Gleb Natapov wrote: > On Wed, Feb 17, 2010 at 01:11:36PM +0200, Avi Kivity wrote: >> On 02/15/2010 03:30 PM, Gleb Natapov wrote: >>>> I just did this on our primary AMD platform (Embedded Opteron, 13KS EE), >>>> and it just worked. >>>> >>>> But this is a fairly new processor. Consequently, it reports NextRIP >>>> support via cpuid function 0x8000000A. Looking for an older one too. >>>> >>>> In the meantime I also browsed a bit more in the manuals, and I don't >>>> think stepping over or (what is actually required) into an INT3 will >>>> work. We can't step into as the processor clears TF on any event handler >>>> entry. And stepping over would cause troubles >>>> >>>> a) as an unknown amount of code may run without #DB interception >>>> b) we would fiddle with TF in code that is already under debugger >>>> control, thus we would very likely run into conflicts. >>>> >>>> Leaves us with tricky INT3 emulation. Sigh. >>>> >>> So the question is do we want to support this kind of debugging on older >>> AMDs. May we don't. >> How much older are they? >> > Actually I am not sure new AMDs support this correctly. Need one to run > tests. GDB is not a good test case, it is too smart. It works well - and gdb is far from being "smart": one byte off the expected INT3 address, and everything falls apart. That's what the VMX bug demonstrated. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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
