On 17/05/16 11:42, Jan Beulich wrote: >>>> On 17.05.16 at 12:28, <andrew.coop...@citrix.com> wrote: >> On 17/05/16 10:54, Jan Beulich wrote: >>> Instead of just latching cr4_pv32_mask into %rdx, correct the found >>> wrong value in %cr4 (to avoid triggering another BUG). The value left >>> in %rdx should be sufficient for deducing cr4_pv32_mask from the >>> register dump. >> Alternatively, you can reuse %rax (as its value is useless by this >> point) and leave %rdx as exactly cr4_pv32_mask. This avoids needing a >> subsequent step to reverse engineer cr4_pv32_mask. > I don't view the value in %rax as useless - that's the set of bits > we have found set, which didn't match our expectation. Hence I > specifically don't want to re-use that register.
Ok. We don't need to preserve any registers from the caller, so using a different one such as %rbx or %rcx would be fine. The issue is that it is important to see precisely what cr4_pv32_mask is. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
