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From: Tiwei Bie <tiwei.bie@intel.com>
To: Luca Boccassi <bluca@debian.org>
Cc: dev@dpdk.org, maxime.coquelin@redhat.com, zhihong.wang@intel.com,
	bruce.richardson@intel.com, brian.russell@intl.att.com
Subject: Re: [dpdk-dev] [PATCH v4 2/2] virtio: fix PCI config err handling
Date: Tue, 28 Aug 2018 14:47:46 +0800
Message-ID: <20180828064746.GB80296@fbsd.sh.intel.com> (raw)
In-Reply-To: <1535388776.8636.15.camel@debian.org>

On Mon, Aug 27, 2018 at 05:52:56PM +0100, Luca Boccassi wrote:
> On Mon, 2018-08-27 at 13:29 +0800, Tiwei Bie wrote:
> > On Fri, Aug 24, 2018 at 06:14:20PM +0100, Luca Boccassi wrote:
> > > From: Brian Russell <brussell@brocade.com>
> > > 
> > > In virtio_read_caps and vtpci_msix_detect, rte_pci_read_config
> > > returns
> > > the number of bytes read from PCI config or < 0 on error.
> > > If less than the expected number of bytes are read then log the
> > > failure and return rather than carrying on with garbage.
> > > 
> > > Fixes: 6ba1f63b5ab0 ("virtio: support specification 1.0")
> > > 
> > > Signed-off-by: Brian Russell <brussell@brocade.com>
> > > Signed-off-by: Luca Boccassi <bluca@debian.org>
> > > ---
> > > v2: handle additional rte_pci_read_config incomplete reads
> > > v3: do not handle rte_pci_read_config of virtio cap, added in v2,
> > >     as it's less clear what the right thing to do there is
> > > v4: do a more robust check - first check what the vendor is, and
> > >     skip the cap entirely if it's not what we are looking for.
> > > 
> > >  drivers/net/virtio/virtio_pci.c | 57 ++++++++++++++++++++++++-----
> > > ----
> > >  1 file changed, 42 insertions(+), 15 deletions(-)
> > > 
> > > diff --git a/drivers/net/virtio/virtio_pci.c
> > > b/drivers/net/virtio/virtio_pci.c
> > > index 6bd22e54a6..cfefa9789b 100644
> > > --- a/drivers/net/virtio/virtio_pci.c
> > > +++ b/drivers/net/virtio/virtio_pci.c
> > > @@ -567,16 +567,30 @@ virtio_read_caps(struct rte_pci_device *dev,
> > > struct virtio_hw *hw)
> > >  	}
> > >  
> > >  	ret = rte_pci_read_config(dev, &pos, 1,
> > > PCI_CAPABILITY_LIST);
> > > -	if (ret < 0) {
> > > -		PMD_INIT_LOG(DEBUG, "failed to read pci capability
> > > list");
> > > +	if (ret != 1) {
> > > +		PMD_INIT_LOG(DEBUG,
> > > +			     "failed to read pci capability list,
> > > ret %d", ret);
> > >  		return -1;
> > >  	}
> > >  
> > >  	while (pos) {
> > > +		ret = rte_pci_read_config(dev, &cap, 2, pos);
> > > +		if (ret != 2) {
> > > +			PMD_INIT_LOG(DEBUG,
> > > +				     "failed to read pci cap at
> > > pos: %x ret %d",
> > > +				     pos, ret);
> > > +			break;
> > > +		}
> > > +		if (cap.cap_vndr != PCI_CAP_ID_MSIX &&
> > > +				cap.cap_vndr != PCI_CAP_ID_VNDR) {
> > > +			goto next;
> > > +		}
> > > +
> > >  		ret = rte_pci_read_config(dev, &cap, sizeof(cap),
> > > pos);
> > > -		if (ret < 0) {
> > > -			PMD_INIT_LOG(ERR,
> > > -				"failed to read pci cap at pos:
> > > %x", pos);
> > > +		if (ret != sizeof(cap)) {
> > > +			PMD_INIT_LOG(DEBUG,
> > > +				     "failed to read pci cap at
> > > pos: %x ret %d",
> > > +				     pos, ret);
> > >  			break;
> > >  		}
> > >  
> > 
> > It seems that I didn't make myself clear in my previous
> > comments. I mean it's better to handle MSIX cap and virtio
> > cap respectively in this function. Currently we're always
> > reading them as virtio caps. As we are strictly requiring
> > that _read_config() should return the required number of
> > bytes, it's not perfect to require it to return "virtio
> > cap size" of bytes while we're trying to read a MSIX cap.
> > So please change the code to something similar to this:
> 
> Sorry, though you meant in the vtpci_msix_detect function, which I
> changed. Fixed in v5.

Thanks!

> 
> > > @@ -689,25 +703,38 @@ enum virtio_msix_status
> > >  vtpci_msix_detect(struct rte_pci_device *dev)
> > >  {
> > >  	uint8_t pos;
> > > -	struct virtio_pci_cap cap;
> > >  	int ret;
> > >  
> > >  	ret = rte_pci_read_config(dev, &pos, 1,
> > > PCI_CAPABILITY_LIST);
> > > -	if (ret < 0) {
> > > -		PMD_INIT_LOG(DEBUG, "failed to read pci capability
> > > list");
> > > +	if (ret != 1) {
> > > +		PMD_INIT_LOG(DEBUG,
> > > +			     "failed to read pci capability list,
> > > ret %d", ret);
> > >  		return VIRTIO_MSIX_NONE;
> > >  	}
> > >  
> > >  	while (pos) {
> > > -		ret = rte_pci_read_config(dev, &cap, sizeof(cap),
> > > pos);
> > > -		if (ret < 0) {
> > > -			PMD_INIT_LOG(ERR,
> > > -				"failed to read pci cap at pos:
> > > %x", pos);
> > > +		uint8_t cap[2];
> > > +
> > > +		ret = rte_pci_read_config(dev, cap, sizeof(cap),
> > > pos);
> > > +		if (ret != sizeof(cap)) {
> > > +			PMD_INIT_LOG(DEBUG,
> > > +				     "failed to read pci cap at
> > > pos: %x ret %d",
> > > +				     pos, ret);
> > >  			break;
> > >  		}
> > >  
> > > -		if (cap.cap_vndr == PCI_CAP_ID_MSIX) {
> > > -			uint16_t flags = ((uint16_t *)&cap)[1];
> > > +		if (cap[0] == PCI_CAP_ID_MSIX) {
> > > +			uint16_t flags;
> > > +
> > > +			ret = rte_pci_read_config(dev, &flags,
> > > sizeof(flags),
> > > +					pos + sizeof(cap));
> > > +			if (ret != sizeof(flags)) {
> > > +				PMD_INIT_LOG(DEBUG,
> > > +					     "failed to read pci
> > > cap at pos:"
> > > +					     " %x ret %d", pos +
> > > sizeof(cap),
> > 
> > There is a build error:
> > 
> > In file included from drivers/net/virtio/virtio_pci.c:15:
> > drivers/net/virtio/virtio_pci.c: In function ‘vtpci_msix_detect’:
> > drivers/net/virtio/virtio_logs.h:13:3: error: format ‘%x’ expects
> > argument of type ‘unsigned int’, but argument 5 has type ‘long
> > unsigned int’ [-Werror=format=]
> >    "%s(): " fmt "\n", __func__, ##args)
> >    ^~~~~~~~
> > drivers/net/virtio/virtio_pci.c:732:5: note: in expansion of macro
> > ‘PMD_INIT_LOG’
> >      PMD_INIT_LOG(DEBUG,
> >      ^~~~~~~~~~~~
> > drivers/net/virtio/virtio_pci.c:734:14: note: format string is
> > defined here
> >            " %x ret %d", pos + sizeof(cap),
> >              ~^
> >              %lx
> 
> Ok, changed to %lx - which GCC version was that with? Didn't get any
> warning with 6.3 on Debian 9.

I saw this with gcc (Debian 8.2.0-4) 8.2.0 on Debian sid.
I also saw similar warnings with clang version 6.0.0
(tags/RELEASE_600/final 326565) on FreeBSD 11.2

> 
> -- 
> Kind regards,
> Luca Boccassi

  reply	other threads:[~2018-08-28  6:50 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-14 14:30 [dpdk-dev] [PATCH 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-14 14:30 ` [dpdk-dev] [PATCH 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-15  3:11   ` Tiwei Bie
2018-08-15  9:50     ` Luca Boccassi
2018-08-16  6:46       ` Tiwei Bie
2018-08-16 10:27         ` Luca Boccassi
2018-08-16 18:47 ` [dpdk-dev] [PATCH 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-16 18:47   ` [dpdk-dev] [PATCH 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-16 18:49     ` Luca Boccassi
2018-08-20  8:18       ` Tiwei Bie
2018-08-20 16:45         ` Luca Boccassi
2018-08-21  2:40           ` Tiwei Bie
2018-08-23 12:52             ` Luca Boccassi
2018-08-24  4:23               ` Tiwei Bie
2018-08-24 17:14                 ` Luca Boccassi
2018-08-20 16:44   ` [dpdk-dev] [PATCH v3 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-20 16:44     ` [dpdk-dev] [PATCH v3 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-24 17:14     ` [dpdk-dev] [PATCH v4 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-24 17:14       ` [dpdk-dev] [PATCH v4 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-27  5:29         ` Tiwei Bie
2018-08-27 16:52           ` Luca Boccassi
2018-08-28  6:47             ` Tiwei Bie [this message]
2018-08-27 16:52       ` [dpdk-dev] [PATCH v5 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-27 16:52         ` [dpdk-dev] [PATCH v5 2/2] virtio: fix PCI config err handling Luca Boccassi
2018-08-28  6:43           ` Tiwei Bie
2018-08-28 10:14             ` Luca Boccassi
2018-08-28 10:12         ` [dpdk-dev] [PATCH v6 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-08-28 10:12           ` [dpdk-dev] [PATCH v6 2/2] net/virtio: fix PCI config err handling Luca Boccassi
2018-10-11 10:27             ` Thomas Monjalon
2018-10-11 10:53               ` Luca Boccassi
2018-10-11 13:01                 ` Tiwei Bie
2018-10-28 23:55                   ` Thomas Monjalon
2018-10-17  9:58           ` [dpdk-dev] [PATCH v6 1/2] bus/pci: harmonize and document rte_pci_read_config return value Luca Boccassi
2018-10-17 10:57             ` Bruce Richardson

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