Module Name:    src
Committed By:   msaitoh
Date:           Tue Jun 18 10:06:49 UTC 2019

Modified Files:
        src/sys/arch/x86/pci: msipic.c

Log Message:
 Add note about the case of PCI_MSI_MDATA[64] is 16bit.


To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/arch/x86/pci/msipic.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/arch/x86/pci/msipic.c
diff -u src/sys/arch/x86/pci/msipic.c:1.15 src/sys/arch/x86/pci/msipic.c:1.16
--- src/sys/arch/x86/pci/msipic.c:1.15	Mon Jun 17 06:38:29 2019
+++ src/sys/arch/x86/pci/msipic.c	Tue Jun 18 10:06:49 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: msipic.c,v 1.15 2019/06/17 06:38:29 msaitoh Exp $	*/
+/*	$NetBSD: msipic.c,v 1.16 2019/06/18 10:06:49 msaitoh Exp $	*/
 
 /*
  * Copyright (c) 2015 Internet Initiative Japan Inc.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: msipic.c,v 1.15 2019/06/17 06:38:29 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: msipic.c,v 1.16 2019/06/18 10:06:49 msaitoh Exp $");
 
 #include "opt_intrdebug.h"
 
@@ -388,6 +388,15 @@ msi_addroute(struct pic *pic, struct cpu
 	data = __SHIFTIN(idt_vec, LAPIC_VECTOR_MASK)
 		| LAPIC_TRIGMODE_EDGE | LAPIC_DLMODE_FIXED;
 
+	/*
+	 * The size of the message data register is 16bit if the extended
+	 * message data is not implemented. If it's 16bit and the per-vector
+	 * masking is not capable, the location of the upper 16bit is out of
+	 * the MSI capability structure's range. The PCI spec says the upper
+	 * 16bit is driven to 0 if the message data register is 16bit. It's the
+	 * spec, so it's OK just to write it regardless of the value of the
+	 * upper 16bit.
+	 */
 	ctl = pci_conf_read(pc, tag, off + PCI_MSI_CTL);
 	if (ctl & PCI_MSI_CTL_64BIT_ADDR) {
 		pci_conf_write(pc, tag, off + PCI_MSI_MADDR64_LO, addr);

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