> -----Original Message-----
> From: Halil Pasic [mailto:[email protected]]
> Sent: Wednesday, September 27, 2023 12:42 AM
> To: Gonglei (Arei) <[email protected]>
> Cc: Herbert Xu <[email protected]>; [email protected];
> Marc Hartmayer <[email protected]>; Michael S. Tsirkin
> <[email protected]>; Jason Wang <[email protected]>;
> [email protected]; [email protected];
> [email protected]; Halil Pasic <[email protected]>; Cornelia Huck
> <[email protected]>
> Subject: Re: [PATCH] crypto: virtio-crypto: call finalize with bh disabled
>
> [..]
> > --- a/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> > +++ b/drivers/crypto/virtio/virtio_crypto_akcipher_algs.c
> > @@ -61,8 +61,9 @@ static void virtio_crypto_akcipher_finalize_req(
> > vc_akcipher_req->src_buf = NULL;
> > vc_akcipher_req->dst_buf = NULL;
> > virtcrypto_clear_request(&vc_akcipher_req->base);
> > -
> > + local_bh_disable();
> >
> > crypto_finalize_akcipher_request(vc_akcipher_req->base.dataq->engine,
> > req, err);
> > + local_bh_enable();
>
> Thanks Gonglei!
>
> I did this a quick spin, and it does not seem to be sufficient on s390x.
> Which does not come as a surprise to me, because
>
> #define lockdep_assert_in_softirq()
> \
> do
> {
> \
> WARN_ON_ONCE(__lockdep_enabled &&
> \
> (!in_softirq() || in_irq() || in_nmi())); \
> } while (0)
>
> will still warn because in_irq() still evaluates to true (your patch addresses
> the !in_softirq() part).
>
You are right.
So I think the core of this question is: Can we call crypto_finalize_request() in the upper half of the interrupt?
If so, maybe we should introduce a new function, such as lockdep_assert_in_interrupt().
#define lockdep_assert_in_interrupt() \
do { \
WARN_ON_ONCE(__lockdep_enabled && !in_interrupt()); \
} while (0)
If not, why?
Herbert, do you have any suggestions? Thanks.
Regards,
-Gonglei
> I don't have any results on x86 yet. My current understanding is that the
> virtio-pci transport code disables interrupts locally somewhere in the call chain
> (actually in vp_vring_interrupt() via spin_lock_irqsave()) and then x86 would be
> fine. But I will get that verified.
>
> On the other hand virtio_airq_handler() calls vring_interrupt() with interrupts
> enabled. (While vring_interrupt() is called in a (read) critical section in
> virtio_airq_handler() we use read_lock() and not read_lock_irqsave() to grab
> the lock. Whether that is correct in it self (i.e. disregarding the crypto problem)
> or not I'm not sure right now. Will think some more about it tomorrow.) If the
> way to go forward is disabling interrupts in virtio-ccw before vring_interrupt() is
> called, I would be glad to spin a patch for that.
>
> Copying Conny, as she may have an opinion on this (if I'm not wrong she
> authored that code).
>
> Regards,
> Halil