<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel.git/arch/powerpc/platforms/pseries, branch linux-6.7.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.
</subtitle>
<id>https://git.0xinfinity.dev/distro/kernel.git/atom?h=linux-6.7.y</id>
<link rel='self' href='https://git.0xinfinity.dev/distro/kernel.git/atom?h=linux-6.7.y'/>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/'/>
<updated>2024-03-26T22:18:41Z</updated>
<entry>
<title>powerpc/pseries: Fix potential memleak in papr_get_attr()</title>
<updated>2024-03-26T22:18:41Z</updated>
<author>
<name>Qiheng Lin</name>
</author>
<published>2022-12-08T13:34:49Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=7f7d39fe3d80d6143404940b2413010cf6527029'/>
<id>urn:sha1:7f7d39fe3d80d6143404940b2413010cf6527029</id>
<content type='text'>
[ Upstream commit cda9c0d556283e2d4adaa9960b2dc19b16156bae ]

`buf` is allocated in papr_get_attr(), and krealloc() of `buf`
could fail. We need to free the original `buf` in the case of failure.

Fixes: 3c14b73454cf ("powerpc/pseries: Interface to represent PAPR firmware attributes")
Signed-off-by: Qiheng Lin &lt;linqiheng@huawei.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20221208133449.16284-1-linqiheng@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries/iommu: IOMMU table is not initialized for kdump over SR-IOV</title>
<updated>2024-03-06T14:54:00Z</updated>
<author>
<name>Gaurav Batra</name>
</author>
<published>2024-01-25T20:30:17Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=5da6d306f315344af1ca2eff4bd9b10b130f0c28'/>
<id>urn:sha1:5da6d306f315344af1ca2eff4bd9b10b130f0c28</id>
<content type='text'>
[ Upstream commit 09a3c1e46142199adcee372a420b024b4fc61051 ]

When kdump kernel tries to copy dump data over SR-IOV, LPAR panics due
to NULL pointer exception:

  Kernel attempted to read user page (0) - exploit attempt? (uid: 0)
  BUG: Kernel NULL pointer dereference on read at 0x00000000
  Faulting instruction address: 0xc000000020847ad4
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: mlx5_core(+) vmx_crypto pseries_wdt papr_scm libnvdimm mlxfw tls psample sunrpc fuse overlay squashfs loop
  CPU: 12 PID: 315 Comm: systemd-udevd Not tainted 6.4.0-Test102+ #12
  Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries
  NIP:  c000000020847ad4 LR: c00000002083b2dc CTR: 00000000006cd18c
  REGS: c000000029162ca0 TRAP: 0300   Not tainted  (6.4.0-Test102+)
  MSR:  800000000280b033 &lt;SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE&gt;  CR: 48288244  XER: 00000008
  CFAR: c00000002083b2d8 DAR: 0000000000000000 DSISR: 40000000 IRQMASK: 1
  ...
  NIP _find_next_zero_bit+0x24/0x110
  LR  bitmap_find_next_zero_area_off+0x5c/0xe0
  Call Trace:
    dev_printk_emit+0x38/0x48 (unreliable)
    iommu_area_alloc+0xc4/0x180
    iommu_range_alloc+0x1e8/0x580
    iommu_alloc+0x60/0x130
    iommu_alloc_coherent+0x158/0x2b0
    dma_iommu_alloc_coherent+0x3c/0x50
    dma_alloc_attrs+0x170/0x1f0
    mlx5_cmd_init+0xc0/0x760 [mlx5_core]
    mlx5_function_setup+0xf0/0x510 [mlx5_core]
    mlx5_init_one+0x84/0x210 [mlx5_core]
    probe_one+0x118/0x2c0 [mlx5_core]
    local_pci_probe+0x68/0x110
    pci_call_probe+0x68/0x200
    pci_device_probe+0xbc/0x1a0
    really_probe+0x104/0x540
    __driver_probe_device+0xb4/0x230
    driver_probe_device+0x54/0x130
    __driver_attach+0x158/0x2b0
    bus_for_each_dev+0xa8/0x130
    driver_attach+0x34/0x50
    bus_add_driver+0x16c/0x300
    driver_register+0xa4/0x1b0
    __pci_register_driver+0x68/0x80
    mlx5_init+0xb8/0x100 [mlx5_core]
    do_one_initcall+0x60/0x300
    do_init_module+0x7c/0x2b0

At the time of LPAR dump, before kexec hands over control to kdump
kernel, DDWs (Dynamic DMA Windows) are scanned and added to the FDT.
For the SR-IOV case, default DMA window "ibm,dma-window" is removed from
the FDT and DDW added, for the device.

Now, kexec hands over control to the kdump kernel.

When the kdump kernel initializes, PCI busses are scanned and IOMMU
group/tables created, in pci_dma_bus_setup_pSeriesLP(). For the SR-IOV
case, there is no "ibm,dma-window". The original commit: b1fc44eaa9ba,
fixes the path where memory is pre-mapped (direct mapped) to the DDW.
When TCEs are direct mapped, there is no need to initialize IOMMU
tables.

iommu_table_setparms_lpar() only considers "ibm,dma-window" property
when initiallizing IOMMU table. In the scenario where TCEs are
dynamically allocated for SR-IOV, newly created IOMMU table is not
initialized. Later, when the device driver tries to enter TCEs for the
SR-IOV device, NULL pointer execption is thrown from iommu_area_alloc().

The fix is to initialize the IOMMU table with DDW property stored in the
FDT. There are 2 points to remember:

	1. For the dedicated adapter, kdump kernel would encounter both
	   default and DDW in FDT. In this case, DDW property is used to
	   initialize the IOMMU table.

	2. A DDW could be direct or dynamic mapped. kdump kernel would
	   initialize IOMMU table and mark the existing DDW as
	   "dynamic". This works fine since, at the time of table
	   initialization, iommu_table_clear() makes some space in the
	   DDW, for some predefined number of TCEs which are needed for
	   kdump to succeed.

Fixes: b1fc44eaa9ba ("pseries/iommu/ddw: Fix kdump to work in absence of ibm,dma-window")
Signed-off-by: Gaurav Batra &lt;gbatra@linux.vnet.ibm.com&gt;
Reviewed-by: Brian King &lt;brking@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240125203017.61014-1-gbatra@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries/iommu: DLPAR add doesn't completely initialize pci_controller</title>
<updated>2024-03-01T12:41:55Z</updated>
<author>
<name>Gaurav Batra</name>
</author>
<published>2024-02-15T22:18:33Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=46e36ebd5e00a148b67ed77c1d31675996f77c25'/>
<id>urn:sha1:46e36ebd5e00a148b67ed77c1d31675996f77c25</id>
<content type='text'>
[ Upstream commit a5c57fd2e9bd1c8ea8613a8f94fd0be5eccbf321 ]

When a PCI device is dynamically added, the kernel oopses with a NULL
pointer dereference:

  BUG: Kernel NULL pointer dereference on read at 0x00000030
  Faulting instruction address: 0xc0000000006bbe5c
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: rpadlpar_io rpaphp rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs xsk_diag bonding nft_compat nf_tables nfnetlink rfkill binfmt_misc dm_multipath rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_umad ib_iser libiscsi scsi_transport_iscsi ib_ipoib rdma_cm iw_cm ib_cm mlx5_ib ib_uverbs ib_core pseries_rng drm drm_panel_orientation_quirks xfs libcrc32c mlx5_core mlxfw sd_mod t10_pi sg tls ibmvscsi ibmveth scsi_transport_srp vmx_crypto pseries_wdt psample dm_mirror dm_region_hash dm_log dm_mod fuse
  CPU: 17 PID: 2685 Comm: drmgr Not tainted 6.7.0-203405+ #66
  Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries
  NIP:  c0000000006bbe5c LR: c000000000a13e68 CTR: c0000000000579f8
  REGS: c00000009924f240 TRAP: 0300   Not tainted  (6.7.0-203405+)
  MSR:  8000000000009033 &lt;SF,EE,ME,IR,DR,RI,LE&gt;  CR: 24002220  XER: 20040006
  CFAR: c000000000a13e64 DAR: 0000000000000030 DSISR: 40000000 IRQMASK: 0
  ...
  NIP sysfs_add_link_to_group+0x34/0x94
  LR  iommu_device_link+0x5c/0x118
  Call Trace:
   iommu_init_device+0x26c/0x318 (unreliable)
   iommu_device_link+0x5c/0x118
   iommu_init_device+0xa8/0x318
   iommu_probe_device+0xc0/0x134
   iommu_bus_notifier+0x44/0x104
   notifier_call_chain+0xb8/0x19c
   blocking_notifier_call_chain+0x64/0x98
   bus_notify+0x50/0x7c
   device_add+0x640/0x918
   pci_device_add+0x23c/0x298
   of_create_pci_dev+0x400/0x884
   of_scan_pci_dev+0x124/0x1b0
   __of_scan_bus+0x78/0x18c
   pcibios_scan_phb+0x2a4/0x3b0
   init_phb_dynamic+0xb8/0x110
   dlpar_add_slot+0x170/0x3b8 [rpadlpar_io]
   add_slot_store.part.0+0xb4/0x130 [rpadlpar_io]
   kobj_attr_store+0x2c/0x48
   sysfs_kf_write+0x64/0x78
   kernfs_fop_write_iter+0x1b0/0x290
   vfs_write+0x350/0x4a0
   ksys_write+0x84/0x140
   system_call_exception+0x124/0x330
   system_call_vectored_common+0x15c/0x2ec

Commit a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities
and allow blocking domains") broke DLPAR add of PCI devices.

The above added iommu_device structure to pci_controller. During
system boot, PCI devices are discovered and this newly added iommu_device
structure is initialized by a call to iommu_device_register().

During DLPAR add of a PCI device, a new pci_controller structure is
allocated but there are no calls made to iommu_device_register()
interface.

Fix is to register the iommu device during DLPAR add as well.

Fixes: a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains")
Signed-off-by: Gaurav Batra &lt;gbatra@linux.ibm.com&gt;
Reviewed-by: Brian King &lt;brking@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240215221833.4817-1-gbatra@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries: fix accuracy of stolen time</title>
<updated>2024-02-23T08:51:48Z</updated>
<author>
<name>Shrikanth Hegde</name>
</author>
<published>2024-02-13T05:26:35Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=8fd2674d43c96d051391ec32505382c9a5e18643'/>
<id>urn:sha1:8fd2674d43c96d051391ec32505382c9a5e18643</id>
<content type='text'>
commit cbecc9fcbbec60136b0180ba0609c829afed5c81 upstream.

powerVM hypervisor updates the VPA fields with stolen time data.
It currently reports enqueue_dispatch_tb and ready_enqueue_tb for
this purpose. In linux these two fields are used to report the stolen time.

The VPA fields are updated at the TB frequency. On powerPC its mostly
set at 512Mhz. Hence this needs a conversion to ns when reporting it
back as rest of the kernel timings are in ns. This conversion is already
handled in tb_to_ns function. So use that function to report accurate
stolen time.

Observed this issue and used an Capped Shared Processor LPAR(SPLPAR) to
simplify the experiments. In all these cases, 100% VP Load is run using
stress-ng workload. Values of stolen time is in percentages as reported
by mpstat. With the patch values are close to expected.

		6.8.rc1		+Patch
12EC/12VP	   0.0		   0.0
12EC/24VP	  25.7		  50.2
12EC/36VP	  37.3		  69.2
12EC/48VP	  38.5		  78.3

Fixes: 0e8a63132800 ("powerpc/pseries: Implement CONFIG_PARAVIRT_TIME_ACCOUNTING")
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Shrikanth Hegde &lt;sshegde@linux.ibm.com&gt;
Reviewed-by: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240213052635.231597-1-sshegde@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>Revert "powerpc/pseries/iommu: Fix iommu initialisation during DLPAR add"</title>
<updated>2024-02-23T08:51:36Z</updated>
<author>
<name>Michael Ellerman</name>
</author>
<published>2024-02-14T00:00:41Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=d4f762d6403f7419de90d7749fa83dd92ffb0e1d'/>
<id>urn:sha1:d4f762d6403f7419de90d7749fa83dd92ffb0e1d</id>
<content type='text'>
commit 1fba2bf8e9d5a27b7394856181b6200de7260b79 upstream.

This reverts commit ed8b94f6e0acd652ce69bd69d678a0c769172df8.

Gaurav reported that there are still problems with the patch and it
should be reverted pending a fuller fix.

Link: https://lore.kernel.org/all/4f6fc1ac-7a76-4447-9d0e-f55c0be373f8@linux.ibm.com/
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries/iommu: Fix iommu initialisation during DLPAR add</title>
<updated>2024-02-23T08:51:32Z</updated>
<author>
<name>Gaurav Batra</name>
</author>
<published>2024-01-22T22:24:07Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=12b55cfdd3ab91c70cc945cf8b5f45984ea0abf1'/>
<id>urn:sha1:12b55cfdd3ab91c70cc945cf8b5f45984ea0abf1</id>
<content type='text'>
[ Upstream commit ed8b94f6e0acd652ce69bd69d678a0c769172df8 ]

When a PCI device is dynamically added, the kernel oopses with a NULL
pointer dereference:

  BUG: Kernel NULL pointer dereference on read at 0x00000030
  Faulting instruction address: 0xc0000000006bbe5c
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: rpadlpar_io rpaphp rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs xsk_diag bonding nft_compat nf_tables nfnetlink rfkill binfmt_misc dm_multipath rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_umad ib_iser libiscsi scsi_transport_iscsi ib_ipoib rdma_cm iw_cm ib_cm mlx5_ib ib_uverbs ib_core pseries_rng drm drm_panel_orientation_quirks xfs libcrc32c mlx5_core mlxfw sd_mod t10_pi sg tls ibmvscsi ibmveth scsi_transport_srp vmx_crypto pseries_wdt psample dm_mirror dm_region_hash dm_log dm_mod fuse
  CPU: 17 PID: 2685 Comm: drmgr Not tainted 6.7.0-203405+ #66
  Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries
  NIP:  c0000000006bbe5c LR: c000000000a13e68 CTR: c0000000000579f8
  REGS: c00000009924f240 TRAP: 0300   Not tainted  (6.7.0-203405+)
  MSR:  8000000000009033 &lt;SF,EE,ME,IR,DR,RI,LE&gt;  CR: 24002220  XER: 20040006
  CFAR: c000000000a13e64 DAR: 0000000000000030 DSISR: 40000000 IRQMASK: 0
  ...
  NIP sysfs_add_link_to_group+0x34/0x94
  LR  iommu_device_link+0x5c/0x118
  Call Trace:
   iommu_init_device+0x26c/0x318 (unreliable)
   iommu_device_link+0x5c/0x118
   iommu_init_device+0xa8/0x318
   iommu_probe_device+0xc0/0x134
   iommu_bus_notifier+0x44/0x104
   notifier_call_chain+0xb8/0x19c
   blocking_notifier_call_chain+0x64/0x98
   bus_notify+0x50/0x7c
   device_add+0x640/0x918
   pci_device_add+0x23c/0x298
   of_create_pci_dev+0x400/0x884
   of_scan_pci_dev+0x124/0x1b0
   __of_scan_bus+0x78/0x18c
   pcibios_scan_phb+0x2a4/0x3b0
   init_phb_dynamic+0xb8/0x110
   dlpar_add_slot+0x170/0x3b8 [rpadlpar_io]
   add_slot_store.part.0+0xb4/0x130 [rpadlpar_io]
   kobj_attr_store+0x2c/0x48
   sysfs_kf_write+0x64/0x78
   kernfs_fop_write_iter+0x1b0/0x290
   vfs_write+0x350/0x4a0
   ksys_write+0x84/0x140
   system_call_exception+0x124/0x330
   system_call_vectored_common+0x15c/0x2ec

Commit a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities
and allow blocking domains") broke DLPAR add of PCI devices.

The above added iommu_device structure to pci_controller. During
system boot, PCI devices are discovered and this newly added iommu_device
structure is initialized by a call to iommu_device_register().

During DLPAR add of a PCI device, a new pci_controller structure is
allocated but there are no calls made to iommu_device_register()
interface.

Fix is to register the iommu device during DLPAR add as well.

Fixes: a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains")
Signed-off-by: Gaurav Batra &lt;gbatra@linux.ibm.com&gt;
[mpe: Trim oops and tweak some change log wording]
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240122222407.39603-1-gbatra@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries/memhp: Fix access beyond end of drmem array</title>
<updated>2024-01-25T23:44:37Z</updated>
<author>
<name>Nathan Lynch</name>
</author>
<published>2023-11-14T17:01:53Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=708a4b59baad96c4718dc0bd3a3427d3ab22fedc'/>
<id>urn:sha1:708a4b59baad96c4718dc0bd3a3427d3ab22fedc</id>
<content type='text'>
[ Upstream commit bd68ffce69f6cf8ddd3a3c32549d1d2275e49fc5 ]

dlpar_memory_remove_by_index() may access beyond the bounds of the
drmem lmb array when the LMB lookup fails to match an entry with the
given DRC index. When the search fails, the cursor is left pointing to
&amp;drmem_info-&gt;lmbs[drmem_info-&gt;n_lmbs], which is one element past the
last valid entry in the array. The debug message at the end of the
function then dereferences this pointer:

        pr_debug("Failed to hot-remove memory at %llx\n",
                 lmb-&gt;base_addr);

This was found by inspection and confirmed with KASAN:

  pseries-hotplug-mem: Attempting to hot-remove LMB, drc index 1234
  ==================================================================
  BUG: KASAN: slab-out-of-bounds in dlpar_memory+0x298/0x1658
  Read of size 8 at addr c000000364e97fd0 by task bash/949

  dump_stack_lvl+0xa4/0xfc (unreliable)
  print_report+0x214/0x63c
  kasan_report+0x140/0x2e0
  __asan_load8+0xa8/0xe0
  dlpar_memory+0x298/0x1658
  handle_dlpar_errorlog+0x130/0x1d0
  dlpar_store+0x18c/0x3e0
  kobj_attr_store+0x68/0xa0
  sysfs_kf_write+0xc4/0x110
  kernfs_fop_write_iter+0x26c/0x390
  vfs_write+0x2d4/0x4e0
  ksys_write+0xac/0x1a0
  system_call_exception+0x268/0x530
  system_call_vectored_common+0x15c/0x2ec

  Allocated by task 1:
   kasan_save_stack+0x48/0x80
   kasan_set_track+0x34/0x50
   kasan_save_alloc_info+0x34/0x50
   __kasan_kmalloc+0xd0/0x120
   __kmalloc+0x8c/0x320
   kmalloc_array.constprop.0+0x48/0x5c
   drmem_init+0x2a0/0x41c
   do_one_initcall+0xe0/0x5c0
   kernel_init_freeable+0x4ec/0x5a0
   kernel_init+0x30/0x1e0
   ret_from_kernel_user_thread+0x14/0x1c

  The buggy address belongs to the object at c000000364e80000
   which belongs to the cache kmalloc-128k of size 131072
  The buggy address is located 0 bytes to the right of
   allocated 98256-byte region [c000000364e80000, c000000364e97fd0)

  ==================================================================
  pseries-hotplug-mem: Failed to hot-remove memory at 0

Log failed lookups with a separate message and dereference the
cursor only when it points to a valid entry.

Signed-off-by: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Fixes: 51925fb3c5c9 ("powerpc/pseries: Implement memory hotplug remove in the kernel")
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20231114-pseries-memhp-fixes-v1-1-fb8f2bb7c557@linux.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>powerpc/pseries/vas: Migration suspend waits for no in-progress open windows</title>
<updated>2023-12-13T11:01:47Z</updated>
<author>
<name>Haren Myneni</name>
</author>
<published>2023-11-25T23:51:04Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=0cf72f7f14d12cb065c3d01954cf42fc5638aa69'/>
<id>urn:sha1:0cf72f7f14d12cb065c3d01954cf42fc5638aa69</id>
<content type='text'>
The hypervisor returns migration failure if all VAS windows are not
closed. During pre-migration stage, vas_migration_handler() sets
migration_in_progress flag and closes all windows from the list.
The allocate VAS window routine checks the migration flag, setup
the window and then add it to the list. So there is possibility of
the migration handler missing the window that is still in the
process of setup.

t1: Allocate and open VAS	t2: Migration event
    window

lock vas_pseries_mutex
If migration_in_progress set
  unlock vas_pseries_mutex
  return
open window HCALL
unlock vas_pseries_mutex
Modify window HCALL		lock vas_pseries_mutex
setup window			migration_in_progress=true
				Closes all windows from the list
				// May miss windows that are
				// not in the list
				unlock vas_pseries_mutex
lock vas_pseries_mutex		return
if nr_closed_windows == 0
  // No DLPAR CPU or migration
  add window to the list
  // Window will be added to the
  // list after the setup is completed
  unlock vas_pseries_mutex
  return
unlock vas_pseries_mutex
Close VAS window
// due to DLPAR CPU or migration
return -EBUSY

This patch resolves the issue with the following steps:
- Set the migration_in_progress flag without holding mutex.
- Introduce nr_open_wins_progress counter in VAS capabilities
  struct
- This counter tracks the number of open windows are still in
  progress
- The allocate setup window thread closes windows if the migration
  is set and decrements nr_open_window_progress counter
- The migration handler waits for no in-progress open windows.

The code flow with the fix is as follows:

t1: Allocate and open VAS       t2: Migration event
    window

lock vas_pseries_mutex
If migration_in_progress set
   unlock vas_pseries_mutex
   return
open window HCALL
nr_open_wins_progress++
// Window opened, but not
// added to the list yet
unlock vas_pseries_mutex
Modify window HCALL		migration_in_progress=true
setup window			lock vas_pseries_mutex
				Closes all windows from the list
				While nr_open_wins_progress {
				    unlock vas_pseries_mutex
lock vas_pseries_mutex		    sleep
if nr_closed_windows == 0	    // Wait if any open window in
or migration is not started	    // progress. The open window
   // No DLPAR CPU or migration	    // thread closes the window without
   add window to the list	    // adding to the list and return if
   nr_open_wins_progress--	    // the migration is in progress.
   unlock vas_pseries_mutex
   return
Close VAS window
nr_open_wins_progress--
unlock vas_pseries_mutex
return -EBUSY			    lock vas_pseries_mutex
				}
				unlock vas_pseries_mutex
				return

Fixes: 37e6764895ef ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni &lt;haren@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20231125235104.3405008-1-haren@linux.ibm.com

</content>
</entry>
<entry>
<title>powerpc/pseries/rtas-work-area: Fix rtas_work_area_reserve_arena() kernel-doc</title>
<updated>2023-11-07T02:13:44Z</updated>
<author>
<name>Nathan Lynch</name>
</author>
<published>2023-11-06T13:42:53Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=65083333d3d16b282674aeef5cce5c72226c05e0'/>
<id>urn:sha1:65083333d3d16b282674aeef5cce5c72226c05e0</id>
<content type='text'>
&gt;From a W=1 build:

&gt;&gt; arch/powerpc/platforms/pseries/rtas-work-area.c:189: warning: Function parameter or member 'limit' not
&gt;&gt; described in 'rtas_work_area_reserve_arena'

Add the missing description of the limit parameter.

Signed-off-by: Nathan Lynch &lt;nathanl@linux.ibm.com&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Closes: https://lore.kernel.org/oe-kbuild-all/202309131221.Bm1pg96n-lkp@intel.com/
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20231106-rtas-trivial-v1-1-61847655c51f@linux.ibm.com

</content>
</entry>
<entry>
<title>Merge tag 'powerpc-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux</title>
<updated>2023-11-03T20:07:39Z</updated>
<author>
<name>Linus Torvalds</name>
</author>
<published>2023-11-03T20:07:39Z</published>
<link rel='alternate' type='text/html' href='https://git.0xinfinity.dev/distro/kernel.git/commit/?id=707df298cbde200b939c70be2577b20775fe3345'/>
<id>urn:sha1:707df298cbde200b939c70be2577b20775fe3345</id>
<content type='text'>
Pull powerpc updates from Michael Ellerman:

 - Add support for KVM running as a nested hypervisor under development
   versions of PowerVM, using the new PAPR nested virtualisation API

 - Add support for the BPF prog pack allocator

 - A rework of the non-server MMU handling to support execute-only on
   all platforms

 - Some optimisations &amp; cleanups for the powerpc qspinlock code

 - Various other small features and fixes

Thanks to Aboorva Devarajan, Aditya Gupta, Amit Machhiwal, Benjamin
Gray, Christophe Leroy, Dr. David Alan Gilbert, Gaurav Batra, Gautam
Menghani, Geert Uytterhoeven, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Julia Lawall, Kautuk Consul, Kuan-Wei Chiu, Michael
Neuling, Minjie Du, Muhammad Muzammil, Naveen N Rao, Nicholas Piggin,
Nick Child, Nysal Jan K.A, Peter Lafreniere, Rob Herring, Sachin Sant,
Sebastian Andrzej Siewior, Shrikanth Hegde, Srikar Dronamraju, Stanislav
Kinsburskii, Vaibhav Jain, Wang Yufen, Yang Yingliang, and Yuan Tan.

* tag 'powerpc-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (100 commits)
  powerpc/vmcore: Add MMU information to vmcoreinfo
  Revert "powerpc: add `cur_cpu_spec` symbol to vmcoreinfo"
  powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free]
  powerpc/bpf: rename powerpc64_jit_data to powerpc_jit_data
  powerpc/bpf: implement bpf_arch_text_invalidate for bpf_prog_pack
  powerpc/bpf: implement bpf_arch_text_copy
  powerpc/code-patching: introduce patch_instructions()
  powerpc/32s: Implement local_flush_tlb_page_psize()
  powerpc/pseries: use kfree_sensitive() in plpks_gen_password()
  powerpc/code-patching: Perform hwsync in __patch_instruction() in case of failure
  powerpc/fsl_msi: Use device_get_match_data()
  powerpc: Remove cpm_dp...() macros
  powerpc/qspinlock: Rename yield_propagate_owner tunable
  powerpc/qspinlock: Propagate sleepy if previous waiter is preempted
  powerpc/qspinlock: don't propagate the not-sleepy state
  powerpc/qspinlock: propagate owner preemptedness rather than CPU number
  powerpc/qspinlock: stop queued waiters trying to set lock sleepy
  powerpc/perf: Fix disabling BHRB and instruction sampling
  powerpc/trace: Add support for HAVE_FUNCTION_ARG_ACCESS_API
  powerpc/tools: Pass -mabi=elfv2 to gcc-check-mprofile-kernel.sh
  ...
</content>
</entry>
</feed>
