On Thu, 11 Sep 2025, Peter Maydell wrote:
On Thu, 11 Sept 2025 at 15:49, Sebastian Ott <sebott@xxxxxxxxxx> wrote:
This series adds a vcpu knob to request a specific PSCI version
from KVM via the KVM_REG_ARM_PSCI_VERSION FW register.
Note: in order to support PSCI v0.1 we need to drop vcpu
initialization with KVM_CAP_ARM_PSCI_0_2 in that case.
Alternatively we could limit support to versions >=0.2 .
Sebastian Ott (2):
target/arm/kvm: add constants for new PSCI versions
target/arm/kvm: add kvm-psci-version vcpu property
Could we have some rationale, please? What's the use case
where you might need to specify a particular PSCI version?
The use case is migrating between different host kernel versions.
Per default the kernel reports the latest PSCI version in the
KVM_REG_ARM_PSCI_VERSION register (for KVM_CAP_ARM_PSCI_0_2) -
when that differs between source and target a migration will fail.
This property allows to request a PSCI version that is supported by
both sides. Specifically I want to support migration between host
kernels with and without the following Linux commit:
8be82d536a9f KVM: arm64: Add support for PSCI v1.2 and v1.3
Regards,
Sebastian
