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.
> > @@ -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.
--
Kind regards,
Luca Boccassi
