Hi all,
I’m trying to make Vchan work on camkes-arm-vm in the process I encountered a couple problems. Hope you can give me some advice. I knew that Vchan is out dated and never finished on ARM. But it seems the only option for now (please correct me if I’m wrong).
Here is what I did so far:
1. modified tk1_vmlinux.c by adding the virtual device and fault handler and installed it to guest linux with vm_add_device(vm, &vchan_dev);
--------------------------------------------------- vchan_device_fault_handler(struct device* d UNUSED, vm_t* vm, fault_t* fault){ //uint32_t data = fault_get_data(fault); uint32_t data = fault_get_ctx(fault)->r1; vchan_entry_point(vm, data); // fflush(stdout); advance_fault(fault); return 0; }
struct device vchan_dev = { .devid = DEV_CUSTOM, .name = "vchan-driver", .pstart = 0x2040000, .size = 0x1000, .handle_page_fault = &vchan_device_fault_handler, .priv = NULL, }; ---------------------------------------------------
2. compiled linux-tegra using buildroot (by the way the current linux-tegra is 4.9.0 which is not supported by buildroot-2016, the earliest version works for me is buildroot-2017-2), added a vmm-manager kernel driver similar to the one in camkes-x86-vm. But I changed the call_into_hypervisor() to the following:
--------------------------------------------------- int call_into_hypervisor(int cmd, void *data, size_t sz, vmcall_args_t *vmcall) {
int res = 0; int err; unsigned phys_ptr = virt_to_phys(vmcall);
vmcall->data = data; vmcall->cmd = cmd; vmcall->phys_data = virt_to_phys(data); vmcall->size = sz;
down(&hyp_sem);
/* Set up arguments for the ARM hyp call */ asm volatile ("mov r0, %0; mov r1, %1" : : "r" (VMM_MANAGER_TOKEN), "r" (phys_ptr): "%r0", "%r1"); asm volatile (".arch_extension virt\n\t” "hvc #0"); asm volatile ("mov %0, r0" : "=r" (res) : : );
err = vargs->err; up(&hyp_sem); return err; } ---------------------------------------------------
The kernel built and run correctly. But when I try to install the kernel driver. It crashed with following information.
--------------------------------------------------- # modprobe driver.ko [81.826621] driver: loading out-of-tree module taints kernel Bad sys call from [Linux]: scone 0 at PC: 0xbf000214 Assertion failed” !err (/camkes-arm-vm/libs/libsel4arm-vmm/src/vm.c: vm_event: 407) —————————————————————————
I’m not sure if this error is triggered by the modified call_into_hypervisor() or by event_thread_run()->eventfd_signal().
Any help would be appreciated! Thanks in advance.
Best Regards -Daniel Wang