Re: [Xen-devel] [PATCH RFC V5 4/5] xen, libxc: Request page fault injection via libxc

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 08/06/2014 06:58 PM, Razvan Cojocaru wrote:
> Added new XEN_DOMCTL_set_pagefault_info hypercall, used by libxc's
> new xc_domain_set_pagefault_info() function to set per-domain page
> fault injection information. All a call does is set per-domain info,
> and nothing actually happens until VMENTRY time, and then only if
> all conditions are met (the guest is in user mode, the set value
> matches CR3, and there are no other pending traps).
> This mechanism allows bringing in swapped-out pages for inspection.
> 
> Changes since V2:
>  - Removed superfluous memset(&ctxt, 0, sizeof(struct hvm_hw_cpu)).
>  - Now checking SS.DPL instead of CS.DPL to see if the guest is in
>    user mode.
>  - Removed superfluous fault_info members initialization.
>  - Now returning -EINVAL if !has_hvm_container_domain(d) on
>    XEN_DOMCTL_set_pagefault_info.
>  - Moved struct fault_info from struct domain to struct hvm_domain.
>  - Collapsed explicit initialization of the fault_info members into a
>    one-line assignment on the tools/libxc side.
>  - Now using write_access as a proper bool instead of shifting and
>    OR-ing it with PFEC_user_mode.
> 
> Changes since V3:
>  - Now checking that is_hvm_domain(d) in do_domctl() (consistent with
>    the test in the actual page fault injection code).
>  - XEN_DOMCTL_set_pagefault_info now extends the proper range.
>  - Added a likely() around the
>    d->arch.hvm_domain.fault_info.virtual_address == 0 check.
>  - Replaced hvm_funcs.save_cpu_ctxt() function call with lighter code.
>  - Split the vmx.c page fault injection function into a check
>    function and an inject function.
> 
> Changes since V4:
>  - Added "valid" flag instead of relying on virtual address 0 as a
>    special case.
>  - Using #defines instead of magic constants in vmx_vmcs_save().
>  - Padded struct xen_domctl_set_pagefault_info.
>  - Coding style and readability changes.
> 
> Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>

Sorry, forgot the

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

on this one.


Thanks,
Razvan Cojocaru

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