Linux Virtualization - Jan 2015 - [PATCH v3 00/16] virtio-pci: towards virtio 1.0 guest support

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 at 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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On Mon, Jan 19, 2015 at 12:07:00PM +0100, Gerd Hoffmann
wrote:
>   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?
Wow! And I made the same bug in the guest too.
Good catch, will fix both up.
> 
> Also note:
> 
> [root at 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
> 
Just in case :) I'll make it smaller, will address your concerns
about BAR size in a simple way.

> >From 0d5d99c20b079c986128c3d98c4bbaba51ebe65c Mon Sep 17 00:00:00 2001
> From: Gerd Hoffmann <kraxel at 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 at 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
>

On Mon, Jan 19, 2015 at 12:07:00PM +0100, Gerd Hoffmann
wrote:
>   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?
Thanks a lot for the report, and the tool!
I sent patches to fix this all up.
You can try my qemu and linux virtio-net branches now,
they should be spec compliant.

-- 
MST

Hi,
> > 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?
> 
> Thanks a lot for the report, and the tool!
pciutils patch needs an update too (because I've made it decode the
broken qemu capabilities).  Will come as separate mail with proper
commit message in a moment.
> I sent patches to fix this all up.
> You can try my qemu and linux virtio-net branches now,
> they should be spec compliant.
Yep, much better.  caps match spec, the system boots fine from
virtio-scsi, and the nfs-mounts (using virtio-net) are there too.

cheers,
  Gerd