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Re: [Xen-devel] [PATCH RFC V5 2/5] xen: Optimize introspection access to guest state

>>> On 06.08.14 at 17:58, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
> Speed optimization for introspection purposes: a handful of registers
> are sent along with each mem_event. This requires enlargement of the
> mem_event_request / mem_event_response stuctures, and additional code
> to fill in relevant values. Since the EPT event processing code needs
> more data than CR3 or MSR event processors, hvm_mem_event_fill_regs()
> fills in less data than p2m_mem_event_fill_regs(), in order to avoid
> overhead. Struct hvm_hw_cpu has been considered instead of the custom
> struct mem_event_regs_st, but its size would cause quick filling up
> of the mem_event ring buffer.
> Changes since V1:
>  - Replaced guest_x86_mode with cs_arbytes in the mem_event_regs_st
>    structure.
>  - Removed superfluous preprocessor check for __x86_64__ in
>    p2m_mem_event_fill_regs().
> Changes since V2:
>  - Removed inline function compiler suggestions.
>  - Removed superfluous memset(&ctxt, 0, sizeof(struct hvm_hw_cpu)).
>  - Padded struct mem_event_regs_st.
>  - Renamed mem_event_regs_t to mem_event_regs.
>  - Readability changes.
> Changes since V3:
>  - Changed the name of VCPU variables referring to the current
>    VCPU to "curr".
>  - Renamed "mem_event_regs" to "x86_mem_event_regs" to make it
>    explicit.
> Changes since V4:
>  - Renamed "x86_mem_event_regs" to "mem_event_regs_x86" and
>    removed a typedef.

Looks pretty okay to me now; the one desire left would be for you to
make all the new code you add const-correct.


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