On Mon, Aug 12, 2013 at 08:35:57PM +0800, Arthur Chunqi Li wrote: > Hi Gleb and Paolo, > There are some corner cases when testing I/O bitmaps, and I don't know > the exact action of HW. > A little bit late but... > 1. If we set bit of 0x4000 in bitmap and call inl(0x3FFFF) or > inl(0x4000) in guest, what will get of exit information? > Spec says; execution of an I/O instruction causes a VM exit if any bit in the I/O bitmaps corresponding to a port it accesses is 1. Note "any" here. The exit will have address that instruction used, otherwise how can we be able to emulate it properly. > 2. What will we get when calling inl(0xFFFF) in guest with/without > “unconditional I/O exiting” VM-execution control and “use I/O bitmaps” > VM-execution control? In other words are you asking what happens if you do inl(0xFFFF) on real HW? "The result of an attempt to address beyond the I/O address space limit of FFFFH is implementation-specific" > > I test the two cases in nested env. For the first one, I got normal > exit if any of the port accessed is masked in bitmap. For the second, > it will acts the same as other ports. And the SDM says "If an I/O > operation “wraps around” the 16-bit I/O-port space (accesses ports > FFFFH and 0000H), the I/O instruction causes a VM exit." I cannot find > the exact reaction of this case. What do you mean by "exact reaction"? > > Do you have any ideas about these? > > Arthur > > -- > Arthur Chunqi Li > Department of Computer Science > School of EECS > Peking University > Beijing, China -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
