* [PATCH v2 2/2] target/arm/kvm: add kvm-psci-version vcpu property
2025-10-30 16:59 [PATCH v2 0/2] arm: add kvm-psci-version vcpu property Sebastian Ott
2025-10-30 16:59 ` [PATCH v2 1/2] target/arm/kvm: add constants for new PSCI versions Sebastian Ott
@ 2025-10-30 16:59 ` Sebastian Ott
1 sibling, 0 replies; 3+ messages in thread
From: Sebastian Ott @ 2025-10-30 16:59 UTC (permalink / raw)
To: Peter Maydell, Paolo Bonzini, Eric Auger
Cc: qemu-arm, qemu-devel, kvm, kvmarm, Sebastian Ott
Provide a kvm specific vcpu property to override the default
(as of kernel v6.13 that would be PSCI v1.3) PSCI version emulated
by kvm. Current valid values are: 0.1, 0.2, 1.0, 1.1, 1.2, and 1.3
Signed-off-by: Sebastian Ott <sebott@redhat.com>
---
docs/system/arm/cpu-features.rst | 5 +++
target/arm/cpu.h | 6 ++++
target/arm/kvm.c | 60 +++++++++++++++++++++++++++++++-
3 files changed, 70 insertions(+), 1 deletion(-)
diff --git a/docs/system/arm/cpu-features.rst b/docs/system/arm/cpu-features.rst
index 37d5dfd15b..1d32ce0fee 100644
--- a/docs/system/arm/cpu-features.rst
+++ b/docs/system/arm/cpu-features.rst
@@ -204,6 +204,11 @@ the list of KVM VCPU features and their descriptions.
the guest scheduler behavior and/or be exposed to the guest
userspace.
+``kvm-psci-version``
+ Override the default (as of kernel v6.13 that would be PSCI v1.3)
+ PSCI version emulated by the kernel. Current valid values are:
+ 0.1, 0.2, 1.0, 1.1, 1.2, and 1.3
+
TCG VCPU Features
=================
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 39f2b2e54d..c2032070b7 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -981,6 +981,12 @@ struct ArchCPU {
*/
uint32_t psci_version;
+ /*
+ * Intermediate value used during property parsing.
+ * Once finalized, the value should be read from psci_version.
+ */
+ uint32_t prop_psci_version;
+
/* Current power state, access guarded by BQL */
ARMPSCIState power_state;
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 0d57081e69..c53b307b76 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -484,6 +484,49 @@ static void kvm_steal_time_set(Object *obj, bool value, Error **errp)
ARM_CPU(obj)->kvm_steal_time = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
}
+struct psci_version {
+ uint32_t number;
+ const char *str;
+};
+
+static const struct psci_version psci_versions[] = {
+ { QEMU_PSCI_VERSION_0_1, "0.1" },
+ { QEMU_PSCI_VERSION_0_2, "0.2" },
+ { QEMU_PSCI_VERSION_1_0, "1.0" },
+ { QEMU_PSCI_VERSION_1_1, "1.1" },
+ { QEMU_PSCI_VERSION_1_2, "1.2" },
+ { QEMU_PSCI_VERSION_1_3, "1.3" },
+ { -1, NULL },
+};
+
+static char *kvm_get_psci_version(Object *obj, Error **errp)
+{
+ ARMCPU *cpu = ARM_CPU(obj);
+ const struct psci_version *ver;
+
+ for (ver = psci_versions; ver->number != -1; ver++) {
+ if (ver->number == cpu->prop_psci_version)
+ return g_strdup(ver->str);
+ }
+
+ g_assert_not_reached();
+}
+
+static void kvm_set_psci_version(Object *obj, const char *value, Error **errp)
+{
+ ARMCPU *cpu = ARM_CPU(obj);
+ const struct psci_version *ver;
+
+ for (ver = psci_versions; ver->number != -1; ver++) {
+ if (!strcmp(value, ver->str)) {
+ cpu->prop_psci_version = ver->number;
+ return;
+ }
+ }
+
+ error_setg(errp, "Invalid PSCI-version value");
+}
+
/* KVM VCPU properties should be prefixed with "kvm-". */
void kvm_arm_add_vcpu_properties(ARMCPU *cpu)
{
@@ -505,6 +548,12 @@ void kvm_arm_add_vcpu_properties(ARMCPU *cpu)
kvm_steal_time_set);
object_property_set_description(obj, "kvm-steal-time",
"Set off to disable KVM steal time.");
+
+ object_property_add_str(obj, "kvm-psci-version", kvm_get_psci_version,
+ kvm_set_psci_version);
+ object_property_set_description(obj, "kvm-psci-version",
+ "Set PSCI version. "
+ "Valid values are 0.1, 0.2, 1.0, 1.1, 1.2, 1.3");
}
bool kvm_arm_pmu_supported(void)
@@ -1959,7 +2008,8 @@ int kvm_arch_init_vcpu(CPUState *cs)
if (cs->start_powered_off) {
cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_POWER_OFF;
}
- if (kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PSCI_0_2)) {
+ if (cpu->prop_psci_version != QEMU_PSCI_VERSION_0_1 &&
+ kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PSCI_0_2)) {
cpu->psci_version = QEMU_PSCI_VERSION_0_2;
cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_PSCI_0_2;
}
@@ -1998,6 +2048,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
}
+ if (cpu->prop_psci_version) {
+ psciver = cpu->prop_psci_version;
+ ret = kvm_set_one_reg(cs, KVM_REG_ARM_PSCI_VERSION, &psciver);
+ if (ret) {
+ error_report("PSCI version %"PRIx64" is not supported by KVM", psciver);
+ return ret;
+ }
+ }
/*
* KVM reports the exact PSCI version it is implementing via a
* special sysreg. If it is present, use its contents to determine
--
2.42.0
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