Re: [PATCH v2 02/22] include/xen/slr-table.h: Secure Launch Resource Table definitions

[Jan Beulich <jbeulich@xxxxxxxx>]

On 24.05.2025 00:19, Sergii Dmytruk wrote:
> On Wed, May 21, 2025 at 05:45:04PM +0200, Jan Beulich wrote:
>>> +/*
>>> + *  Copyright (c) 2025 Apertus Solutions, LLC
>>> + *  Copyright (c) 2025 Oracle and/or its affiliates.
>>> + *  Copyright (c) 2025 3mdeb Sp. z o.o
>>
>> I'm curious: Considering the (just) 2 S-o-b, where's the 3rd copyright
>> line coming from?
> 
> I'll add "Daniel P. Smith" (already in CC), not sure why his S-o-B
> wasn't there.

Just to mention it: Be careful there; aiui you can't simply add someone else's
S-o-b without their agreement.

>>> +#define UEFI_SLR_TABLE_GUID \
>>> +    { 0x877a9b2aU, 0x0385, 0x45d1, { 0xa0, 0x34, 0x9d, 0xac, 0x9c, 0x9e, 
>>> 0x56, 0x5f } }
>>
>> I'm not sure this is a good place to put UEFI GUIDs. Considering e.g ...
> 
> It's here because the GUID is related more to SLRT than to EFI.  I can
> move it if there is a more fitting place for table GUIDs.

It'll (at least somewhat) depend on where it's going to be used. A common 
problem
when definitions / declarations are introduced without any use.

>>> +/*
>>> + * Primary SLR Table Header
>>> + */
>>> +struct slr_table
>>> +{
>>> +    uint32_t magic;
>>> +    uint16_t revision;
>>> +    uint16_t architecture;
>>> +    uint32_t size;
>>> +    uint32_t max_size;
>>> +    /* entries[] */
>>> +} __packed;
>>
>> If x86-specific, the question on the need for some of the __packed arises
>> again.
> 
> The table is used to communicate data from pre-DRTM world to DRTM-world
> and is produced and consumed by unrelated software components that don't
> necessarily pad structures the same way by default.

How do other environments matter when this header is solely used by Xen?

>>> +/*
>>> + * Prototype of a function pointed to by slr_entry_dl_info::dl_handler.
>>> + */
>>> +typedef void (*dl_handler_func)(struct slr_bl_context *bl_context);
>>
>> It being an internal header, ...
>>> +    uint64_t dl_handler;
>>
>> ... why can't this type be used here then? This would presumably avoid a
>> typecast later.
> 
> It's not an internal header in my understanding of the phrase, Xen
> parses what a bootloader has passed to it.  In principle, pointers could
> be 32-bit here.

"Internal" as opposed to "public", i.e. what's exposed to guests.

Jan