Re: [Xen-devel] [PATCH 14/15] x86/hvm: Prepare to allow use of system segments for memory references

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.11.16 at 16:38, <andrew.cooper3@xxxxxxxxxx> wrote:
> All system segments (GDT/IDT/LDT and TR) describe a linear address and limit,
> and act similarly to user segments.  However all current uses of these tables
> in the emulator opencode the address calculations and limit checks.  In
> particular, no care is taken for access which wrap around the 4GB or
> non-canonical boundaries.
> 
> Alter hvm_virtual_to_linear_addr() to cope with performing segmentation checks
> on system segments.  This involves restricting access checks in the 32bit case
> to user segments only, and adding presence/limit checks in the 64bit case.
> 
> When suffering a segmentation fault for a system segments, return
> X86EMUL_EXCEPTION but leave the fault injection to the caller.  The fault type
> depends on the higher level action being performed.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Jan Beulich <JBeulich@xxxxxxxx>

I think the code that this covered has been moved elsewhere,
so please use
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
here instead.

Jan


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