linux-kernel - [PATCH] MSI: check for BIOS assigned addresses

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1236352309.31604.2.camel@localhost.localdomain>
Date:	Fri, 06 Mar 2009 10:11:49 -0500
From:	Daniel Yeisley <dan.yeisley@...sys.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org
Subject: [PATCH] MSI: check for BIOS assigned addresses

When creating MSI addresses the kernel makes them up and writes them to
the hardware without first checking for what the system BIOS may have
assigned.  The patch below checks for already assigned values, and
leaves them alone if they exist. 


Signed-off-by: Dan Yeisley <dan.yeisley@...sys.com>

---
diff -Naurp linux-2.6.29-rc5/arch/x86/kernel/io_apic.c linux-2.6.29-rc5-dpy/arch/x86/kernel/io_apic.c
--- linux-2.6.29-rc5/arch/x86/kernel/io_apic.c	2009-02-13 18:31:30.000000000 -0500
+++ linux-2.6.29-rc5-dpy/arch/x86/kernel/io_apic.c	2009-03-04 08:25:30.000000000 -0500
@@ -3258,6 +3258,7 @@ static int msi_compose_msg(struct pci_de
 	struct irq_cfg *cfg;
 	int err;
 	unsigned dest;
+	struct irq_desc *desc = irq_to_desc(irq);
 
 	cfg = irq_cfg(irq);
 	err = assign_irq_vector(irq, cfg, TARGET_CPUS);
@@ -3265,6 +3266,8 @@ static int msi_compose_msg(struct pci_de
 		return err;
 
 	dest = cpu_mask_to_apicid_and(cfg->domain, TARGET_CPUS);
+	
+	read_msi_msg_desc(desc, msg);
 
 #ifdef CONFIG_INTR_REMAP
 	if (irq_remapped(irq)) {
@@ -3295,17 +3298,18 @@ static int msi_compose_msg(struct pci_de
 	} else
 #endif
 	{
-		msg->address_hi = MSI_ADDR_BASE_HI;
-		msg->address_lo =
-			MSI_ADDR_BASE_LO |
-			((INT_DEST_MODE == 0) ?
-				MSI_ADDR_DEST_MODE_PHYSICAL:
-				MSI_ADDR_DEST_MODE_LOGICAL) |
-			((INT_DELIVERY_MODE != dest_LowestPrio) ?
-				MSI_ADDR_REDIRECTION_CPU:
-				MSI_ADDR_REDIRECTION_LOWPRI) |
-			MSI_ADDR_DEST_ID(dest);
-
+		if (!msg->address_hi && !msg->address_lo) {
+			msg->address_hi = MSI_ADDR_BASE_HI;
+			msg->address_lo = 
+				MSI_ADDR_BASE_LO |
+				((INT_DEST_MODE == 0) ?
+					MSI_ADDR_DEST_MODE_PHYSICAL:
+					MSI_ADDR_DEST_MODE_LOGICAL) |
+				((INT_DELIVERY_MODE != dest_LowestPrio) ?
+					MSI_ADDR_REDIRECTION_CPU:
+					MSI_ADDR_REDIRECTION_LOWPRI) |
+				MSI_ADDR_DEST_ID(dest); 
+		}
 		msg->data =
 			MSI_DATA_TRIGGER_EDGE |
 			MSI_DATA_LEVEL_ASSERT |
@@ -3440,11 +3444,13 @@ static int setup_msi_irq(struct pci_dev 
 	int ret;
 	struct msi_msg msg;
 
+	set_irq_msi(irq, msidesc);
 	ret = msi_compose_msg(dev, irq, &msg);
-	if (ret < 0)
+	if (ret < 0) {
+		set_irq_msi(irq, NULL);
 		return ret;
+	}
 
-	set_irq_msi(irq, msidesc);
 	write_msi_msg(irq, &msg);
 
 #ifdef CONFIG_INTR_REMAP


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/