Re: [Xen-devel] [PATCH] x86/PV: properly populate descriptor tables

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Sep 23, 2015 at 09:34:16AM -0600, Jan Beulich wrote:
> Us extending the GDT limit past the Xen descriptors so far meant that
> guests (including user mode programs) accessing any descriptor table
> slot above the original OS'es limit but below the first Xen descriptor
> caused a #PF, converted to a #GP in our #PF handler. Which is quite
> different from the native behavior, where some of such accesses (LAR
> and LSL) don't fault. Mimic that behavior by mapping a blank page into
> unused slots.
> 
> While not strictly required, treat the LDT the same for consistency.
> 
> Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> Not sure about 4.6 here: Beyond Andrew noticing I don't think anyone
> ran into this issue in a real world environment, and hence it doesn't
> seem to be too critical to get this fixed.
> 

Given that this is not absolutely essential (fix critical bug or
regressions) I would like it to go in after 4.6.

Wei.

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