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 <bruss...@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 <bruss...@brocade.com>
> > > Signed-off-by: Luca Boccassi <bl...@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
