On Thu, 10 Oct 2024, Michał Winiarski wrote:
> Similar to regular resizable BAR, VF BAR can also be resized.
> The structures are very similar, which means we can reuse most of the
> implementation. See PCIe r4.0, sec 9.3.7.4.
>
> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx>
> ---
> drivers/pci/iov.c | 20 ++++++++++++++++++++
> drivers/pci/pci.c | 9 ++++++++-
> drivers/pci/pci.h | 8 ++++++++
> drivers/pci/setup-res.c | 33 ++++++++++++++++++++++++++++-----
> 4 files changed, 64 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index fd5c059b29c13..591a3eae1618a 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -154,6 +154,26 @@ resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
> return dev->sriov->barsz[resno - PCI_IOV_RESOURCES];
> }
>
> +void pci_iov_resource_set_size(struct pci_dev *dev, int resno, resource_size_t size)
> +{
> + if (!pci_resource_is_iov(resno)) {
> + pci_warn(dev, "%s is not an IOV resource\n",
> + pci_resource_name(dev, resno));
> + return;
> + }
> +
> + dev->sriov->barsz[resno - PCI_IOV_RESOURCES] = size;
> +}
> +
> +bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
> +{
> + u16 cmd;
> +
> + pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd);
> +
> + return cmd & PCI_SRIOV_CTRL_MSE;
> +}
> +
> static void pci_read_vf_config_common(struct pci_dev *virtfn)
> {
> struct pci_dev *physfn = virtfn->physfn;
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7d85c04fbba2a..788ae61731213 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3718,10 +3718,17 @@ void pci_acs_init(struct pci_dev *dev)
> */
> static int pci_rebar_find_pos(struct pci_dev *pdev, int bar)
> {
> + int cap = PCI_EXT_CAP_ID_REBAR;
> unsigned int pos, nbars, i;
> u32 ctrl;
>
> - pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR);
> +#ifdef CONFIG_PCI_IOV
> + if (pci_resource_is_iov(bar)) {
> + cap = PCI_EXT_CAP_ID_VF_REBAR;
> + bar -= PCI_IOV_RESOURCES;
> + }
> +#endif
Perhaps abstracting bar -= PCI_IOV_RESOURCES too into some static inline
function would be useful so you could drop the ifdefs. That calculation
seems to be done in few places besides this one.
> + pos = pci_find_ext_capability(pdev, cap);
> if (!pos)
> return -ENOTSUPP;
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index c55f2d7a4f37e..e15fd8fe0f81f 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -584,6 +584,8 @@ static inline bool pci_resource_is_iov(int resno)
> {
> return resno >= PCI_IOV_RESOURCES && resno <= PCI_IOV_RESOURCE_END;
> }
> +void pci_iov_resource_set_size(struct pci_dev *dev, int resno, resource_size_t size);
> +bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev);
> extern const struct attribute_group sriov_pf_dev_attr_group;
> extern const struct attribute_group sriov_vf_dev_attr_group;
> #else
> @@ -607,6 +609,12 @@ static inline bool pci_resource_is_iov(int resno)
> {
> return false;
> }
> +static inline void pci_iov_resource_set_size(struct pci_dev *dev, int resno,
> + resource_size_t size) { }
> +static inline bool pci_iov_is_memory_decoding_enabled(struct pci_dev *dev)
> +{
> + return false;
> +}
> #endif /* CONFIG_PCI_IOV */
>
> #ifdef CONFIG_PCIE_PTM
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index e2cf79253ebda..95a13a5fa379c 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -425,13 +425,37 @@ void pci_release_resource(struct pci_dev *dev, int resno)
> }
> EXPORT_SYMBOL(pci_release_resource);
>
> +static bool pci_resize_is_memory_decoding_enabled(struct pci_dev *dev, int resno)
> +{
> + u16 cmd;
> +
> + if (pci_resource_is_iov(resno))
> + return pci_iov_is_memory_decoding_enabled(dev);
> +
> + pci_read_config_word(dev, PCI_COMMAND, &cmd);
> +
> + return cmd & PCI_COMMAND_MEMORY;
> +}
> +
> +static void pci_resize_resource_set_size(struct pci_dev *dev, int resno, int size)
> +{
> + resource_size_t res_size = pci_rebar_size_to_bytes(size);
> + struct resource *res = dev->resource + resno;
> +
> + if (!pci_resource_is_iov(resno)) {
> + res->end = res->start + res_size - 1;
> + } else {
> + res->end = res->start + res_size * pci_sriov_get_totalvfs(dev) - 1;
I wish Bjorn would pick up my resource_set_{range,size}() series [1] so we
wouldn't need to open-code this resource size calculation everywhere.
> + pci_iov_resource_set_size(dev, resno, res_size);
> + }
> +}
> +
> int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> {
> struct resource *res = dev->resource + resno;
> struct pci_host_bridge *host;
> int old, ret;
> u32 sizes;
> - u16 cmd;
>
> /* Check if we must preserve the firmware's resource assignment */
> host = pci_find_host_bridge(dev->bus);
> @@ -442,8 +466,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> if (!(res->flags & IORESOURCE_UNSET))
> return -EBUSY;
>
> - pci_read_config_word(dev, PCI_COMMAND, &cmd);
> - if (cmd & PCI_COMMAND_MEMORY)
> + if (pci_resize_is_memory_decoding_enabled(dev, resno))
> return -EBUSY;
>
> sizes = pci_rebar_get_possible_sizes(dev, resno);
> @@ -461,7 +484,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> if (ret)
> return ret;
>
> - res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
> + pci_resize_resource_set_size(dev, resno, size);
>
> /* Check if the new config works by trying to assign everything. */
> if (dev->bus->self) {
> @@ -473,7 +496,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
>
> error_resize:
> pci_rebar_set_size(dev, resno, old);
> - res->end = res->start + pci_rebar_size_to_bytes(old) - 1;
> + pci_resize_resource_set_size(dev, resno, old);
> return ret;
> }
> EXPORT_SYMBOL(pci_resize_resource);
>
[1] https://patchwork.kernel.org/project/linux-pci/patch/20240614100606.15830-2-ilpo.jarvinen@xxxxxxxxxxxxxxx/
--
i.
