Road map

[Martins3]

review mode

• how kvm_main works

ideas

• host should work in another thread, then anything did in host_loop just like another thread, so it works just like two threads run in parallel.

[Martins3]

TODO

• kvm_kick_many_cpus : how it works internally, it seems without any hardware support
• some function is static, kvm_trap_vz_handle_tlb_st_miss e.g., but I changed in dune, may lead to compiling problem

[Martins3]

Until I have no ideas, no todo and no question, can I compile the code.

[Martins3]

• 查看一下 access_ok 在 mips 上和 x86 上的不同。

[Martins3]

• use CMakelist
• make these ioctl works
• init
  • create CPU

[Martins3]

• /home/maritns3/core/tool/mips/kvm-cpu.c: kvm_cpu__set_debug_fd, so we can debug guset with debug_fd ?

[Martins3]

• Loongson sdm : gpsi 11.3.1

[Martins3]

• host has to map PROT_EXEC ?

// TODO why kvmtool ignored PROT_EXEC ?
#define PROT_RWX (PROT_READ | PROT_WRITE |PROT_EXEC)
#define MAP_ANON_NORESERVE (MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE)

static inline void *alloc_ebase()
{
	void * addr = mmap(NULL, 1 << PAGESIZE, PROT_RWX, MAP_ANON_NORESERVE, -1, 0);
  if(addr == NULL)
    die_perror("alloc_ebase");

  return addr;
}

[Martins3]

• TLB refill need page walk, in See MIPS Run, it's done by software, but with PW* registers, TLB refill can be done with hardware.

[Martins3]

• see 6.2.3 “Exception Vector Locations” on page 103)

[Martins3]

We can do better

• why I can't run continue the program in the guest syscall handler
• guest and host share as minimal resources as possible
  • eg, guest can close any file descriptor?
• I hope I can run the unmodified binary
• We should share the same address space, so host and guest live in two threads
• can I let it run in python / rust / go ?

[Martins3]

• it's weird to ignore cause register on vcpu_put and vcpu_load
• check vcpu_load, what if two vm use same physical in turn ?