On Wed Nov 19, 2025 at 3:30 PM JST, John Hubbard wrote:
> On 11/18/25 5:54 PM, Alexandre Courbot wrote:
>> On Sat Nov 15, 2025 at 8:30 AM JST, Timur Tabi wrote:
>>> The GSP booter firmware in Turing and GA100 includes a third memory
>>> section called ImemNs, which is non-secure IMEM. This section must
>>> be loaded separately from DMEM and secure IMEM, but only if it
>>> actually exists.
>>>
>>> Signed-off-by: Timur Tabi <[email protected]>
>>> ---
>>> drivers/gpu/nova-core/falcon.rs | 18 ++++++++++++++++--
>>> drivers/gpu/nova-core/firmware/booter.rs | 9 +++++++++
>>> drivers/gpu/nova-core/firmware/fwsec.rs | 5 +++++
>>> 3 files changed, 30 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/nova-core/falcon.rs
>>> b/drivers/gpu/nova-core/falcon.rs
>>> index 0e0935dbb927..ece8b92a627e 100644
>>> --- a/drivers/gpu/nova-core/falcon.rs
>>> +++ b/drivers/gpu/nova-core/falcon.rs
>>> @@ -239,6 +239,8 @@ fn from(value: PeregrineCoreSelect) -> Self {
>>> pub(crate) enum FalconMem {
>>> /// Secure Instruction Memory.
>>> ImemSec,
>>> + /// Non-Secure Instruction Memory.
>>> + ImemNs,
>>
>> So, seeing how this is taking shape I now think we should just have one
>> Imem variant:
>>
>> Imem { secure: bool },
>
> ohhh, boolean args are usually not a good idea, because they make the
> callsite non-self-documenting.
>
> That's also true even in magical languages such as Rust. :)
I fully agree; that's why I made the field named so its name needs to be
specified every time. :) Maybe `is_secure` would have been better
though.
>
> Let's prefer enum args over bools, generally, please. So for example
> (there are other ways to structure things, and this is just the
> enum aspect of it):
>
> enum ImemSecurity {
> Secure,
> NonSecure,
> }
>
> Imem { security: ImemSecurity },
That would change
FalconMem::Imem { secure: true }
into
FalconMem::Imem {security: ImemSecurity::Secure }
If we want to use an enum I think we can remove the name:
Imem(ImemSecurity),
So we can specify `Imem` as
FalconMem::Imem(ImemSecurity::Secure)
which is as explicit, and a bit shorter.
>
>>
>> This makes matching easier for the common case of "we want to do
>> something in case of Imem, regardless of the secure flag". Something
>> like
>>
>> FalconMem::ImemSec | FalconMem::ImemNs => {
>>
>> becomes:
>>
>> FalconMem::Imem { .. } => {
>>
>> And if you need to use the flag, you can change e.g.:
>>
>> FalconMem::ImemSec | FalconMem::ImemNs => {
>> regs::NV_PFALCON_FALCON_IMEMC::default()
>> .set_secure(target_mem == FalconMem::ImemSec)
>>
>> into
>>
>> FalconMem::Imem { secure } => {
>
> See, this is hard and misleading to read. It reads like "secure
> Imem", until you think at it a bit. Devastating! :)
Renaming into `is_secure` would alleviate that, but the `ImemSecurity`
enum is arguably as good, so I'm fine with it as well.
And an enum can also be used as a type to method arguments, which
carries more semantics than `is_secure: bool`. So agreed, this is
better.
