Messages in this thread | | | Date | Fri, 17 Dec 2021 11:58:58 +0100 | Subject | Re: [PATCH 1/2] PCI: Add support for VF Resizable Bar extended cap | From | Michał Winiarski <> |
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On 16.12.2021 08:50, Christian König wrote: > > > Am 15.12.21 um 15:16 schrieb Michał Winiarski: >> 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@intel.com> >> --- >> drivers/pci/pci.c | 25 +++++++++++++++-- >> drivers/pci/setup-res.c | 53 ++++++++++++++++++++++++++++++++--- >> include/uapi/linux/pci_regs.h | 1 + >> 3 files changed, 72 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 3d2fb394986a4..89448c5104e46 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -1682,12 +1682,15 @@ static void pci_restore_config_space(struct >> pci_dev *pdev) >> } >> } >> -static void pci_restore_rebar_state(struct pci_dev *pdev) >> +static void __pci_restore_rebar_state(struct pci_dev *pdev, int cap) >> { >> unsigned int pos, nbars, i; >> u32 ctrl; >> - pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_REBAR); >> + if (WARN_ON(cap != PCI_EXT_CAP_ID_REBAR && cap != >> PCI_EXT_CAP_ID_VF_REBAR)) >> + return; >> + >> + pos = pci_find_ext_capability(pdev, cap); >> if (!pos) >> return; >> @@ -1709,6 +1712,14 @@ static void pci_restore_rebar_state(struct >> pci_dev *pdev) >> } >> } >> +static void pci_restore_rebar_state(struct pci_dev *pdev) >> +{ >> + __pci_restore_rebar_state(pdev, PCI_EXT_CAP_ID_REBAR); >> +#ifdef CONFIG_PCI_IOV >> + __pci_restore_rebar_state(pdev, PCI_EXT_CAP_ID_VF_REBAR); >> +#endif >> +} >> + > > It's probably cleaner to let the caller specify the capability to > restore directly.
Ok - I'll go with: pci_restore_rebar_state(dev); pci_restore_vf_rebar_state(dev);
in pci_restore_state() (where pci_restore_vf_rebar_state() will be "no-op" if there's no CONFIG_PCI_IOV).
> >> /** >> * pci_restore_state - Restore the saved state of a PCI device >> * @dev: PCI device that we're dealing with >> @@ -3639,10 +3650,18 @@ 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 7f1acb3918d0c..1946e52e7678a 100644 >> --- a/drivers/pci/setup-res.c >> +++ b/drivers/pci/setup-res.c >> @@ -407,13 +407,36 @@ void pci_release_resource(struct pci_dev *dev, >> int resno) >> } >> EXPORT_SYMBOL(pci_release_resource); >> +static int pci_memory_decoding(struct pci_dev *dev) >> +{ >> + u16 cmd; >> + >> + pci_read_config_word(dev, PCI_COMMAND, &cmd); >> + if (cmd & PCI_COMMAND_MEMORY) >> + return -EBUSY; >> + >> + return 0; >> +} >> + >> +#ifdef CONFIG_PCI_IOV >> +static int pci_vf_memory_decoding(struct pci_dev *dev) >> +{ >> + u16 cmd; >> + >> + pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_CTRL, &cmd); >> + if (cmd & PCI_SRIOV_CTRL_MSE) >> + return -EBUSY; >> + >> + return 0; >> +} >> +#endif >> + >> 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); >> @@ -424,9 +447,14 @@ 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; >> +#ifdef CONFIG_PCI_IOV >> + if (resno >= PCI_IOV_RESOURCES) >> + ret = pci_vf_memory_decoding(dev); >> + else >> +#endif >> + ret = pci_memory_decoding(dev); >> + if (ret) >> + return ret; > > Way to many #ifdef spread around inside the code, please restructure that. > > For example concentrating the logic in a single function should help: > > static int pci_check_decoding_disabled(..., inr resno) > { > > #ifdef CONFIG_PCI_IOV > if (resno... > return -EBUSY; > else > return 0; > #endif > > if (...) > return -EBUSY; > return 0; > > } >
Ok.
>> sizes = pci_rebar_get_possible_sizes(dev, resno); >> if (!sizes) >> @@ -445,6 +473,14 @@ int pci_resize_resource(struct pci_dev *dev, int >> resno, int size) >> 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); >> + res->end = res->start + >> + resource_size(res) * pci_sriov_get_totalvfs(dev) - 1; >> + } >> +#endif >> + >> /* 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); >> @@ -456,6 +492,15 @@ 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; >> + >> +#ifdef CONFIG_PCI_IOV >> + if (resno >= PCI_IOV_RESOURCES) { >> + dev->sriov->barsz[resno - PCI_IOV_RESOURCES] = >> pci_rebar_size_to_bytes(old); >> + res->end = res->start + >> + pci_rebar_size_to_bytes(old) * >> pci_sriov_get_totalvfs(dev) - 1; >> + } >> +#endif >> + > > Looks like this deserves it's own function.
I'll extract the whole "restore after failed resize" to separate function (for both native and IOV).
Thanks! -Michał
> > Regards, > Christian. > >> return ret; >> } >> EXPORT_SYMBOL(pci_resize_resource); >> diff --git a/include/uapi/linux/pci_regs.h >> b/include/uapi/linux/pci_regs.h >> index ff6ccbc6efe96..7f5726d23b038 100644 >> --- a/include/uapi/linux/pci_regs.h >> +++ b/include/uapi/linux/pci_regs.h >> @@ -734,6 +734,7 @@ >> #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_MAX PCI_EXT_CAP_ID_PL_16GT >
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