On Jul 06 23:10, Philippe Mathieu-Daudé wrote: > +Peter/Paolo > > On 7/6/21 10:47 PM, Aaron Lindsay wrote: > > Hello, > > > > I previously supplied a patch which modified the plugin interface such > > that it will return physical addresses for IO regions [0]. However, I > > have now found a case where the interface does not appear to correctly > > return the full physical addresses. > > > > In particular, when in qemu_plugin_hwaddr_phys_addr() for a particular > > store to IO memory (haddr->is_io==true), I find that haddr->v.io.offset > > is 0x0 and mrs->mr->addr is 0x3000, meaning 0x3000 is the returned > > "physical address". However, I also find that > > mrs->offset_within_address_space is 0x8000007000 (and also that > > 0x8000007000 matches up with what an actual translation would be from > > inspecting the page tables). > > > > Would it be 'safe' to *always* begin using > > mrs->offset_within_address_space as the returned physical address here > > instead of `haddr->v.io.offset + mrs->mr->addr`, or is there a reason we > > should not do that?
I realized this was perhaps not clear, so for clarification, I am imagining the formula for calculating the address would be: `mrs->offset_within_address_space + mrs->mr->addr`. Perhaps this was a confusing example since the offset into the region is 0x0... > 'safety' is not my area, but using mrs->offset_within_address_space > sounds correct to me. I'm not sure I was as clear as I could be here, either. My primary concern was/is correctness of the address calculation, so perhaps 'safe' was not the right way to put this. -Aaron
