On Thu, Jun 06, 2019 at 12:17:39AM +0300, Eugene Korenevsky wrote: > Intel SDM vol. 3, 5.3: > The processor causes a > general-protection exception (or, if the segment is SS, a stack-fault > exception) any time an attempt is made to access the following addresses > in a segment: > - A byte at an offset greater than the effective limit > - A word at an offset greater than the (effective-limit – 1) > - A doubleword at an offset greater than the (effective-limit – 3) > - A quadword at an offset greater than the (effective-limit – 7) > > Therefore, the generic limit checking error condition must be > > exn = (off > limit + 1 - access_len) = (off + access_len - 1 > limit) > > but not > > exn = (off + access_len > limit) > > as for now. > > Also avoid integer overflow of `off` at 32-bit KVM by casting it to u64. > > Note: access length is currently sizeof(u64) which is incorrect. This > will be fixed in the subsequent patch. > > Signed-off-by: Eugene Korenevsky <ekorenevsky@xxxxxxxxx> > --- Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
