Keir Fraser
2005-Jun-08 21:28 UTC
Re: [Xen-devel] [patch] nx bit shouldn''t get set when disabled
On 8 Jun 2005, at 22:30, Ian Pratt wrote:>>> Definitions such as __PAGE_KERNEL set NX, but as Jun pointed out, >>> those should only be set when NX mode is enabled. >> >> So the extra masking isn''t required? > > I suspect normal hardware is prepared to put up with the bit being set > even if its not supported...I doubt that, actually. But the kernel ought to set NX in __PAGE_KERNEL only when the hardware supports it (__PAGE_KERNEL is a variable these days, not a macro). -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ian Pratt
2005-Jun-08 21:30 UTC
RE: [Xen-devel] [patch] nx bit shouldn''t get set when disabled
> >> Why the extra mask ops with __supported_pte_mask? Native x86/64 > >> builds obviously don''t need them... > > > > Definitions such as __PAGE_KERNEL set NX, but as Jun pointed out, > > those should only be set when NX mode is enabled. > > So the extra masking isn''t required?I suspect normal hardware is prepared to put up with the bit being set even if its not supported... Ian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel