uxen vm-support Linux driver is failing to build with Linux 5.10 kernel

[dozylynx]

I have encountered several compile errors in attempting to build the 4.1.7, 4.1.8 and tip of ascara branch with Linux 5.10 linux-yocto kernel. I am using OpenEmbedded/Yocto tools.

• in v4vvock/v4v_vsock.c: Definitions for sock_no_setsockopt and sock_no_getsockopt are no longer available in the kernel. It looks possible to provide local implementations that just return -EOPNOTSUPP but I haven't determined whether or not this is the right fix.

• in vmdiagnostics/vm_diagnostics.c: real_start_time has been renamed to start_boottime in the task struct.

• in uxenhc/hypercall.c: __vmalloc no longer takes three arguments, and assumes that all callers can accept PAGE_KERNEL - this looks like it might be a challenge for fixing this call site, which currently asks for PAGE_KERNEL_EXEC.

• in uxenhc/hypercall.c: MODULE_LICENSE is failing to expand correctly when it encounters KBUILD_MODFILE within the nested definitions as the macros are resolved. Not sure if this will repro outside the Yocto/OE build environment or not - I can provide repro steps if needed.

We need a way to resolve these in order to support the uxen-guest-tools recipe in the meta-virtualization layer of OpenEmbedded / Yocto.

[HinTak]

FWIW, I was about to post my 6.x compatibility changes (#2), and found that most of the work was already done a few years ago:

https://git.yoctoproject.org/meta-virtualization/tree/recipes-extended/uxen/uxen-guest-tools/0001-vm-support-fix-build-for-kernel-s-5.4.patch?h=master-next

https://git.yoctoproject.org/meta-virtualization/tree/recipes-extended/uxen/uxen-guest-tools/0003-vm-support-fix-build-for-kernel-s-5.14.patch?h=master-next

https://git.yoctoproject.org/meta-virtualization/tree/recipes-extended/uxen/uxen-guest-tools/0002-vm-support-fix-build-for-kernel-s-5.15.patch?h=master-next

That said, since I am building against 6.x, I have gone beyond those (and inclusive of them) already.