Re: [PATCH 12/13] KVM: SVM: Add checks for IO instructions

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On 03/31/2011 09:14 AM, Roedel, Joerg wrote:
On Mon, Mar 28, 2011 at 08:28:12AM -0400, Avi Kivity wrote:
>  The spec indicates we need to check the TSS and IOPL based permissions
>  before the intercept (vmx agrees).  With the code as is, it happens
>  afterwards.
>
>  One way to do this is to have an ExtraChecks bit in the opcode::flags.
>  Then opcode::u.xcheck->perms() is the pre-intercept check and
>  opcode::u.xcheck->execute() is the post-intercept execution.  Should
>  work for monitor/mwait/rdtsc(p)/rdpmc/other crap x86 throws at us.

Okay, as you suggested, I put these checks into the instruction emulator
and let the hard work of implementing per-arch checks to the nested-vmx
people ;)
I doubt that this makes the opcode-tables more readable, but lets see :)

I think we're miscommunicating. I'm talking about x86 checks, not virt vendor specific checks.

For example, the flow for IOIO would be:

  #UD check (lock prefix)
  PE/IOPL/CPL/VM check
  TSS bitmap check (can cause #PF)
  Intercept check
  Operand segment check
  Possible #PF
  Execution

We need to make sure the TSS bitmap check happens before the intercept, so we need to split ->execute() into two.

--
error compiling committee.c: too many arguments to function

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