Re: [PATCH 01/11] memattrs: add debug attribute

Dr. David Alan Gilbert
2020-12-01T11:05:34Z

* Ashish Kalra (Ashish.Kalra@amd.com) wrote:
> From: Brijesh Singh <brijesh.singh@amd.com>
>
> From: Brijesh Singh <brijesh.singh@amd.com>
>
> Extend the MemTxAttrs to include a 'debug' flag. The flag can be used as
> general indicator that operation was triggered by the debugger.
>
> A subsequent patch will set the debug=1 when issuing a memory access
> from the gdbstub or HMP commands. This is a prerequisite to support
> debugging an encrypted guest. When a request with debug=1 is seen, the
> encryption APIs will be used to access the guest memory.

Is this also the flag that would be used for memory dumping?

> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
> include/exec/memattrs.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
> index 95f2d20d55..c8b56389d6 100644
> --- a/include/exec/memattrs.h
> +++ b/include/exec/memattrs.h
> @@ -49,6 +49,8 @@ typedef struct MemTxAttrs {
> unsigned int target_tlb_bit0 : 1;
> unsigned int target_tlb_bit1 : 1;
> unsigned int target_tlb_bit2 : 1;
> + /* Memory access request from the debugger */
> + unsigned int debug:1;

It might be good to clarify that this is for QEMU debug features, not
guest side debug features (e.g. CPU debug facilities/registers)

Dave

> } MemTxAttrs;
>
> /* Bus masters which don't specify any attributes will get this,
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK