[PATCH 1/5] kvmtool: ARM: Use KVM_ARM_PREFERRED_TARGET vm ioctl to determine target cpu

[Anup Patel <anup.patel@linaro.org>]

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.

We bail-out target type returned by KVM_ARM_PREFERRED_TARGET vm ioctl
is not known to kvmtool.

Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Signed-off-by: Anup Patel <anup.patel@linaro.org>
---
 tools/kvm/arm/kvm-cpu.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/tools/kvm/arm/kvm-cpu.c b/tools/kvm/arm/kvm-cpu.c
index aeaa4cf..7478f8f 100644
--- a/tools/kvm/arm/kvm-cpu.c
+++ b/tools/kvm/arm/kvm-cpu.c
@@ -34,6 +34,7 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
 	struct kvm_cpu *vcpu;
 	int coalesced_offset, mmap_size, err = -1;
 	unsigned int i;
+	struct kvm_vcpu_init preferred_init;
 	struct kvm_vcpu_init vcpu_init = {
 		.features = ARM_VCPU_FEATURE_FLAGS(kvm, cpu_id)
 	};
@@ -46,6 +47,10 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
 	if (vcpu->vcpu_fd < 0)
 		die_perror("KVM_CREATE_VCPU ioctl");
 
+	err = ioctl(kvm->vm_fd, KVM_ARM_PREFERRED_TARGET, &preferred_init);
+	if (err < 0)
+		die_perror("KVM_ARM_PREFERRED_TARGET ioctl");
+
 	mmap_size = ioctl(kvm->sys_fd, KVM_GET_VCPU_MMAP_SIZE, 0);
 	if (mmap_size < 0)
 		die_perror("KVM_GET_VCPU_MMAP_SIZE ioctl");
@@ -55,17 +60,22 @@ 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. */
+	/* Match preferred target CPU type. */
+	target = NULL;
 	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)
+		if (kvm_arm_targets[i]->id == preferred_init.target) {
+			target = kvm_arm_targets[i];
 			break;
+		}
+	}
+	if (!target) {
+		die("preferred target not available\n");
 	}
 
+	vcpu_init.target = preferred_init.target;
+	err = ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_INIT, &vcpu_init);
 	if (err || target->init(vcpu))
 		die("Unable to initialise ARM vcpu");
 
@@ -81,6 +91,7 @@ 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;
 }
 
-- 
1.7.9.5