[PATCH kernel 4/5] powerpc/powernv/npu: Factor out OPAL calls from context manipulation
Alexey Kardashevskiy
aik at ozlabs.ru
Tue Nov 13 17:13:01 AEDT 2018
On 08/11/2018 16:05, David Gibson wrote:
> On Mon, Oct 15, 2018 at 08:33:00PM +1100, Alexey Kardashevskiy wrote:
>> At the moment the NPU context init/destroy code calls OPAL. The init
>> handler in OPAL configures the NPU to pass ATS requests to nested MMU,
>> the destroy handler does nothing besides sanity checks.
>>
>> Since the init handler programs the NPU with a wildcard for LPID/PID,
>> this can be done at the point where a GPU is mapped to an LPAR; it also
>> makes calling opal_npu_destroy_context() unnecessary in this context
>> (this will change with VFIO later though).
>
> I think this wants a bit more explanation. It certainly makes me
> nervous removing the destroy_context calls with nothing replacing
> them.
>
>> Also, the pnv_npu2_init() helper does not really need to call OPAL as
>> well as it inialized an NPU structure and does not interact with GPU or
>> NPU at that moment.
>>
>> This moves OPAL calls to a separate helper. With this change, the API
>> for GPUs does not do any OPAL calls and therefore can be used by both
>> pseries and powernv platforms. The new pnv_npu2_map_lpar_phb() helper
>> should be called on powernv only as it does OPAL calls and it takes
>> an MSR mask which NPU adds to ATS requests so nested MMU knows what
>> translations are permitted; the VFIO/KVM will not set MSR_HV.
>>
>> This removes the check for FW_FEATURE_OPAL as pnv_npu2_init_context/
>> pnv_npu2_release_context/pnv_npu2_init do not call OPAL anymore.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
>> ---
>> arch/powerpc/include/asm/pci.h | 1 +
>> arch/powerpc/platforms/powernv/pci.h | 2 +-
>> arch/powerpc/platforms/powernv/npu-dma.c | 100 +++++++++++++++---------------
>> arch/powerpc/platforms/powernv/pci-ioda.c | 7 ++-
>> 4 files changed, 57 insertions(+), 53 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
>> index 1a96075..f196df6 100644
>> --- a/arch/powerpc/include/asm/pci.h
>> +++ b/arch/powerpc/include/asm/pci.h
>> @@ -130,5 +130,6 @@ extern void pcibios_scan_phb(struct pci_controller *hose);
>> extern struct pci_dev *pnv_pci_get_gpu_dev(struct pci_dev *npdev);
>> extern struct pci_dev *pnv_pci_get_npu_dev(struct pci_dev *gpdev, int index);
>> extern void pnv_npu2_devices_init(void);
>> +extern int pnv_npu2_init(struct pci_controller *hose);
>>
>> #endif /* __ASM_POWERPC_PCI_H */
>> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>> index 3b7617d..ca2ce4b 100644
>> --- a/arch/powerpc/platforms/powernv/pci.h
>> +++ b/arch/powerpc/platforms/powernv/pci.h
>> @@ -224,7 +224,7 @@ extern long pnv_npu_set_window(struct pnv_ioda_pe *npe, int num,
>> extern long pnv_npu_unset_window(struct pnv_ioda_pe *npe, int num);
>> extern void pnv_npu_take_ownership(struct pnv_ioda_pe *npe);
>> extern void pnv_npu_release_ownership(struct pnv_ioda_pe *npe);
>> -extern int pnv_npu2_init(struct pnv_phb *phb);
>> +extern void pnv_npu2_map_lpar_phb(struct pnv_phb *nphb, unsigned long msr);
>>
>> /* pci-ioda-tce.c */
>> #define POWERNV_IOMMU_DEFAULT_LEVELS 1
>> diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
>> index cb2b4f9..677f30a 100644
>> --- a/arch/powerpc/platforms/powernv/npu-dma.c
>> +++ b/arch/powerpc/platforms/powernv/npu-dma.c
>> @@ -762,7 +762,6 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>> u32 nvlink_index;
>> struct device_node *nvlink_dn;
>> struct mm_struct *mm = current->mm;
>> - struct pnv_phb *nphb;
>> struct npu *npu;
>> struct npu_context *npu_context;
>>
>> @@ -772,9 +771,6 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>> */
>> struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
>>
>> - if (!firmware_has_feature(FW_FEATURE_OPAL))
>> - return ERR_PTR(-ENODEV);
>> -
>> if (!npdev)
>> /* No nvlink associated with this GPU device */
>> return ERR_PTR(-ENODEV);
>> @@ -792,22 +788,9 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>> return ERR_PTR(-EINVAL);
>> }
>>
>> - nphb = pci_bus_to_host(npdev->bus)->private_data;
>> npu = npdev_to_npu(npdev);
>>
>> /*
>> - * Setup the NPU context table for a particular GPU. These need to be
>> - * per-GPU as we need the tables to filter ATSDs when there are no
>> - * active contexts on a particular GPU. It is safe for these to be
>> - * called concurrently with destroy as the OPAL call takes appropriate
>> - * locks and refcounts on init/destroy.
>> - */
>> - rc = opal_npu_init_context(nphb->opal_id, mm->context.id,
>> flags,
>
> AFAICT this was the only use of 'flags' in this function, so it should
> be removed from the signature, no?
It should, however this is ABI and the vendor driver is calling this
function with the flags so I cannot just ditch the flags.
>
>> - PCI_DEVID(gpdev->bus->number, gpdev->devfn));
>> - if (rc < 0)
>> - return ERR_PTR(-ENOSPC);
>> -
>> - /*
>> * We store the npu pci device so we can more easily get at the
>> * associated npus.
>> */
>> @@ -817,9 +800,6 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>> if (npu_context->release_cb != cb ||
>> npu_context->priv != priv) {
>> spin_unlock(&npu2_devices.context_lock);
>> - opal_npu_destroy_context(nphb->opal_id, mm->context.id,
>> - PCI_DEVID(gpdev->bus->number,
>> - gpdev->devfn));
>> return ERR_PTR(-EINVAL);
>> }
>>
>> @@ -845,9 +825,6 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
>>
>> if (rc) {
>> kfree(npu_context);
>> - opal_npu_destroy_context(nphb->opal_id, mm->context.id,
>> - PCI_DEVID(gpdev->bus->number,
>> - gpdev->devfn));
>> return ERR_PTR(rc);
>> }
>>
>> @@ -900,7 +877,6 @@ void pnv_npu2_destroy_context(struct npu_context *npu_context,
>> struct pci_dev *gpdev)
>> {
>> int removed;
>> - struct pnv_phb *nphb;
>> struct npu *npu;
>> struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
>> struct device_node *nvlink_dn;
>> @@ -909,18 +885,12 @@ void pnv_npu2_destroy_context(struct npu_context *npu_context,
>> if (WARN_ON(!npdev))
>> return;
>>
>> - if (!firmware_has_feature(FW_FEATURE_OPAL))
>> - return;
>> -
>> - nphb = pci_bus_to_host(npdev->bus)->private_data;
>> npu = npdev_to_npu(npdev);
>> nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
>> if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
>> &nvlink_index)))
>> return;
>> WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], NULL);
>> - opal_npu_destroy_context(nphb->opal_id, npu_context->mm->context.id,
>> - PCI_DEVID(gpdev->bus->number, gpdev->devfn));
>> spin_lock(&npu2_devices.context_lock);
>> removed = kref_put(&npu_context->kref, pnv_npu2_release_context);
>> spin_unlock(&npu2_devices.context_lock);
>> @@ -952,9 +922,6 @@ int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
>> /* mmap_sem should be held so the struct_mm must be present */
>> struct mm_struct *mm = context->mm;
>>
>> - if (!firmware_has_feature(FW_FEATURE_OPAL))
>> - return -ENODEV;
>> -
>> WARN_ON(!rwsem_is_locked(&mm->mmap_sem));
>>
>> for (i = 0; i < count; i++) {
>> @@ -983,15 +950,11 @@ int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,
>> }
>> EXPORT_SYMBOL(pnv_npu2_handle_fault);
>>
>> -int pnv_npu2_init(struct pnv_phb *phb)
>> +int pnv_npu2_init(struct pci_controller *hose)
>> {
>> unsigned int i;
>> u64 mmio_atsd;
>> - struct device_node *dn;
>> - struct pci_dev *gpdev;
>> static int npu_index;
>> - uint64_t rc = 0;
>> - struct pci_controller *hose = phb->hose;
>> struct npu *npu;
>> int ret;
>>
>> @@ -1006,18 +969,6 @@ int pnv_npu2_init(struct pnv_phb *phb)
>> }
>>
>> npu->nmmu_flush = of_property_read_bool(hose->dn, "ibm,nmmu-flush");
>> - for_each_child_of_node(phb->hose->dn, dn) {
>> - gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
>> - if (gpdev) {
>> - rc = opal_npu_map_lpar(phb->opal_id,
>> - PCI_DEVID(gpdev->bus->number, gpdev->devfn),
>> - 0, 0);
>> - if (rc)
>> - dev_err(&gpdev->dev,
>> - "Error %lld mapping device to LPAR\n",
>> - rc);
>> - }
>> - }
>>
>> for (i = 0; !of_property_read_u64_index(hose->dn, "ibm,mmio-atsd",
>> i, &mmio_atsd); i++)
>> @@ -1047,3 +998,52 @@ int pnv_npu2_init(struct pnv_phb *phb)
>>
>> return ret;
>> }
>> +
>> +void pnv_npu2_map_lpar_phb(struct pnv_phb *nphb, unsigned long msr)
>> +{
>> + struct pci_dev *gpdev;
>> + struct device_node *dn;
>> + int ret;
>> + struct pci_controller *hose = nphb->hose;
>> +
>> + for_each_child_of_node(hose->dn, dn) {
>> + gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
>> + if (!gpdev)
>> + continue;
>> +
>> + dev_dbg(&gpdev->dev, "Map LPAR opalid=%llu\n", nphb->opal_id);
>> + ret = opal_npu_map_lpar(nphb->opal_id,
>> + PCI_DEVID(gpdev->bus->number, gpdev->devfn),
>> + 0, 0);
>> + if (!ret)
>> + continue;
>> + dev_err(&gpdev->dev, "Error %d mapping device to LPAR\n", ret);
>> + }
>> +
>> + /*
>> + * It seems that touching NPU2_XTS_BDF_MAP in the way
>> + * the opal_npu_map_lpar() does somehow affects the result of
>> + * what opal_npu_init_context() does so let's put the latter in
>> + * a separate loop.
>> + */
>> + for_each_child_of_node(hose->dn, dn) {
>> + gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
>> + if (!gpdev)
>> + continue;
>> +
>> + /*
>> + * Setup the NPU context table for a particular GPU. These need
>> + * to be per-GPU as we need the tables to filter ATSDs when
>> + * there are no active contexts on a particular GPU. It is safe
>> + * for these to be called concurrently with destroy as the OPAL
>> + * call takes appropriate locks and refcounts on init/destroy.
>> + */
>> + dev_dbg(&gpdev->dev, "init context opalid=%llu\n",
>> + nphb->opal_id);
>> + ret = opal_npu_init_context(nphb->opal_id, 0/*__unused*/, msr,
>> + PCI_DEVID(gpdev->bus->number, gpdev->devfn));
>> + if (!ret)
>> + continue;
>> + dev_err(&gpdev->dev, "Failed to init context: %d\n", ret);
>> + }
>> +}
>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>> index 0cc81c0..56a1398 100644
>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>> @@ -1287,8 +1287,11 @@ static void pnv_pci_ioda_setup_PEs(void)
>> /* PE#0 is needed for error reporting */
>> pnv_ioda_reserve_pe(phb, 0);
>> pnv_ioda_setup_npu_PEs(hose->bus);
>> - if (phb->model == PNV_PHB_MODEL_NPU2)
>> - pnv_npu2_init(phb);
>> + if (phb->model == PNV_PHB_MODEL_NPU2) {
>> + pnv_npu2_init(hose);
>> + pnv_npu2_map_lpar_phb(phb,
>> + MSR_DR | MSR_PR | MSR_HV);
>
> This is the only caller of pnv_np2_map_lpar_phb(), do we need the
> second parameter? I take it those "flags" to the function are
> actually an MSR value; that wasn't clear from the previous code.
Correct, the flags are some MSR bits, the name was there before I
started touching this... The flags are (MSR_DR | MSR_PR) when VFIO
subdriver calls pnv_npu2_map_lpar_phb from later patches. I'll repost
the whole thing as a single patchset, splitting it in parts was a bad
idea. Thanks,
>
>> + }
>> }
>> if (phb->type == PNV_PHB_NPU_OCAPI) {
>> bus = hose->bus;
>
--
Alexey
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