Re: [PATCH v2 02/17] psp: base PSP device support

Willem de Bruijn
2025-06-26T14:25:13Z

Jakub Kicinski wrote:
> On Wed, 25 Jun 2025 19:55:01 -0400 Willem de Bruijn wrote:
> > > +#define PSP_SPI_KEY_ID GENMASK(30, 0)
> > > +#define PSP_SPI_KEY_PHASE BIT(31)
> > > +
> > > +#define PSPHDR_CRYPT_OFFSET GENMASK(5, 0)
> > > +
> > > +#define PSPHDR_VERFL_SAMPLE BIT(7)
> > > +#define PSPHDR_VERFL_DROP BIT(6)
> > > +#define PSPHDR_VERFL_VERSION GENMASK(5, 2)
> > > +#define PSPHDR_VERFL_VIRT BIT(1)
> > > +#define PSPHDR_VERFL_ONE BIT(0)
> >
> > Use bitfields in struct psphdr rather than manual bit twiddling?
>
> Some call it manual bit twiddling, some call it the recommended kernel
> coding style? ;)

:)

Preferable over the following?

struct psphdr {
u8 nexthdr;
u8 hdrlen;
u8 crypt_offset;

u8 sample:1;
u8 drop:1;
u8 version:4;
u8 vc_present:1;
u8 reserved:1;

__be32 spi;
__be64 iv;
__be64 vc[]; /* optional */
};

I suppose that has an endianness issue requiring
variants with __LITTLE_ENDIAN_BITFIELD and
__BIG_ENDIAN_BITFIELD.

Either way, just a thought.

> > Or else just consider just calling it flags rather than verfl
> > (which stands for version and flags?).
>
> (Yes.)
>
> > > +
> > > +/**
> > > + * struct psp_dev_config - PSP device configuration
> > > + * @versions: PSP versions enabled on the device
> > > + */
> > > +struct psp_dev_config {
> > > + u32 versions;
> > > +};
> > > +
> > > +/**
> > > + * struct psp_dev - PSP device struct
> > > + * @main_netdev: original netdevice of this PSP device
> >
> > This makes sense with a single physical device plus optional virtual
> > (vlan, bonding, ..) devices.
> >
> > It may also be possible for a single physical device (with single
> > device key) to present multiple PFs and/or VFs. In that case, will
> > there be multiple struct psp_dev, or will one PF be the "main".
>
> AFAIU we have no ability to represent multi-PCIe function devices
> in the kernel model today. So realistically I think psp_dev per
> function and then propagate the rotation events.

IDPF does support multiple "vports" (num_alloc_vports), and with that
struct net_device, from a single BDF.