Re: [Qemu-devel] 3 new x86 instructions

[Torbjorn Granlund]

Richard Henderson <address@hidden> writes:

  Yes, and "-cpu Haswell" will enable the BMI extensions.
  
I have used git://repo.or.cz/qemu/rth.git x86-next checked out around 15
January for a while now.  The host system is Debian GNU/Linux amd64 and
the guest is FreeBSD 9.1 amd64.

I now updated x86-next in order to get support for adox/adcx.

The current sources causes a problem inside FreeBSD's sshd.  Debugging a
bit reveals that it gets a SIGFPE at a 'div' instruction inside
/lib/libcrypto.so.6's BN_div function.  The instruction is correct in
raising SIGFPE (or whatever the instruction-level counterpart is
called), since the dividend / divisor is too large to fit a 64-bit
quotient (or said differently: the high word in rdx is >= than the
divisor [in r13]).

I have not tracked down why execution leads to these invalid operands.
I cannot therefore state with any certainty that this is a bug in the
qemu variant used.

-- 
Torbjörn