Re: [PATCH v3 00/16] virtio-pci: towards virtio 1.0 guest support

[Gerd Hoffmann <kraxel@redhat.com>]

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  Hi,

> BTW: is there a tool (or pciutils patch) which can decode the virtio
> capabilities?

Searched for a patch today, and all google found me was this mail asking
for one :-o

So I went ahead and coded one up.  Attached.

While hacking it up I've noticed spec doesn't match reality.  The
"Virtio Structure PCI Capabilities" section here ...

http://docs.oasis-open.org/virtio/virtio/v1.0/cs01/virtio-v1.0-cs01.html#x1-690004

... doesn't match what qemu is doing.  Huh?


Also note:

[root@fedora ~]# ~kraxel/projects/pciutils/lspci -vvsa
00:0a.0 Communication controller: Red Hat, Inc Virtio console
[ ... ]
	Capabilities: [64] VirtIO: Notify
		BAR=2 offset=00003000 size=00400000
		multiplier=00010000
[ ... ]

Why multiplier is 64k instead of 4k?  Just a tyops?


cheers,
  Gerd


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>From 0d5d99c20b079c986128c3d98c4bbaba51ebe65c Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 19 Jan 2015 11:46:37 +0100
Subject: [PATCH] add virtio vendor caps

---
 Makefile         |  2 +-
 ls-caps-vendor.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ls-caps.c        |  9 ++++++++-
 lspci.h          |  4 ++++
 4 files changed, 70 insertions(+), 2 deletions(-)
 create mode 100644 ls-caps-vendor.c

diff --git a/Makefile b/Makefile
index 8d49afa..39a07d1 100644
--- a/Makefile
+++ b/Makefile
@@ -69,7 +69,7 @@ force:
 lib/config.h lib/config.mk:
 	cd lib && ./configure
 
-lspci: lspci.o ls-vpd.o ls-caps.o ls-ecaps.o ls-kernel.o ls-tree.o ls-map.o common.o lib/$(PCILIB)
+lspci: lspci.o ls-vpd.o ls-caps.o ls-caps-vendor.o ls-ecaps.o ls-kernel.o ls-tree.o ls-map.o common.o lib/$(PCILIB)
 setpci: setpci.o common.o lib/$(PCILIB)
 
 LSPCIINC=lspci.h pciutils.h $(PCIINC)
diff --git a/ls-caps-vendor.c b/ls-caps-vendor.c
new file mode 100644
index 0000000..5f8b3e1
--- /dev/null
+++ b/ls-caps-vendor.c
@@ -0,0 +1,57 @@
+/*
+ *	The PCI Utilities -- Show Vendor-specific Capabilities
+ *
+ *	Copyright (c) 2014 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "lspci.h"
+
+void
+show_vendor_caps_virtio(struct device *d, int where, int cap)
+{
+  int length = BITS(cap, 0, 8);
+  int type = BITS(cap, 8, 5);
+  int bar = BITS(cap, 13, 3);
+  char *tname;
+
+  if (length < 12)
+    return;
+  if (!config_fetch(d, where, length))
+    return;
+
+  switch (type) {
+  case 1:
+      tname = "CommonCfg";
+      break;
+  case 2:
+      tname = "Notify";
+      break;
+  case 3:
+      tname = "ISR";
+      break;
+  case 4:
+      tname = "DeviceCfg";
+      break;
+  default:
+      tname = "<unknown>";
+      break;
+  }
+
+  printf("VirtIO: %s\n", tname);
+
+  if (verbose < 2)
+    return;
+
+  printf("\t\tBAR=%d offset=%08x size=%08x\n", bar,
+         get_conf_long(d, where+4),
+         get_conf_long(d, where+8));
+  if (type != 2 || length < 16)
+    return;
+  printf("\t\tmultiplier=%08x\n",
+         get_conf_long(d, where+12));
+}
diff --git a/ls-caps.c b/ls-caps.c
index 7de55ef..438b580 100644
--- a/ls-caps.c
+++ b/ls-caps.c
@@ -1315,7 +1315,14 @@ show_caps(struct device *d, int where)
 	      cap_ht(d, where, cap);
 	      break;
 	    case PCI_CAP_ID_VNDR:
-	      printf("Vendor Specific Information: Len=%02x <?>\n", BITS(cap, 0, 8));
+              switch (get_conf_word(d, PCI_VENDOR_ID)) {
+              case 0x1af4: /* Red Hat, devices 0x1000 -> 0x107f are virtio */
+                show_vendor_caps_virtio(d, where, cap);
+                break;
+              default:
+                printf("Vendor Specific Information: Len=%02x <?>\n", BITS(cap, 0, 8));
+                break;
+              }
 	      break;
 	    case PCI_CAP_ID_DBG:
 	      cap_debug_port(cap);
diff --git a/lspci.h b/lspci.h
index 86429b2..5ca9899 100644
--- a/lspci.h
+++ b/lspci.h
@@ -70,6 +70,10 @@ void show_caps(struct device *d, int where);
 
 void show_ext_caps(struct device *d);
 
+/* ls-caps-vendor.c */
+
+void show_vendor_caps_virtio(struct device *d, int where, int cap);
+
 /* ls-kernel.c */
 
 void show_kernel_machine(struct device *d UNUSED);
-- 
1.8.3.1