Re: [Xen-devel] [PATCH] x86: refine debugging of SMEP/SMAP fix

2016-05-17 Thread Jan Beulich
>>> On 17.05.16 at 14:56, wrote: > On 17/05/16 11:42, Jan Beulich wrote: > On 17.05.16 at 12:28, 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

Re: [Xen-devel] [PATCH] x86: refine debugging of SMEP/SMAP fix

2016-05-17 Thread Andrew Cooper
On 17/05/16 11:42, Jan Beulich wrote: On 17.05.16 at 12:28, 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 de

Re: [Xen-devel] [PATCH] x86: refine debugging of SMEP/SMAP fix

2016-05-17 Thread Jan Beulich
>>> On 17.05.16 at 12:28, 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 d

Re: [Xen-devel] [PATCH] x86: refine debugging of SMEP/SMAP fix

2016-05-17 Thread Andrew Cooper
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

[Xen-devel] [PATCH] x86: refine debugging of SMEP/SMAP fix

2016-05-17 Thread Jan Beulich
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. Also there is one more place for XEN_CR4_PV32_BITS to be used. Signed-off-by: J