It will be very useful for user space (QEMU/KVMTOOL) if it has a method of querying VCPU target type matching to underlying Host. We can use such querying mechanism and implement machine models in user space where VCPU target type is always same-as/similar-to underlying Host (i.e. Target CPU=Host).
This patch series implements KVM_ARM_PREFERRED_TARGET vm ioclt for querying VCPU target type matching underlying host. Using this new ioctl we can implement VCPU target CPU=Host in user space.
Also, it is not mandatory to call KVM_ARM_PREFERRED_TARGET vm ioctl and the old method of trying all possible target types using the KVM_ARM_VCPU_INIT ioctl to initialize VCPU works fine.
V5: - Update documentation based on review comments
V4: - Fixed files exchanged between patches - For now return zeroed features in struct kvm_vcpu_init instance
V3: - Return -ENODEV if no preferred target available for host - Make KVM_ARM_PREFERRED_TARGET ioctl as vm ioctl
V2: - Renamed the ioclt to KVM_ARM_PREFERRED_TARGET - Return struct kvm_vcpu_init instace instead of just target type
V1: - Initial patch-set with ioctl named as KVM_ARM_SUITABLE_TARGET
Anup Patel (4): ARM: KVM: Implement kvm_vcpu_preferred_target() function ARM64: KVM: Implement kvm_vcpu_preferred_target() function ARM/ARM64: KVM: Implement KVM_ARM_PREFERRED_TARGET ioctl KVM: Add documentation for KVM_ARM_PREFERRED_TARGET ioctl
Documentation/virtual/kvm/api.txt | 31 +++++++++++++++++++++++++++---- arch/arm/include/asm/kvm_host.h | 1 + arch/arm/kvm/arm.c | 13 +++++++++++++ arch/arm/kvm/guest.c | 20 ++++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/guest.c | 20 ++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 7 files changed, 83 insertions(+), 4 deletions(-)