Thanks to the people who offered to review and test (and Jurgen for
having already done so).
To patch the existing driver during boot, try the following:
- Boot with the debugger loaded, and break in early (-kd).
- When the debugger loads, set a breakpoint to fire when the xnf
driver is attached:
[0]> ::bp xnf`xnf_attach
[0]> :c
- When the breakpoint fires, we need to patch xnf_getcapab():
[0]> xnf_getcapab::dis
xnf`xnf_getcapab: pushq %rbp
xnf`xnf_getcapab+1: movq %rsp,%rbp
xnf`xnf_getcapab+4: subq $0x20,%rsp
xnf`xnf_getcapab+8: movq %rdi,-0x8(%rbp)
xnf`xnf_getcapab+0xc: movq %rsi,-0x10(%rbp)
xnf`xnf_getcapab+0x10: movq %rdx,-0x18(%rbp)
xnf`xnf_getcapab+0x14: cmpl $0x1,%esi
xnf`xnf_getcapab+0x17: jne +0x14 <xnf`xnf_getcapab+0x2d>
xnf`xnf_getcapab+0x19: cmpl $0x0,0x48(%rdi)
xnf`xnf_getcapab+0x1d: jne +0x6 <xnf`xnf_getcapab+0x25>
xnf`xnf_getcapab+0x1f: xorl %eax,%eax
xnf`xnf_getcapab+0x21: movl %eax,(%rdx)
xnf`xnf_getcapab+0x23: jmp +0xd <xnf`xnf_getcapab+0x32>
xnf`xnf_getcapab+0x25: movl $0x4,(%rdx)
^ this needs to be a 2
xnf`xnf_getcapab+0x2b: jmp +0x5 <xnf`xnf_getcapab+0x32>
xnf`xnf_getcapab+0x2d: cmpl $0x2,%esi
xnf`xnf_getcapab+0x30: jne +0x7 <xnf`xnf_getcapab+0x39>
xnf`xnf_getcapab+0x32: movl $0x1,%eax
xnf`xnf_getcapab+0x37: jmp +0x2 <xnf`xnf_getcapab+0x3b>
xnf`xnf_getcapab+0x39: xorl %eax,%eax
xnf`xnf_getcapab+0x3b: leave
xnf`xnf_getcapab+0x3c: ret
- do the patching:
[0]> xnf_getcapab+0x25/3 B
xnf`xnf_getcapab+0x25: c7 2 4
[0]> xnf_getcapab+0x27/B
xnf`xnf_getcapab+0x27: 4
[0]> xnf_getcapab+0x27/v 2
xnf`xnf_getcapab+0x27: 0x4 = 0x2
- check that it worked:
[0]> xnf_getcapab+0x25::dis -n 1
xnf`xnf_getcapab+0x23: jmp +0xd <xnf`xnf_getcapab+0x32>
xnf`xnf_getcapab+0x25: movl $0x2,(%rdx)
xnf`xnf_getcapab+0x2b: jmp +0x5 <xnf`xnf_getcapab+0x32>
[0]> :c
- Everything should come up normally, with the exception that
checksum offload should work properly.
Don't forget to get rid of the /etc/system tunable for
xnf_checksum_offload before you do this!
dme.
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