Re: [Xen-devel] [PATCH v2] docs: add PVH specification

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 18.09.14 at 17:27, <roger.pau@xxxxxxxxxx> wrote:
> +All the segments selectors are set with a flat base at zero.
> +
> +The `cs` segment selector attributes are set to 0x0a09b, which describes an
> +executable and readable code segment only accessible by the most privileged
> +level. The segment is also set as a 64-bit code segment (`L` flag set) with a
> +default operation size of 16bits (`D` flag unset).

There's no such thing - the L bit set requires the D bit to be clear
_without_ this meaning a default operation size of 16 bits.

> +The remaining segment selectors (`ds`, `ss`, `es`, `fs` and `gs`) are all set
> +to the same values. The attributes are set to 0x0c093, which implies a read 
> and
> +write data segment only accessible by the most privileged level. It is 
> important
> +to notice that for the `ss` selector the stack is set to use a 32bit pointer
> +(`B` flag set).

The B bit really has no meaning in 64-bit mode, and the stack pointer
will always be a 64-bit one.

> +The `RFLAGS` register is guaranteed to be clear when jumping into the kernel
> +entry point.

Kind of: The reserved bit 1 will always be set.

Jan


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