| Message ID | 20150902011123.GA47557@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 09/02/2015 11:11 AM, Nishanth Aravamudan wrote: > When attempting to kdump with the 4.2 kernel, we see for each PCI > device: > > pci 0003:01 : [PE# 000] Assign DMA32 space > pci 0003:01 : [PE# 000] Setting up 32-bit TCE table at 0..80000000 > pci 0003:01 : [PE# 000] Failed to create 32-bit TCE table, err -22 > PCI: Domain 0004 has 8 available 32-bit DMA segments > PCI: 4 PE# for a total weight of 70 > pci 0004:01 : [PE# 002] Assign DMA32 space > pci 0004:01 : [PE# 002] Setting up 32-bit TCE table at 0..80000000 > pci 0004:01 : [PE# 002] Failed to create 32-bit TCE table, err -22 > pci 0004:0d : [PE# 005] Assign DMA32 space > pci 0004:0d : [PE# 005] Setting up 32-bit TCE table at 0..80000000 > pci 0004:0d : [PE# 005] Failed to create 32-bit TCE table, err -22 > pci 0004:0e : [PE# 006] Assign DMA32 space > pci 0004:0e : [PE# 006] Setting up 32-bit TCE table at 0..80000000 > pci 0004:0e : [PE# 006] Failed to create 32-bit TCE table, err -22 > pci 0004:10 : [PE# 008] Assign DMA32 space > pci 0004:10 : [PE# 008] Setting up 32-bit TCE table at 0..80000000 > pci 0004:10 : [PE# 008] Failed to create 32-bit TCE table, err -22 > > and eventually the kdump kernel fails to boot as none of the PCI devices > (including the disk controller) are successfully initialized. > > The EINVAL response is because the DMA window (the 2GB base window) is > larger than the kdump kernel's reserved memory (crashkernel=, in this > case specified to be 1024M). The check in question, > > if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size)) > > is a valid sanity check for pnv_pci_ioda2_table_alloc_pages(), so adjust > the caller to pass in a smaller window size if our maximum memory value > is smaller than the DMA window. > > After this change, the PCI devices successfully set up the 32-bit TCE > table and kdump succeeds. > > The problem was seen on a Firestone machine originally. > > Fixes: aca6913f5551 ("powerpc/powernv/ioda2: Introduce helpers to allocate TCE pages") > Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com> > > diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c > index 85cbc96eff6c..0d7967e31169 100644 > --- a/arch/powerpc/platforms/powernv/pci-ioda.c > +++ b/arch/powerpc/platforms/powernv/pci-ioda.c > @@ -2077,10 +2077,17 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe) > { > struct iommu_table *tbl = NULL; > long rc; > + /* > + * In memory constrained environments, e.g. kdump kernel, the > + * DMA window can be larger than available memory, which will > + * cause errors later. > + */ > + __u64 window_size = I asked for "const __u64" ;) Anyway, Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> > + min((u64)pe->table_group.tce32_size, memory_hotplug_max()); > > rc = pnv_pci_ioda2_create_table(&pe->table_group, 0, > IOMMU_PAGE_SHIFT_4K, > - pe->table_group.tce32_size, > + window_size, > POWERNV_IOMMU_DEFAULT_LEVELS, &tbl); > if (rc) { > pe_err(pe, "Failed to create 32-bit TCE table, err %ld", >
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 85cbc96eff6c..0d7967e31169 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2077,10 +2077,17 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe) { struct iommu_table *tbl = NULL; long rc; + /* + * In memory constrained environments, e.g. kdump kernel, the + * DMA window can be larger than available memory, which will + * cause errors later. + */ + __u64 window_size = + min((u64)pe->table_group.tce32_size, memory_hotplug_max()); rc = pnv_pci_ioda2_create_table(&pe->table_group, 0, IOMMU_PAGE_SHIFT_4K, - pe->table_group.tce32_size, + window_size, POWERNV_IOMMU_DEFAULT_LEVELS, &tbl); if (rc) { pe_err(pe, "Failed to create 32-bit TCE table, err %ld",
When attempting to kdump with the 4.2 kernel, we see for each PCI device: pci 0003:01 : [PE# 000] Assign DMA32 space pci 0003:01 : [PE# 000] Setting up 32-bit TCE table at 0..80000000 pci 0003:01 : [PE# 000] Failed to create 32-bit TCE table, err -22 PCI: Domain 0004 has 8 available 32-bit DMA segments PCI: 4 PE# for a total weight of 70 pci 0004:01 : [PE# 002] Assign DMA32 space pci 0004:01 : [PE# 002] Setting up 32-bit TCE table at 0..80000000 pci 0004:01 : [PE# 002] Failed to create 32-bit TCE table, err -22 pci 0004:0d : [PE# 005] Assign DMA32 space pci 0004:0d : [PE# 005] Setting up 32-bit TCE table at 0..80000000 pci 0004:0d : [PE# 005] Failed to create 32-bit TCE table, err -22 pci 0004:0e : [PE# 006] Assign DMA32 space pci 0004:0e : [PE# 006] Setting up 32-bit TCE table at 0..80000000 pci 0004:0e : [PE# 006] Failed to create 32-bit TCE table, err -22 pci 0004:10 : [PE# 008] Assign DMA32 space pci 0004:10 : [PE# 008] Setting up 32-bit TCE table at 0..80000000 pci 0004:10 : [PE# 008] Failed to create 32-bit TCE table, err -22 and eventually the kdump kernel fails to boot as none of the PCI devices (including the disk controller) are successfully initialized. The EINVAL response is because the DMA window (the 2GB base window) is larger than the kdump kernel's reserved memory (crashkernel=, in this case specified to be 1024M). The check in question, if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size)) is a valid sanity check for pnv_pci_ioda2_table_alloc_pages(), so adjust the caller to pass in a smaller window size if our maximum memory value is smaller than the DMA window. After this change, the PCI devices successfully set up the 32-bit TCE table and kdump succeeds. The problem was seen on a Firestone machine originally. Fixes: aca6913f5551 ("powerpc/powernv/ioda2: Introduce helpers to allocate TCE pages") Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>