[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] x86/vmx: Don't clobber exception_bitmap when entering/leaving emulated real mode
>>> On 27.01.16 at 19:11, <andrew.cooper3@xxxxxxxxxx> wrote: > Most updates to the exception bitmaps set or clear an individual bits. > > However, entering or exiting emulated real mode unilaterally clobbers it, > leaving the exit code to recalculate what it should have been. This is > error > prone, and indeed currently fails to recalculate the TRAP_no_device > intercept > appropriately. > > Instead of overwriting exception_bitmap when entering emulated real mode, > move > the override into vmx_update_exception_bitmap() and leave exception_bitmap > unmodified. > > This means that recalculation is unnecessary, and that the use of > vmx_fpu_leave() and vmx_update_debug_state() while in emulated real mode > doesn't result in TRAP_no_device and TRAP_int3 being un-intercepted. > > This is only a functional change on hardware lacking unrestricted guest > support. > > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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