kernel.git/arch/powerpc/platforms/pseries/setup.c, branch linux-6.7.y

powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT

2023-08-24T12:33:17Z

lppaca_shared_proc() takes a pointer to the lppaca which is typically accessed through get_lppaca(). With DEBUG_PREEMPT enabled, this leads to checking if preemption is enabled, for example: BUG: using smp_processor_id() in preemptible [00000000] code: grep/10693 caller is lparcfg_data+0x408/0x19a0 CPU: 4 PID: 10693 Comm: grep Not tainted 6.5.0-rc3 #2 Call Trace: dump_stack_lvl+0x154/0x200 (unreliable) check_preemption_disabled+0x214/0x220 lparcfg_data+0x408/0x19a0 ... This isn't actually a problem however, as it does not matter which lppaca is accessed, the shared proc state will be the same. vcpudispatch_stats_procfs_init() already works around this by disabling preemption, but the lparcfg code does not, erroring any time /proc/powerpc/lparcfg is accessed with DEBUG_PREEMPT enabled. Instead of disabling preemption on the caller side, rework lppaca_shared_proc() to not take a pointer and instead directly access the lppaca, bypassing any potential preemption checks. Fixes: f13c13a00512 ("powerpc: Stop using non-architected shared_proc field in lppaca") Signed-off-by: Russell Currey [mpe: Rework to avoid needing a definition in paca.h and lppaca.h] Signed-off-by: Michael Ellerman Link: https://msgid.link/20230823055317.751786-4-mpe@ellerman.id.au

powerpc/mm: Cleanup memory block size probing

2023-08-18T07:03:15Z

Parse the device tree in early init to find the memory block size to be used by the kernel. Consolidate the memory block size device tree parsing to one helper and use that on both powernv and pseries. We still want to use machine-specific callback because on all machine types other than powernv and pseries we continue to return MIN_MEMORY_BLOCK_SIZE. pseries_memory_block_size used to look for the second memory block (memory@x) to determine the memory_block_size value. This patch changed that to look at all memory blocks and make sure we can map them all correctly using the computed memory block size value. Add workaround to force 256MB memory block size if device driver managed memory such as GPU memory is present. This helps to add GPU memory that is not aligned to 1G. Co-developed-by: Reza Arbab Signed-off-by: Reza Arbab Signed-off-by: "Aneesh Kumar K.V" Signed-off-by: Michael Ellerman Link: https://msgid.link/20230801044447.11275-1-aneesh.kumar@linux.ibm.com

powerpc/pseries: Initialise CPU hotplug callbacks earlier

2023-08-02T12:43:42Z

As part of the generic HOTPLUG_SMT code, there is support for disabling secondary SMT threads at boot time, by passing "nosmt" on the kernel command line. The way that is implemented is the secondary threads are brought partly online, and then taken back offline again. That is done to support x86 CPUs needing certain initialisation done on all threads. However powerpc has similar needs, see commit d70a54e2d085 ("powerpc/powernv: Ignore smt-enabled on Power8 and later"). For that to work the powerpc CPU hotplug callbacks need to be registered before secondary CPUs are brought online, otherwise __cpu_disable() fails due to smp_ops->cpu_disable being NULL. So split the basic initialisation into pseries_cpu_hotplug_init() which can be called early from setup_arch(). The DLPAR related initialisation can still be done later, because it needs to do allocations. Signed-off-by: Michael Ellerman Link: https://msgid.link/20230705145143.40545-9-ldufour@linux.ibm.com

powerpc: Make generic_calibrate_decr() the default

2023-03-15T21:56:48Z

ppc_md.calibrate_decr() is a mandatory item. Its nullity is never checked so it must be non null on all platforms. Most platforms define generic_calibrate_decr() as their ppc_md.calibrate_decr(). Have time_init() call generic_calibrate_decr() when ppc_md.calibrate_decr() is NULL, and remove default assignment from all machines. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/6cb9865d916231c38401ba34ad1a98c249fae135.1676711562.git.christophe.leroy@csgroup.eu

powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains

2023-03-14T13:51:46Z

Up until now PPC64 managed to avoid using iommu_ops. The VFIO driver uses a SPAPR TCE sub-driver and all iommu_ops uses were kept in the Type1 VFIO driver. Recent development added 2 uses of iommu_ops to the generic VFIO which broke POWER: - a coherency capability check; - blocking IOMMU domain - iommu_group_dma_owner_claimed()/... This adds a simple iommu_ops which reports support for cache coherency and provides a basic support for blocking domains. No other domain types are implemented so the default domain is NULL. Since now iommu_ops controls the group ownership, this takes it out of VFIO. This adds an IOMMU device into a pci_controller (=PHB) and registers it in the IOMMU subsystem, iommu_ops is registered at this point. This setup is done in postcore_initcall_sync. This replaces iommu_group_add_device() with iommu_probe_device() as the former misses necessary steps in connecting PCI devices to IOMMU devices. This adds a comment about why explicit iommu_probe_device() is still needed. The previous discussion is here: https://lore.kernel.org/r/20220707135552.3688927-1-aik@ozlabs.ru/ https://lore.kernel.org/r/20220701061751.1955857-1-aik@ozlabs.ru/ Fixes: e8ae0e140c05 ("vfio: Require that devices support DMA cache coherence") Fixes: 70693f470848 ("vfio: Set DMA ownership for VFIO devices") Signed-off-by: Alexey Kardashevskiy Signed-off-by: Timothy Pearson Acked-by: Alex Williamson [mpe: Fix CONFIG_IOMMU_API=n build] Signed-off-by: Michael Ellerman Link: https://msgid.link/2000135730.16998523.1678123860135.JavaMail.zimbra@raptorengineeringinc.com

powerpc/rtas: arch-wide function token lookup conversions

2023-02-13T11:35:03Z

With the tokens for all implemented RTAS functions now available via rtas_function_token(), which is optimal and safe for arbitrary contexts, there is no need to use rtas_token() or cache its result. Most conversions are trivial, but a few are worth describing in more detail: * Error injection token comparisons for lockdown purposes are consolidated into a simple predicate: token_is_restricted_errinjct(). * A couple of special cases in block_rtas_call() do not use rtas_token() but perform string comparisons against names in the function table. These are converted to compare against token values instead, which is logically equivalent but less expensive. * The lookup for the ibm,os-term token can be deferred until needed, instead of caching it at boot to avoid device tree traversal during panic. * Since rtas_function_token() accesses a read-only data structure without taking any locks, xmon's lookup of set-indicator can be performed as needed instead of cached at startup. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-20-26929c8cce78@linux.ibm.com

powerpc/pseries: convert CMO probe to papr_sysparm API

2023-02-13T11:35:03Z

Convert the direct invocation of the ibm,get-system-parameter RTAS function to papr_sysparm_get(). Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-15-26929c8cce78@linux.ibm.com

powerpc/pseries/setup: add missing RTAS retry status handling

2023-02-13T11:35:01Z

The ibm,get-system-parameter RTAS function may return -2 or 990x, which indicate that the caller should try again. pSeries_cmo_feature_init() ignores this, making it possible to fail to detect cooperative memory overcommit capabilities during boot. Move the RTAS call into a conventional rtas_busy_delay()-based loop, dropping unnecessary clearing of rtas_data_buf. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-5-26929c8cce78@linux.ibm.com

powerpc/pseries: Add firmware details to the hardware description

2022-09-30T08:35:53Z

Add firmware version details to the hardware description, which is printed at boot and in case of an oops. Use /hypervisor if we find it, though currently it only exists if we're running under qemu. Look for "ibm,powervm-partition" which is specified in PAPR+ v2.11 and tells us we're running under PowerVM. Failing that look for "ibm,fw-net-version" which is seen on PowerVM going back to at least Power6. eg: Hardware name: ... of:IBM,FW860.42 (SV860_138) hv:phyp Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220930082709.55830-6-mpe@ellerman.id.au

powerpc/pseries: Implement CONFIG_PARAVIRT_TIME_ACCOUNTING

2022-09-05T04:14:02Z

CONFIG_VIRT_CPU_ACCOUNTING_GEN under pseries does not provide stolen time accounting unless CONFIG_PARAVIRT_TIME_ACCOUNTING is enabled. Implement this using the VPA accumulated wait counters. Note this will not work on current KVM hosts because KVM does not implement the VPA dispatch counters (yet). It could be implemented with the dispatch trace log as it is for VIRT_CPU_ACCOUNTING_NATIVE, but that is not necessary for the more limited accounting provided by PARAVIRT_TIME_ACCOUNTING, and it is more expensive, complex, and has downsides like potential log wrap. From Shrikanth: [...] it was tested on Power10 [PowerVM] Shared LPAR. system has two LPAR. we will call first one LPAR1 and second one as LPAR2. Test was carried out in SMT=1. Similar observation was seen in SMT=8 as well. LPAR config header from each LPAR is below. LPAR1 is twice as big as LPAR2. Since Both are sharing the same underlying hardware, work stealing will happen when both the LPAR's are contending for the same resource. LPAR1: type=Shared mode=Uncapped smt=Off lcpu=40 cpus=40 ent=20.00 LPAR2: type=Shared mode=Uncapped smt=Off lcpu=20 cpus=40 ent=10.00 mpstat was used to check for the utilization. stress-ng has been used as the workload. Few cases are tested. when the both LPAR are idle there is no steal time. when LPAR1 starts running at 100% which consumes all of the physical resource, steal time starts to get accounted. With LPAR1 running at 100% and LPAR2 starts running, steal time starts increasing. This is as expected. When the LPAR2 Load is increased further, steal time increases further. Case 1: 0% LPAR1; 0% LPAR2 %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.00 99.95 Case 2: 100% LPAR1; 0% LPAR2 %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 97.68 0.00 0.00 0.00 0.00 0.00 2.32 0.00 0.00 0.00 Case 3: 100% LPAR1; 50% LPAR2 %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 86.34 0.00 0.10 0.00 0.00 0.03 13.54 0.00 0.00 0.00 Case 4: 100% LPAR1; 100% LPAR2 %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 78.54 0.00 0.07 0.00 0.00 0.02 21.36 0.00 0.00 0.00 Case 5: 50% LPAR1; 100% LPAR2 %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 49.37 0.00 0.00 0.00 0.00 0.00 1.17 0.00 0.00 49.47 Patch is accounting for the steal time and basic tests are holding good. Signed-off-by: Nicholas Piggin Tested-by: Shrikanth Hegde [mpe: Add SPDX tag to new paravirt_api_clock.h] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220902085316.2071519-3-npiggin@gmail.com