From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrei Borzenkov <arvidjaar@gmail.com>
Date: Thu, 7 May 2015 20:37:17 +0300
Subject: [PATCH] efinet: open Simple Network Protocol exclusively

EDK2 network stack is based on Managed Network Protocol which is layered
on top of Simple Management Protocol and does background polling. This
polling races with grub for received (and probably trasmitted) packets
which causes either serious slowdown or complete failure to load files.

Open SNP device exclusively.  This destroys all child MNP instances and
stops background polling.

Exclusive open cannot be done when enumerating cards, as it would destroy
PXE information we need to autoconfigure interface; and it cannot be done
during autoconfiguration as we need to do it for non-PXE boot as well. So
move SNP open to card ->open method and add matching ->close to clean up.

Based on patch from Mark Salter <msalter@redhat.com>

Also-By: Mark Salter <msalter@redhat.com>
Closes: 41731
---
 grub-core/net/drivers/efi/efinet.c | 46 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index caa7b50228b..6a1dd1f9dff 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -142,9 +142,55 @@ get_card_packet (struct grub_net_card *dev)
   return nb;
 }
 
+static grub_err_t
+open_card (struct grub_net_card *dev)
+{
+  grub_efi_simple_network_t *net;
+
+  /* Try to reopen SNP exlusively to close any active MNP protocol instance
+     that may compete for packet polling
+   */
+  net = grub_efi_open_protocol (dev->efi_handle, &net_io_guid,
+				GRUB_EFI_OPEN_PROTOCOL_BY_EXCLUSIVE);
+  if (net)
+    {
+      if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
+	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net start failed",
+			   dev->name);
+
+      if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: card stopped",
+			   dev->name);
+
+      if (net->mode->state == GRUB_EFI_NETWORK_STARTED
+	  && efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net initialize failed",
+			   dev->name);
+
+      efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
+		  dev->efi_net, &net_io_guid,
+		  grub_efi_image_handle, dev->efi_handle);
+      dev->efi_net = net;
+    }
+
+  /* If it failed we just try to run as best as we can */
+  return GRUB_ERR_NONE;
+}
+
+static void
+close_card (struct grub_net_card *dev)
+{
+  efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
+	      dev->efi_net, &net_io_guid,
+	      grub_efi_image_handle, dev->efi_handle);
+}
+
 static struct grub_net_card_driver efidriver =
   {
     .name = "efinet",
+    .open = open_card,
+    .close = close_card,
     .send = send_card_buffer,
     .recv = get_card_packet
   };