On 09/14/2015 10:23 AM, Paolo Bonzini wrote: > > > On 14/09/2015 19:21, Richard Henderson wrote: >>>> About implementing DE in TCG: I really don't think it is easier, but if >>>>>> somebody wants to implement it, it would be welcome. >>>> >>>> Actually I agree that it's easier, and even a partial implementation >>>> (e.g. no I/O port breakpoints) would be nice to have because recent >>>> Windows IIRC requires DE. >> Isn't I/O port breakpoints the only thing we're missing from DE? > > I was thinking of the CR4 bit, but it looks like we don't raise #GP at > all on writes to unknown CR0 or CR4 bits.
Nor do we #gp accesses to dr[45] with DE, nor map dr[45] to dr[67] without DE. Does the i/o breakpoint happen before or after the access? If before, we could implement the breakpoint in check_io. Otherwise we'd need a new helper. r~
