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

Alexandru Elisei alexandru.elisei at arm.com
Thu May 8 01:12:53 AEST 2025


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 at 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



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