ARM coverage test case test_create_device failure on some machines with gnu toolchain

[MrXinWang]

Referencing discussion in PR #87, ARM coverage test case test_create_device will fail on some machines with gnu toolchain. This failure is caused by the assertion in arm test_create_device case:
assert_eq(errno::Error::last().errno(), 25);
as ioctl device_fd.set_device_attr(&dist_attr) returns EINVAL instead of ENOTTY.

Note that this bug is only reproducible in only some of the arm64 machines, and using musl toolchain also will not lead to this problem. Root cause of this bug needs to be investigated and fixed.

[aw]

Hello,

I believe VGIC_V3 requires an online vCPU prior to setting device attributes, see here.

Add this before set_device_attr assert in src/ioctls/device.rs#L290:

vm.create_vcpu(0).unwrap();

Tested successfully on an arm64 device, with musl and libc. Hope this helps.

/cc @andreeaflorescu

[andreeaflorescu]

Thanks for looking into this @aw! Do you want to contribute the required change as well? Or should we open a PR with it?

[aw]

Sure I can make a PR.