ -122,6 +144,7 @@ declare -A vmm_opts=(
[qemu:default_opts]=''
[qemu:fixup_return_code]=qemu_fixup_return_code
[qemu:parse_premature_failure]=qemu_parse_premature_failure
+ [qemu:probe_maxsmp]=qemu_probe_maxsmp

[kvmtool:nr_cpus]='--cpus'
[kvmtool:kernel]='--kernel'
@@ -130,6 +153,7 @@ declare -A vmm_opts=(
[kvmtool:default_opts]="$KVMTOOL_DEFAULT_OPTS"
[kvmtool:fixup_return_code]=kvmtool_fixup_return_code
[kvmtool:parse_premature_failure]=kvmtool_parse_premature_failure
+ [kvmtool:probe_maxsmp]=kvmtool_probe_maxsmp
)

function check_vmm_supported()
--
2.49.0