On Thu, 10 Oct 2024, Michał Winiarski wrote:
> Similar to regular resizable BAR, VF BAR can also be resized, e.g. by
> the system firmware, or the PCI subsystem itself.
> Add the capability ID and restore it as a part of IOV state.
> See PCIe r4.0, sec 9.3.7.4.
>
> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx>
> ---
> drivers/pci/iov.c | 29 ++++++++++++++++++++++++++++-
> include/uapi/linux/pci_regs.h | 1 +
> 2 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index aaa33e8dc4c97..fd5c059b29c13 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -7,6 +7,7 @@
> * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@xxxxxxxxx>
> */
>
> +#include <linux/bitfield.h>
> #include <linux/pci.h>
> #include <linux/slab.h>
> #include <linux/export.h>
> @@ -862,6 +863,30 @@ static void sriov_release(struct pci_dev *dev)
> dev->sriov = NULL;
> }
>
> +static void sriov_restore_vf_rebar_state(struct pci_dev *dev)
> +{
> + unsigned int pos, nbars, i;
> + u32 ctrl;
> +
> + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VF_REBAR);
> + if (!pos)
> + return;
> +
> + pci_read_config_dword(dev, pos + PCI_REBAR_CTRL, &ctrl);
> + nbars = FIELD_GET(PCI_REBAR_CTRL_NBAR_MASK, ctrl);
> +
> + for (i = 0; i < nbars; i++, pos += 8) {
> + int bar_idx, size;
> +
> + pci_read_config_dword(dev, pos + PCI_REBAR_CTRL, &ctrl);
> + bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX;
Use FIELD_GET().
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
--
i.
> + size = pci_rebar_bytes_to_size(dev->sriov->barsz[bar_idx]);
> + ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
> + ctrl |= FIELD_PREP(PCI_REBAR_CTRL_BAR_SIZE, size);
> + pci_write_config_dword(dev, pos + PCI_REBAR_CTRL, ctrl);
> + }
> +}
> +
> static void sriov_restore_state(struct pci_dev *dev)
> {
> int i;
> @@ -1021,8 +1046,10 @@ resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
> */
> void pci_restore_iov_state(struct pci_dev *dev)
> {
> - if (dev->is_physfn)
> + if (dev->is_physfn) {
> + sriov_restore_vf_rebar_state(dev);
> sriov_restore_state(dev);
> + }
> }
>
> /**
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 12323b3334a9c..a0cf701c4c3af 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -740,6 +740,7 @@
> #define PCI_EXT_CAP_ID_L1SS 0x1E /* L1 PM Substates */
> #define PCI_EXT_CAP_ID_PTM 0x1F /* Precision Time Measurement */
> #define PCI_EXT_CAP_ID_DVSEC 0x23 /* Designated Vendor-Specific */
> +#define PCI_EXT_CAP_ID_VF_REBAR 0x24 /* VF Resizable BAR */
> #define PCI_EXT_CAP_ID_DLF 0x25 /* Data Link Feature */
> #define PCI_EXT_CAP_ID_PL_16GT 0x26 /* Physical Layer 16.0 GT/s */
> #define PCI_EXT_CAP_ID_NPEM 0x29 /* Native PCIe Enclosure Management */
>
