diff mbox series

efi_loader: Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again in efi_net_receive()

Message ID 163158520452.224107.7330406153367961192.stgit@localhost
State Superseded
Delegated to: Heinrich Schuchardt
Headers show
Series efi_loader: Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again in efi_net_receive() | expand

Commit Message

Masami Hiramatsu Sept. 14, 2021, 2:06 a.m. UTC 
From: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>

Since 'this->int_status' is cleared by efi_net_get_status(), if user
does wait_for_event(wait_for_packet) and efi_net_get_status() loop
and there are several received packets on the buffer, the second
efi_net_get_status() does not return EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
even if the 'wait_for_packet' is ready.

This happens on "efiboot selftest" with noisy network.
(The network device can receive both of other packets and dhcp discover
 packet in a short time.)

Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again when we found any
packet still on the receive buffer.

Signed-off-by: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
---
 lib/efi_loader/efi_net.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

Comments

Heinrich Schuchardt Sept. 14, 2021, 3:45 p.m. UTC | #1 
On 9/14/21 4:06 AM, Masami Hiramatsu wrote:
> From: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
>
> Since 'this->int_status' is cleared by efi_net_get_status(), if user

Is it correct to clear int_status unconditionally in efi_net_get_status()?

Shouldn't two consecutive calls to EFI_SIMPLE_NETWORK.GetStatus() return
the same result?

Best regards

Heinrich

> does wait_for_event(wait_for_packet) and efi_net_get_status() loop
> and there are several received packets on the buffer, the second
> efi_net_get_status() does not return EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> even if the 'wait_for_packet' is ready.
>
> This happens on "efiboot selftest" with noisy network.
> (The network device can receive both of other packets and dhcp discover
>   packet in a short time.)
>
> Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again when we found any
> packet still on the receive buffer.
>
> Signed-off-by: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
> ---
>   lib/efi_loader/efi_net.c |   13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> index 69276b275d..9ca1e0c354 100644
> --- a/lib/efi_loader/efi_net.c
> +++ b/lib/efi_loader/efi_net.c
> @@ -640,10 +640,19 @@ static efi_status_t EFIAPI efi_net_receive
>   	*buffer_size = receive_lengths[rx_packet_idx];
>   	rx_packet_idx = (rx_packet_idx + 1) % ETH_PACKETS_BATCH_RECV;
>   	rx_packet_num--;
> -	if (rx_packet_num)
> +	if (rx_packet_num) {
> +		/*
> +		 * Since 'this->int_status' is cleared by efi_net_get_status(),
> +		 * if user does wait_for_event(wait_for_packet) and
> +		 * efi_net_get_status() again, EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> +		 * is not set even if 'wait_for_packet' is ready.
> +		 * Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again here.
> +		 */
> +		this->int_status |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
>   		wait_for_packet->is_signaled = true;
> -	else
> +	} else {
>   		this->int_status &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> +	}
>   out:
>   	return EFI_EXIT(ret);
>   }
>
Masami Hiramatsu Sept. 15, 2021, 1:31 a.m. UTC | #2 
Hi Heinrich,

This is obscure in the specification (I can not see any detailed
description about EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT).
If EFI_SIMPLE_NETWORK.GetStatus() returns only the hardware interrupt
state, it is an useless interface, because it doesn't sync to the
status of the packet buffer and wait_for_event() result.
If EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT is set only if the rx
interrupts (this is not the rx interrupt in U-Boot anyway...) is
coming, the efi selftest code must not use the net->get_status() for
checking the packet is received, or call net->receive() until the
packet buffer is empty(EFI_NOT_READY) (and also, it has to ensure the
packet buffer is empty before calling wait_for_event()).

So, I think the correct test code will be something like this;

submit_dhcp_discover()
for (;;) {
  wait_for_event(net)
  net->get_status() // and check receive interrupt
  while (net->receive() != EFI_NOT_READY) {
     // check dhcp reply
  }
}

Thank you,

2021年9月15日(水) 0:45 Heinrich Schuchardt <xypron.glpk@gmx.de>:

>
> On 9/14/21 4:06 AM, Masami Hiramatsu wrote:
> > From: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
> >
> > Since 'this->int_status' is cleared by efi_net_get_status(), if user
>
> Is it correct to clear int_status unconditionally in efi_net_get_status()?
>
> Shouldn't two consecutive calls to EFI_SIMPLE_NETWORK.GetStatus() return
> the same result?
>
> Best regards
>
> Heinrich
>
> > does wait_for_event(wait_for_packet) and efi_net_get_status() loop
> > and there are several received packets on the buffer, the second
> > efi_net_get_status() does not return EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> > even if the 'wait_for_packet' is ready.
> >
> > This happens on "efiboot selftest" with noisy network.
> > (The network device can receive both of other packets and dhcp discover
> >   packet in a short time.)
> >
> > Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again when we found any
> > packet still on the receive buffer.
> >
> > Signed-off-by: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
> > Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
> > ---
> >   lib/efi_loader/efi_net.c |   13 +++++++++++--
> >   1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> > index 69276b275d..9ca1e0c354 100644
> > --- a/lib/efi_loader/efi_net.c
> > +++ b/lib/efi_loader/efi_net.c
> > @@ -640,10 +640,19 @@ static efi_status_t EFIAPI efi_net_receive
> >       *buffer_size = receive_lengths[rx_packet_idx];
> >       rx_packet_idx = (rx_packet_idx + 1) % ETH_PACKETS_BATCH_RECV;
> >       rx_packet_num--;
> > -     if (rx_packet_num)
> > +     if (rx_packet_num) {
> > +             /*
> > +              * Since 'this->int_status' is cleared by efi_net_get_status(),
> > +              * if user does wait_for_event(wait_for_packet) and
> > +              * efi_net_get_status() again, EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> > +              * is not set even if 'wait_for_packet' is ready.
> > +              * Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again here.
> > +              */
> > +             this->int_status |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> >               wait_for_packet->is_signaled = true;
> > -     else
> > +     } else {
> >               this->int_status &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> > +     }
> >   out:
> >       return EFI_EXIT(ret);
> >   }
> >
>


--
Masami Hiramatsu
Masami Hiramatsu Sept. 15, 2021, 10:15 a.m. UTC | #3 
Hi Heinrich,

2021年9月15日(水) 10:31 Masami Hiramatsu <masami.hiramatsu@linaro.org>:
>
> Hi Heinrich,
>
> This is obscure in the specification (I can not see any detailed
> description about EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT).

OK, I checked the UEFI specification v2.9 again.
The main purpose of EFI_SIMPLE_NETWORK.GetStatus() seems to update the
EFI_SIMPLE_NETWORK_MODE::MediaPresent, in other words, it checks link
status.
And InterruptStatus of EFI_SIMPLE_NETWORK.GetStatus() means "the
currently active interrupts", not "packet to be received".
Thus, I think it should be tested for checking the link status instead
of checking receive packets in DHCP.
You also can see the EFI_SIMPLE_NETWORK_PROTOCOL::WaitForPacket
ensures that you can receive the packet (The spec says "Event used
with EFI_BOOT_SERVICES.WaitForEvent() to wait for a packet to be
received." )
So, it is enough to use the WaitForPacket in the packet receiving
loop, no need to use GetStatus(). Then, correct test should be
something like this.

----
net->get_status();
if (!net->mode.MediaPresent) {
   error(no link up!)
   return;
}

submit_dhcp_discover()
for (;;) {
   wait_for_event(net)
   while (net->receive() != EFI_NOT_READY) {
      // check dhcp reply
   }
}
----

For your information, as far as I can see, the interrupt bit is
cleared or not depends on the platform driver implementation in EDK2
too.
In many cases (e.g. virtio-net), they do not clear the original bits,
in another case, no interrupt bit supported (IntrruptStatus always be
0).
But I couldn't find the code which really cleared the interrupt bit...
So I think there is a difference between UEFI specification and
reference implementation (EDK2).

Thank you,


>
> Thank you,
>
> 2021年9月15日(水) 0:45 Heinrich Schuchardt <xypron.glpk@gmx.de>:
>
> >
> > On 9/14/21 4:06 AM, Masami Hiramatsu wrote:
> > > From: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
> > >
> > > Since 'this->int_status' is cleared by efi_net_get_status(), if user
> >
> > Is it correct to clear int_status unconditionally in efi_net_get_status()?
> >
> > Shouldn't two consecutive calls to EFI_SIMPLE_NETWORK.GetStatus() return
> > the same result?
> >
> > Best regards
> >
> > Heinrich
> >
> > > does wait_for_event(wait_for_packet) and efi_net_get_status() loop
> > > and there are several received packets on the buffer, the second
> > > efi_net_get_status() does not return EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> > > even if the 'wait_for_packet' is ready.
> > >
> > > This happens on "efiboot selftest" with noisy network.
> > > (The network device can receive both of other packets and dhcp discover
> > >   packet in a short time.)
> > >
> > > Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again when we found any
> > > packet still on the receive buffer.
> > >
> > > Signed-off-by: Kazuhiko Sakamoto <sakamoto.kazuhiko@socionext.com>
> > > Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
> > > ---
> > >   lib/efi_loader/efi_net.c |   13 +++++++++++--
> > >   1 file changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> > > index 69276b275d..9ca1e0c354 100644
> > > --- a/lib/efi_loader/efi_net.c
> > > +++ b/lib/efi_loader/efi_net.c
> > > @@ -640,10 +640,19 @@ static efi_status_t EFIAPI efi_net_receive
> > >       *buffer_size = receive_lengths[rx_packet_idx];
> > >       rx_packet_idx = (rx_packet_idx + 1) % ETH_PACKETS_BATCH_RECV;
> > >       rx_packet_num--;
> > > -     if (rx_packet_num)
> > > +     if (rx_packet_num) {
> > > +             /*
> > > +              * Since 'this->int_status' is cleared by efi_net_get_status(),
> > > +              * if user does wait_for_event(wait_for_packet) and
> > > +              * efi_net_get_status() again, EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
> > > +              * is not set even if 'wait_for_packet' is ready.
> > > +              * Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again here.
> > > +              */
> > > +             this->int_status |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> > >               wait_for_packet->is_signaled = true;
> > > -     else
> > > +     } else {
> > >               this->int_status &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
> > > +     }
> > >   out:
> > >       return EFI_EXIT(ret);
> > >   }
> > >
> >
>
>
> --
> Masami Hiramatsu



--
Masami Hiramatsu
diff mbox series

Patch

diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
index 69276b275d..9ca1e0c354 100644
--- a/lib/efi_loader/efi_net.c
+++ b/lib/efi_loader/efi_net.c
@@ -640,10 +640,19 @@  static efi_status_t EFIAPI efi_net_receive
 	*buffer_size = receive_lengths[rx_packet_idx];
 	rx_packet_idx = (rx_packet_idx + 1) % ETH_PACKETS_BATCH_RECV;
 	rx_packet_num--;
-	if (rx_packet_num)
+	if (rx_packet_num) {
+		/*
+		 * Since 'this->int_status' is cleared by efi_net_get_status(),
+		 * if user does wait_for_event(wait_for_packet) and
+		 * efi_net_get_status() again, EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT
+		 * is not set even if 'wait_for_packet' is ready.
+		 * Set EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT again here.
+		 */
+		this->int_status |= EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
 		wait_for_packet->is_signaled = true;
-	else
+	} else {
 		this->int_status &= ~EFI_SIMPLE_NETWORK_RECEIVE_INTERRUPT;
+	}
 out:
 	return EFI_EXIT(ret);
 }