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:
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) {
/* Transitional devices would also have this capability,
* that's why we also check if msix is enabled.
* 1st byte is cap ID; 2nd byte is the position of next
* cap; next two bytes are the flags.
*/
uint16_t flags;
ret = rte_pci_read_config(dev, &flags, sizeof(flags),
pos + 2);
if (ret != sizeof(flags)) {
PMD_INIT_LOG(DEBUG,
"failed to read pci cap at pos: %x ret
%d",
pos + 2, ret);
break;
}
if (flags & PCI_MSIX_ENABLE)
hw->use_msix = VIRTIO_MSIX_ENABLED;
else
hw->use_msix = VIRTIO_MSIX_DISABLED;
}
if (cap.cap_vndr != PCI_CAP_ID_VNDR) {
PMD_INIT_LOG(DEBUG,
"[%2x] skipping non VNDR cap id: %02x",
pos, cap.cap_vndr);
goto next;
}
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;
}
PMD_INIT_LOG(DEBUG,
"[%2x] cfg type: %u, bar: %u, offset: %04x, len: %u",
pos, cap.cfg_type, cap.bar, cap.offset, cap.length);
switch (cap.cfg_type) {
......
> @@ -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
> + ret);
> + break;
> + }
>
> if (flags & PCI_MSIX_ENABLE)
> return VIRTIO_MSIX_ENABLED;
> @@ -715,7 +742,7 @@ vtpci_msix_detect(struct rte_pci_device *dev)
> return VIRTIO_MSIX_DISABLED;
> }
>
> - pos = cap.cap_next;
> + pos = cap[1];
> }
>
> return VIRTIO_MSIX_NONE;
> --
> 2.18.0
>
