From: Miroslav Rezanina <mrezanin@redhat.com>
Date: Tue, 15 Dec 2009 14:00:43 -0500
Subject: [iscsi] fix install panic w/xen iSCSI boot device
Message-id: <2005263104.1650781260885643859.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
Patchwork-id: 21953
O-Subject: [RHEL5.5 Patch] BZ512991 kernel panic during install using iSCSI
	boot device with Xen
Bugzilla: 512991
RH-Acked-by: Andrew Jones <drjones@redhat.com>

BZ512991 - kernel panic during install using iSCSI boot device with Xen
(https://bugzilla.redhat.com/show_bug.cgi?id=512991)

Problem:
When booting xen kernel from hw iscsi device using iBFT feature, kernel panics and
report "No iBFT found". Non-xen kernel boots successfully.

Reason:
Xen kernel do not scan memory for iBFT (iscsi Boot Firmware Table). This was probably
removed as scanning cause crash.

Solution:
In xen kernel, paging inicialization has to be finished to be able scan memory for iBFT.
Calling scanning function later is done without crash. However, iBFT is still not found.
This is due to wrong translation function used to get address. isa_bus_to_virt has to be
used instead of phys_to_virt.

Upstream status:
Linux upstream commit ed3c661448a1b4b0b07c0a0d3c6e8a19c7d0ffd7 introduce proper address
translation. Due to different code structure, patch is not applicable to upstream.

Patch:
------

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/arch/i386/kernel/setup-xen.c b/arch/i386/kernel/setup-xen.c
index dd676a0..a567e6a 100644
--- a/arch/i386/kernel/setup-xen.c
+++ b/arch/i386/kernel/setup-xen.c
@@ -42,6 +42,7 @@
 #include <linux/efi.h>
 #include <linux/init.h>
 #include <linux/edd.h>
+#include <linux/iscsi_ibft.h>
 #include <linux/nodemask.h>
 #include <linux/kexec.h>
 #include <linux/crash_dump.h>
@@ -1752,6 +1753,7 @@ void __init setup_arch(char **cmdline_p)
 	smp_alloc_memory(); /* AP processor realmode stacks in low memory*/
 #endif
 	paging_init();
+	reserve_ibft_region();
 	remapped_pgdat_init();
 	sparse_init();
 	zone_sizes_init();
diff --git a/arch/x86_64/kernel/setup-xen.c b/arch/x86_64/kernel/setup-xen.c
index 25c0dad..78cad9f 100644
--- a/arch/x86_64/kernel/setup-xen.c
+++ b/arch/x86_64/kernel/setup-xen.c
@@ -37,6 +37,7 @@
 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <linux/kallsyms.h>
+#include <linux/iscsi_ibft.h>
 #include <linux/edd.h>
 #include <linux/mmzone.h>
 #include <linux/kexec.h>
@@ -796,6 +797,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 	paging_init();
+	reserve_ibft_region();
 #ifdef CONFIG_X86_LOCAL_APIC
 	/*
 	 * Find and reserve possible boot-time SMP configuration:
diff --git a/drivers/firmware/iscsi_ibft.c b/drivers/firmware/iscsi_ibft.c
index 392d7d6..3d6e274 100644
--- a/drivers/firmware/iscsi_ibft.c
+++ b/drivers/firmware/iscsi_ibft.c
@@ -932,7 +932,7 @@ static int __init ibft_init(void)
 
 	if (ibft_addr) {
 		printk(KERN_INFO "iBFT detected at 0x%lx.\n",
-		       virt_to_phys((void *)ibft_addr));
+		       isa_bus_to_virt((void *)ibft_addr));
 
 		rc = ibft_check_device();
 		if (rc)
diff --git a/drivers/firmware/iscsi_ibft_find.c b/drivers/firmware/iscsi_ibft_find.c
index 8ef433a..45a7818 100644
--- a/drivers/firmware/iscsi_ibft_find.c
+++ b/drivers/firmware/iscsi_ibft_find.c
@@ -63,10 +63,10 @@ void __init reserve_ibft_region(void)
 		 * so skip that area */
 		if (pos == VGA_MEM)
 			pos += VGA_SIZE;
-		virt = phys_to_virt(pos);
+		virt = isa_bus_to_virt(pos);
 		if (memcmp(virt, IBFT_SIGN, IBFT_SIGN_LEN) == 0) {
 			unsigned long *addr =
-			    (unsigned long *)phys_to_virt(pos + 4);
+			    (unsigned long *)isa_bus_to_virt(pos + 4);
 			len = *addr;
 			/* if the length of the table extends past 1M,
 			 * the table cannot be valid. */