Hi Anup,
On 08/09/14 09:17, Anup Patel wrote:
> Instead, of trying out each and every target type we should
> use KVM_ARM_PREFERRED_TARGET vm ioctl to determine target type
> for KVM ARM/ARM64.
>
> If KVM_ARM_PREFERRED_TARGET vm ioctl fails then we fallback to
> old method of trying all known target types.
>
> If KVM_ARM_PREFERRED_TARGET vm ioctl succeeds but the returned
> target type is not known to KVMTOOL then we forcefully init
> VCPU with target type returned by KVM_ARM_PREFERRED_TARGET vm ioctl.
>
> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>
> Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx>
> ---
> tools/kvm/arm/kvm-cpu.c | 52 +++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 41 insertions(+), 11 deletions(-)
>
> diff --git a/tools/kvm/arm/kvm-cpu.c b/tools/kvm/arm/kvm-cpu.c
> index aeaa4cf..ba7a762 100644
> --- a/tools/kvm/arm/kvm-cpu.c
> +++ b/tools/kvm/arm/kvm-cpu.c
> @@ -33,7 +33,8 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> struct kvm_arm_target *target;
> struct kvm_cpu *vcpu;
> int coalesced_offset, mmap_size, err = -1;
> - unsigned int i;
> + unsigned int i, target_type;
> + struct kvm_vcpu_init preferred_init;
> struct kvm_vcpu_init vcpu_init = {
> .features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
> };
> @@ -55,19 +56,47 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> if (vcpu->kvm_run == MAP_FAILED)
> die("unable to mmap vcpu fd");
>
> - /* Find an appropriate target CPU type. */
> - for (i = 0; i < ARRAY_SIZE(kvm_arm_targets); ++i) {
> - if (!kvm_arm_targets[i])
> - continue;
> - target = kvm_arm_targets[i];
> - vcpu_init.target = target->id;
> - err = ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_INIT, &vcpu_init);
> - if (!err)
> - break;
> + /*
> + * If preferred target ioctl successful then use preferred target
> + * else try each and every target type.
> + */
> + err = ioctl(kvm->vm_fd, KVM_ARM_PREFERRED_TARGET, &preferred_init);
> + if (!err) {
> + /* Match preferred target CPU type. */
> + target = NULL;
> + for (i = 0; i < ARRAY_SIZE(kvm_arm_targets); ++i) {
> + if (!kvm_arm_targets[i])
> + continue;
> + if (kvm_arm_targets[i]->id == preferred_init.target) {
> + target = kvm_arm_targets[i];
> + target_type = kvm_arm_targets[i]->id;
> + break;
> + }
> + }
> + if (!target) {
> + target = kvm_arm_targets[0];
I think you missed the part of the patch which adds the now magic zero
member of kvm_arm_targets[]. A simple static initializer should work.
> + target_type = preferred_init.target;
Can't you move that out of the loop, in front of it actually? Then you
can get rid of the line above setting the target_type also, since you
always use the same value now, regardless whether you found that CPU in
the list or not.
> + }
> + } else {
> + /* Find an appropriate target CPU type. */
> + for (i = 0; i < ARRAY_SIZE(kvm_arm_targets); ++i) {
> + if (!kvm_arm_targets[i])
> + continue;
> + target = kvm_arm_targets[i];
> + target_type = target->id;
> + vcpu_init.target = target_type;
> + err = ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_INIT, &vcpu_init);
> + if (!err)
> + break;
> + }
> + if (err)
> + die("Unable to find matching target");
> }
>
> + vcpu_init.target = target_type;
> + err = ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_INIT, &vcpu_init);
You should do this only in the if-branch above, since you (try to) call
KVM_ARM_VCPU_INIT already in the else branch before. Otherwise in the
latter case you would do it twice.
Regards,
Andre.
> if (err || target->init(vcpu))
> - die("Unable to initialise ARM vcpu");
> + die("Unable to initialise vcpu");
>
> coalesced_offset = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION,
> KVM_CAP_COALESCED_MMIO);
> @@ -81,6 +110,7 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
> vcpu->cpu_type = target->id;
> vcpu->cpu_compatible = target->compatible;
> vcpu->is_running = true;
> +
> return vcpu;
> }
>
>
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