Re: [PATCH 1/1][v2] PCI: Support VF resizable BAR

From: Bjorn Helgaas
Date: Fri Jun 07 2024 - 16:40:36 EST

On Fri, Jun 07, 2024 at 01:37:21PM +0200, Christian König wrote:
> I need the original set of patches, e.g. directly use git send-email with my
> mail address.

This worked for me:

$ git checkout -b wip/2406-lianjie-vf-rebar-v2 v6.10-rc1
$ b4 am https://lore.kernel.org/r/20240523071114.2930804-2-Lianjie.Shi@xxxxxxx
$ git am ./v2_20240523_lianjie_shi_pci_vf_resizable_bar.mbx

> Am 07.06.24 um 10:42 schrieb Chang, HaiJun:
> > [AMD Official Use Only - AMD Internal Distribution Only]
> >
> > + Christian to review the VF resizable BAR patch.
> >
> > -----Original Message-----
> > From: Chang, HaiJun
> > Sent: Friday, May 31, 2024 12:26 PM
> > To: Lianjie Shi <Lianjie.Shi@xxxxxxx>; linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Cc: Jiang, Jerry (SW) <Jerry.Jiang@xxxxxxx>; Zhang, Andy <Andy.Zhang@xxxxxxx>; Shi, Lianjie <Lianjie.Shi@xxxxxxx>
> > Subject: RE: [PATCH 1/1][v2] PCI: Support VF resizable BAR
> >
> > Hi, Bjorn and pci driver maintainers
> >
> > Could you review the VF resizable BAR patch?
> >
> > Thanks,
> > HaiJun
> >
> > -----Original Message-----
> > From: Lianjie Shi <Lianjie.Shi@xxxxxxx>
> > Sent: Thursday, May 23, 2024 3:11 PM
> > To: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Cc: Chang, HaiJun <HaiJun.Chang@xxxxxxx>; Jiang, Jerry (SW) <Jerry.Jiang@xxxxxxx>; Zhang, Andy <Andy.Zhang@xxxxxxx>; Shi, Lianjie <Lianjie.Shi@xxxxxxx>
> > Subject: [PATCH 1/1][v2] PCI: Support VF resizable BAR
> >
> > Add support for VF resizable BAR PCI extended cap.
> > Similar to regular BAR, drivers can use pci_resize_resource() to resize an IOV BAR. For each VF, dev->sriov->barsz of the IOV BAR is resized, but the total resource size of the IOV resource should not exceed its original size upon init.
> >
> > Based on following patch series:
> > Link: https://lore.kernel.org/lkml/YbqGplTKl5i%2F1%2FkY@rocinante/T/
> >
> > Signed-off-by: Lianjie Shi <Lianjie.Shi@xxxxxxx>
> > ---
> > drivers/pci/pci.c | 47 ++++++++++++++++++++++++++++++++++-
> > drivers/pci/setup-res.c | 45 +++++++++++++++++++++++++++------
> > include/uapi/linux/pci_regs.h | 1 +
> > 3 files changed, 85 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e5f243dd4..12f86e00a 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1867,6 +1867,42 @@ static void pci_restore_rebar_state(struct pci_dev *pdev)
> > }
> > }
> >
> > +static void pci_restore_vf_rebar_state(struct pci_dev *pdev) { #ifdef
> > +CONFIG_PCI_IOV
> > + unsigned int pos, nbars, i;
> > + u32 ctrl;
> > + u16 total;
> > +
> > + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_VF_REBAR);
> > + if (!pos)
> > + return;
> > +
> > + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
> > + nbars = FIELD_GET(PCI_REBAR_CTRL_NBAR_MASK, ctrl);
> > +
> > + for (i = 0; i < nbars; i++, pos += 8) {
> > + struct resource *res;
> > + int bar_idx, size;
> > + u64 tmp;
> > +
> > + pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
> > + bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX;
> > + total = pdev->sriov->total_VFs;
> > + if (!total)
> > + return;
> > +
> > + res = pdev->resource + bar_idx + PCI_IOV_RESOURCES;
> > + tmp = resource_size(res);
> > + do_div(tmp, total);
> > + size = pci_rebar_bytes_to_size(tmp);
> > + ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
> > + ctrl |= FIELD_PREP(PCI_REBAR_CTRL_BAR_SIZE, size);
> > + pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
> > + }
> > +#endif
> > +}
> > +
> > /**
> > * pci_restore_state - Restore the saved state of a PCI device
> > * @dev: PCI device that we're dealing with @@ -1882,6 +1918,7 @@ void pci_restore_state(struct pci_dev *dev)
> > pci_restore_ats_state(dev);
> > pci_restore_vc_state(dev);
> > pci_restore_rebar_state(dev);
> > + pci_restore_vf_rebar_state(dev);
> > pci_restore_dpc_state(dev);
> > pci_restore_ptm_state(dev);
> >
> > @@ -3677,10 +3714,18 @@ 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 (bar >= PCI_IOV_RESOURCES) {
> > + cap = PCI_EXT_CAP_ID_VF_REBAR;
> > + bar -= PCI_IOV_RESOURCES;
> > + }
> > +#endif
> > +
> > + pos = pci_find_ext_capability(pdev, cap);
> > if (!pos)
> > return -ENOTSUPP;
> >
> > diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index c6d933ddf..d978a2ccf 100644
> > --- a/drivers/pci/setup-res.c
> > +++ b/drivers/pci/setup-res.c
> > @@ -427,13 +427,32 @@ void pci_release_resource(struct pci_dev *dev, int resno) } EXPORT_SYMBOL(pci_release_resource);
> >
> > +static int pci_memory_decoding(struct pci_dev *dev, int resno) {
> > + u16 cmd;
> > +
> > +#ifdef CONFIG_PCI_IOV
> > + if (resno >= PCI_IOV_RESOURCES) {
> > + pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd);
> > + if (cmd & PCI_SRIOV_CTRL_MSE)
> > + return -EBUSY;
> > + else
> > + return 0;
> > + }
> > +#endif
> > + pci_read_config_word(dev, PCI_COMMAND, &cmd);
> > + if (cmd & PCI_COMMAND_MEMORY)
> > + return -EBUSY;
> > +
> > + return 0;
> > +}
> > +
> > 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); @@ -444,9 +463,9 @@ 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)
> > - return -EBUSY;
> > + ret = pci_memory_decoding(dev, resno);
> > + if (ret)
> > + return ret;
> >
> > sizes = pci_rebar_get_possible_sizes(dev, resno);
> > if (!sizes)
> > @@ -463,19 +482,31 @@ 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;
> > +#ifdef CONFIG_PCI_IOV
> > + if (resno >= PCI_IOV_RESOURCES)
> > + dev->sriov->barsz[resno - PCI_IOV_RESOURCES] = pci_rebar_size_to_bytes(size);
> > + else
> > +#endif
> > + res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
> >
> > /* Check if the new config works by trying to assign everything. */
> > if (dev->bus->self) {
> > ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
> > - if (ret)
> > + if (ret && ret != -ENOENT)
> > goto error_resize;
> > }
> > return 0;
> >
> > error_resize:
> > pci_rebar_set_size(dev, resno, old);
> > - res->end = res->start + pci_rebar_size_to_bytes(old) - 1;
> > +
> > +#ifdef CONFIG_PCI_IOV
> > + if (resno >= PCI_IOV_RESOURCES)
> > + dev->sriov->barsz[resno - PCI_IOV_RESOURCES] = pci_rebar_size_to_bytes(old);
> > + else
> > +#endif
> > + res->end = res->start + pci_rebar_size_to_bytes(old) - 1;
> > +
> > return ret;
> > }
> > EXPORT_SYMBOL(pci_resize_resource);
> > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index a39193213..a66b90982 100644
> > --- a/include/uapi/linux/pci_regs.h
> > +++ b/include/uapi/linux/pci_regs.h
> > @@ -738,6 +738,7 @@
> > #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_PL_32GT 0x2A /* Physical Layer 32.0 GT/s */
> > --
> > 2.34.1
> >
>