On 20/11/25 11:10, Eric Auger wrote:


On 11/13/25 1:05 PM, Sebastian Ott wrote:
Hi Philippe,

On Wed, 12 Nov 2025, Philippe Mathieu-Daudé wrote:
On 12/11/25 19:13, Sebastian Ott wrote:
  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

  Note: in order to support PSCI v0.1 we need to drop vcpu
  initialization with KVM_CAP_ARM_PSCI_0_2 in that case.

  Signed-off-by: Sebastian Ott <[email protected]>
  ---
    docs/system/arm/cpu-features.rst |  5 +++
    target/arm/cpu.h                 |  6 +++
    target/arm/kvm.c                 | 64
+++++++++++++++++++++++++++++++-
    3 files changed, 74 insertions(+), 1 deletion(-)


  diff --git a/target/arm/kvm.c b/target/arm/kvm.c
  index 0d57081e69..e91b1abfb8 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 },
  +};


  @@ -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");

Could we enumerate from psci_versions[] here?


Hm, we'd need to concatenate these. Either manually:
"Valid values are " psci_versions[0].str ", " psci_versions[1].str ",
" ... which is not pretty and still needs to be touched for a new
version.

Or by a helper function that puts these in a new array and uses smth like
g_strjoinv(", ", array);
But that's quite a bit of extra code that needs to be maintained without
much gain.

Or we shy away from the issue and rephrase that to:
"Valid values include 1.0, 1.1, 1.2, 1.3"
Personally I would vote for keeping it as is

OK.

(by the way why did you
moit 0.1 and 0.2 above?)

Eric

Since the intended use case is via machine types and I don't expect a
lot of users setting the psci version manually - I vote for option 3.

Opinions?

Sebastian



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