RE: [PATCH v2 4/4] crypto: starfive - Add hash and HMAC support

[JiaJie Ho]

> -----Original Message-----
> From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Sent: 9 February, 2023 5:44 PM
> To: JiaJie Ho <jiajie.ho@xxxxxxxxxxxxxxxx>
> Cc: David S . Miller <davem@xxxxxxxxxxxxx>; Rob Herring
> <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@xxxxxxxxxx>; Emil Renner Berthing
> <kernel@xxxxxxxx>; Conor Dooley <conor.dooley@xxxxxxxxxxxxx>; linux-
> crypto@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-riscv@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 4/4] crypto: starfive - Add hash and HMAC support
> 
> On Thu, Feb 09, 2023 at 09:33:06AM +0000, JiaJie Ho wrote:
> >
> > The DMA can only support 32-bit addressing.
> > So, I am copying everything in case kernel allocated memory region >32-bit
> for a user app.
> 
> Does your hardware support scatter-and-gather? If so you should at least
> allocate individual pages rather than one contiguous buffer.
> 
> Then you can allocate them on-demand rather than before-hand.
> 
> It would also be nice to not do the copy if the input you were given was in
> low memory (and contiguous if your hardware doesn't do SG).
> 

I'll try this then.

Thanks,
Jia Jie