Commit Graph

933287 Commits

Author SHA1 Message Date
Nicholas Piggin
aa65ff6b18 powerpc/64s: Implement queued spinlocks and rwlocks
These have shown significantly improved performance and fairness when
spinlock contention is moderate to high on very large systems.

With this series including subsequent patches, on a 16 socket 1536
thread POWER9, a stress test such as same-file open/close from all
CPUs gets big speedups, 11620op/s aggregate with simple spinlocks vs
384158op/s (33x faster), where the difference in throughput between
the fastest and slowest thread goes from 7x to 1.4x.

Thanks to the fast path being identical in terms of atomics and
barriers (after a subsequent optimisation patch), single threaded
performance is not changed (no measurable difference).

On smaller systems, performance and fairness seems to be generally
improved. Using dbench on tmpfs as a test (that starts to run into
kernel spinlock contention), a 2-socket OpenPOWER POWER9 system was
tested with bare metal and KVM guest configurations. Results can be
found here:

https://github.com/linuxppc/issues/issues/305#issuecomment-663487453

Observations are:

- Queued spinlocks are equal when contention is insignificant, as
  expected and as measured with microbenchmarks.

- When there is contention, on bare metal queued spinlocks have better
  throughput and max latency at all points.

- When virtualised, queued spinlocks are slightly worse approaching
  peak throughput, but significantly better throughput and max latency
  at all points beyond peak, until queued spinlock maximum latency
  rises when clients are 2x vCPUs.

The regressions haven't been analysed very well yet, there are a lot
of things that can be tuned, particularly the paravirtualised locking,
but the numbers already look like a good net win even on relatively
small systems.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131423.1362108-4-npiggin@gmail.com
2020-07-27 00:01:23 +10:00
Nicholas Piggin
12d0b9d6c8 powerpc: Move spinlock implementation to simple_spinlock
To prepare for queued spinlocks. This is a simple rename except to
update preprocessor guard name and a file reference.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131423.1362108-3-npiggin@gmail.com
2020-07-26 23:34:26 +10:00
Nicholas Piggin
20d444d06f powerpc/pseries: Move some PAPR paravirt functions to their own file
These functions will be used by the queued spinlock implementation,
and may be useful elsewhere too, so move them out of spinlock.h.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131423.1362108-2-npiggin@gmail.com
2020-07-26 23:34:26 +10:00
Srikar Dronamraju
dbce456280 powerpc/numa: Limit possible nodes to within num_possible_nodes
MAX_NUMNODES is a theoretical maximum number of nodes thats is
supported by the kernel. Device tree properties exposes the number of
possible nodes on the current platform. The kernel would detected this
and would use it for most of its resource allocations. If the platform
now increases the nodes to over what was already exposed, then it may
lead to inconsistencies. Hence limit it to the already exposed nodes.

Suggested-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724105809.24733-1-srikar@linux.vnet.ibm.com
2020-07-26 23:34:25 +10:00
Finn Thain
3327e58a04 macintosh/via-macii: Clarify definition of macii_init()
The function prototype correctly specifies the 'static' storage class.
Let the function definition match the declaration for better readability.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c025aed0b1506399b73ff1d1bfa40ed641fcb3e3.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
046ace8256 macintosh/via-macii: Use the stack for reset request storage
The adb_request struct can be stored on the stack because the request
is synchronous and is completed before the function returns.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a40f80dde90991757007b6962c386a208c970586.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
5c0c15a195 macintosh/via-macii: Use unsigned type for autopoll_devs variable
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ca5be30ba745c08c2b7a1f0618f99c61b303e983.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
f87a162572 macintosh/via-macii: Use bool type for reading_reply variable
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/779551219a11b19e574dfcd87e4ef60af08c4fc3.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
624cf5b538 macintosh/via-macii: Handle poll replies correctly
Userspace applications may use /dev/adb to send Talk requests. Such
requests always have req->reply_expected == 1. The same is true of Talk
requests sent by the kernel, except for poll requests queued internally
by the via-macii driver. Those requests have req->reply_expected == 0.

Consequently, poll reply packets get treated like autopoll reply packets.
(It doesn't make sense to try to distinguish them.) Always enter 'reading'
state after a poll request, so that the reply gets collected and passed
to adb_input(), and none go missing.

All Talk replies passed to adb_input() come from polling or autopolling,
so call adb_input() with the autopoll parameter set to 1.

Fixes: d95fd5fce8 ("m68k: Mac II ADB fixes") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/754cddfa045e5bfa53e5da199831de02e7d2f27f.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
b16b67689b macintosh/via-macii: Remove read_done state
The driver state machine may enter the 'read_done' state when leaving the
'idle' or 'reading' state. This transition is pointless, as is the extra
interrupt it requires. The interrupt is produced by the transceiver
(even when it has no data to send) because an extra EVEN/ODD toggle
was signalled by the driver. Drop the extra state to simplify the code.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0253194363af4426f9788796811a6a29fb87c713.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
b4d76c28ec macintosh/via-macii: Handle /CTLR_IRQ signal correctly
I'm told that the /CTLR_IRQ signal from the ADB transceiver gets
interpreted by MacOS to mean SRQ, bus timeout or end-of-packet depending
on the circumstances, and that Linux's via-macii driver does not
correctly interpret this signal.

Instead, the via-macii driver interprets certain received byte values
(0x00 and 0xFF) as signalling end of packet and bus timeout
(respectively). Problem is, those values can also appear under other
circumstances.

This patch changes the bus timeout, end of packet and SRQ detection logic
to bring it closer to the logic that MacOS reportedly uses.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2") # v5.0+
Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6541fda1d8db3ae87c3abe17d189a10dc96e2382.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
f93bfeb552 macintosh/via-macii: Poll the device most likely to respond
Poll the most recently polled device by default, rather than the lowest
device address that happens to be enabled in autopoll_devs. This improves
input latency. Re-use macii_queue_poll() rather than duplicate that logic.
This eliminates a static struct and function.

Fixes: d95fd5fce8 ("m68k: Mac II ADB fixes") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5836f80886ebcfbe5be5fb7e0dc49feed6469712.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:25 +10:00
Finn Thain
59ea38f6b3 macintosh/via-macii: Access autopoll_devs when inside lock
The interrupt handler should be excluded when accessing the autopoll_devs
variable.

Fixes: d95fd5fce8 ("m68k: Mac II ADB fixes") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5952dd8a9bc9de90f1acc4790c51dd42b4c98065.1593318192.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
c66da95a39 macintosh/adb-iop: Implement SRQ autopolling
The adb_driver.autopoll method is needed during ADB bus scan and device
address assignment. Implement this method so that the IOP's list of
device addresses can be updated. When the list is empty, disable SRQ
autopolling.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0fb7fdcd99d7820bb27faf1f27f7f6f1923914ef.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
e2954e5f72 macintosh/adb-iop: Implement sending -> idle state transition
On leaving the 'sending' state, proceed to the 'idle' state if no reply is
expected. Drop redundant test for adb_iop_state == sending && current_req.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6991996dd4aaf0b52cfd650172bf0f6fbe37a452.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
32226e8170 macintosh/adb-iop: Implement idle -> sending state transition
In the present algorithm, the 'idle' state transition does not take
place until there's a bus timeout. Once idle, the driver does not
automatically proceed with the next request.

Change the algorithm so that queued ADB requests will be sent as soon as
the driver becomes idle. This is to take place after the current IOP
message is completed.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/dedcdfc62f43e85cc4c2a8d211a7e2fec7bc7c1a.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
56b732edda macintosh/adb-iop: Resolve static checker warnings
drivers/macintosh/adb-iop.c:215:28: warning: Using plain integer as NULL pointer
drivers/macintosh/adb-iop.c:170:5: warning: symbol 'adb_iop_probe' was not declared. Should it be static?
drivers/macintosh/adb-iop.c:177:5: warning: symbol 'adb_iop_init' was not declared. Should it be static?
drivers/macintosh/adb-iop.c:184:5: warning: symbol 'adb_iop_send_request' was not declared. Should it be static?
drivers/macintosh/adb-iop.c:230:5: warning: symbol 'adb_iop_autopoll' was not declared. Should it be static?
drivers/macintosh/adb-iop.c:236:6: warning: symbol 'adb_iop_poll' was not declared. Should it be static?
drivers/macintosh/adb-iop.c:241:5: warning: symbol 'adb_iop_reset_bus' was not declared. Should it be static?

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/25edf4450abd20e002b166ba3a11189dc1efa906.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
aac840eca8 macintosh/adb-iop: Access current_req and adb_iop_state when inside lock
Drop the redundant local_irq_save/restore() from adb_iop_start() because
the caller has to do it anyway. This is the pattern used in via-macii.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bbe32b087c7e04d68e2425f6a2df4a414d167c32.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
303511edb8 macintosh/adb-iop: Adopt bus reset algorithm from via-macii driver
This algorithm is slightly shorter and avoids the surprising
adb_iop_start() call in adb_iop_poll().

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b63d56ecb6e75f11a0bf02231f3b2db656a528a3.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
ff785e179f macintosh/adb-iop: Correct comment text
This patch improves comment style and corrects some misunderstandings
in the text.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/996f835d2f3d90baaaf9ee954e252d06e8886c6f.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:24 +10:00
Finn Thain
8384c82ab0 macintosh/adb-iop: Remove dead and redundant code
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7720ffb559c334504e16b24d9c2f3b8973d2d674.1590880623.git.fthain@telegraphics.com.au
2020-07-26 23:34:23 +10:00
Athira Rajeev
65156f2b1d powerpc/perf: Initialize power10 PMU registers in cpu setup routine
Initialize Monitor Mode Control Register 3 (MMCR3)
SPR which is new in power10. For PowerISA v3.1, BHRB disable
is controlled via Monitor Mode Control Register A (MMCRA) bit,
namely "BHRB Recording Disable (BHRBRD)". This patch also initializes
MMCRA BHRBRD to disable BHRB feature at boot for power10.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1595489557-2047-1-git-send-email-atrajeev@linux.vnet.ibm.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
84d8505ed1 powerpc/powernv/sriov: Remove vfs_expanded
Previously iov->vfs_expanded was used for two purposes.

1) To work out how much we need to multiple the per-VF BAR size to figure
   out the total space required for the IOV BAR.

2) To indicate that IOV is not usable with this device (vfs_expanded == 0).

We don't really need the field for either since the multiple in 1) is
always the number PEs supported by the PHB. Similarly, we don't really need
it in 2) either since the IOV data field will be NULL if we can't use IOV
with the device.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-16-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
4c51f3e1e8 powerpc/powernv/sriov: Make single PE mode a per-BAR setting
Using single PE BARs to map an SR-IOV BAR is really a choice about what
strategy to use when mapping a BAR. It doesn't make much sense for this to
be a global setting since a device might have one large BAR which needs to
be mapped with single PE windows and another smaller BAR that can be mapped
with a regular segmented window. Make the segmented vs single decision a
per-BAR setting and clean up the logic that decides which mode to use.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-15-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
a0be516f81 powerpc/powernv/sriov: Refactor M64 BAR setup
Split up the logic so that we have one branch that handles setting up a
segmented window and another that handles setting up single PE windows for
each VF.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-14-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
39efc03e3e powerpc/powernv/sriov: Move M64 BAR allocation into a helper
I want to refactor the loop this code is currently inside of. Hoist it on
out.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-13-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
052da31d45 powerpc/powernv/sriov: De-indent setup and teardown
Remove the IODA2 PHB checks. We already assume IODA2 in several places so
there's not much point in wrapping most of the setup and teardown process
in an if block.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-12-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
d29a2488d2 powerpc/powernv/sriov: Drop iov->pe_num_map[]
Currently the iov->pe_num_map[] does one of two things depending on
whether single PE mode is being used or not. When it is, this contains an
array which maps a vf_index to the corresponding PE number. When single PE
mode is not being used this contains a scalar which is the base PE for the
set of enabled VFs (for for VFn is base + n).

The array was necessary because when calling pnv_ioda_alloc_pe() there is
no guarantee that the allocated PEs would be contigious. We can now
allocate contigious blocks of PEs so this is no longer an issue. This
allows us to drop the if (single_mode) {} .. else {} block scattered
through the SR-IOV code which is a nice clean up.

This also fixes a bug in pnv_pci_sriov_disable() which is the non-atomic
bitmap_clear() to manipulate the PE allocation map. Other users of the map
assume it will be accessed with atomic ops.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-11-oohall@gmail.com
2020-07-26 23:34:23 +10:00
Oliver O'Halloran
a4bc676ed5 powerpc/powernv/pci: Refactor pnv_ioda_alloc_pe()
Rework the PE allocation logic to allow allocating blocks of PEs rather
than individually. We'll use this to allocate contigious blocks of PEs for
the SR-IOVs.

This patch also adds code to pnv_ioda_alloc_pe() and pnv_ioda_reserve_pe() to
use the existing, but unused, phb->pe_alloc_mutex. Currently these functions
use atomic bit ops to release a currently allocated PE number. However,
the pnv_ioda_alloc_pe() wants to have exclusive access to the bit map while
scanning for hole large enough to accomodate the allocation size.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-10-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
a610d35cc8 powerpc/powernv/sriov: Factor out M64 BAR setup
The sequence required to use the single PE BAR mode is kinda janky and
requires a little explanation. The API was designed with P7-IOC style
windows where the setup process is something like:

1. Configure the window start / end address
2. Enable the window
3. Map the segments of each window to the PE

For Single PE BARs the process is:

1. Set the PE for segment zero on a disabled window
2. Set the range
3. Enable the window

Move the OPAL calls into their own helper functions where the quirks can be
contained.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-9-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
ad9add529d powerpc/powernv/sriov: Simplify used window tracking
No need for the multi-dimensional arrays, just use a bitmap.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-8-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
fac248f811 powerpc/powernv/sriov: Rename truncate_iov
This prevents SR-IOV being used by making the SR-IOV BAR resources
unallocatable. Rename it to reflect what it actually does.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-7-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
ff79e11af0 powerpc/powernv/sriov: Explain how SR-IOV works on PowerNV
SR-IOV support on PowerNV is a byzantine maze of hooks. I have no idea
how anyone is supposed to know how it works except through a lot of
stuffering. Write up some docs about the overall story to help out
the next sucker^Wperson who needs to tinker with it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-6-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
37b59ef08c powerpc/powernv/sriov: Move SR-IOV into a separate file
pci-ioda.c is getting a bit unwieldly due to the amount of stuff jammed in
there. The SR-IOV support can be extracted easily enough and is mostly
standalone, so move it into a separate file.

This patch also moves the PowerNV SR-IOV specific fields from pci_dn and
moves them into a platform specific structure. I'm not sure how they ended
up in there in the first place, but leaking platform specifics into common
code has proven to be a terrible idea so far so lets stop doing that.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-5-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
369633654f powerpc/powernv/pci: Initialise M64 for IODA1 as a 1-1 window
We pre-configure the m64 window for IODA1 as a 1-1 segment-PE mapping,
similar to PHB3. Currently the actual mapping of segments occurs in
pnv_ioda_pick_m64_pe(), but we can move it into pnv_ioda1_init_m64() and
drop the IODA1 specific code paths in the PE setup / teardown.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-4-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
01e12629af powerpc/powernv/pci: Add explicit tracking of the DMA setup state
There's an optimisation in the PE setup which skips performing DMA
setup for a PE if we only have bridges in a PE. The assumption being
that only "real" devices will DMA to system memory, which is probably
fair. However, if we start off with only bridge devices in a PE then
add a non-bridge device the new device won't be able to use DMA because
we never configured it.

Fix this (admittedly pretty weird) edge case by tracking whether we've done
the DMA setup for the PE or not. If a non-bridge device is added to the PE
(via rescan or hotplug, or whatever) we can set up DMA on demand.

This also means the only remaining user of the old "DMA Weight" code is
the IODA1 DMA setup code that it was originally added for, which is good.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-3-oohall@gmail.com
2020-07-26 23:34:22 +10:00
Oliver O'Halloran
7a52ffabe8 powerpc/powernv/pci: Always tear down DMA windows on PE release
Currently we have these two functions:

	pnv_pci_ioda2_release_dma_pe(), and
	pnv_pci_ioda2_release_pe_dma()

The first is used when tearing down VF PEs and the other is used for normal
devices. There's very little difference between the two though. The latter
(non-VF) will skip a call to pnv_pci_ioda2_unset_window() unless
CONFIG_IOMMU_API=y is set. There's no real point in doing this so fold the
two together.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-2-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
5609ffddd1 powerpc/powernv/pci: Add pci_bus_to_pnvhb() helper
Add a helper to go from a pci_bus structure to the pnv_phb that hosts
that bus. There's a lot of instances of the following pattern:

	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
	struct pnv_phb *phb = hose->private_data;

Without any other uses of the pci_controller inside the function. This
is hard to read since it requires you to memorise the contents of the
private data fields and kind of error prone since it involves blindly
assigning a void pointer. Add a helper to make it more concise and
explicit.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-1-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
a131bfc69b powerpc/eeh: Move PE tree setup into the platform
The EEH core has a concept of a "PE tree" to support PowerNV. The PE tree
follows the PCI bus structures because a reset asserted on an upstream
bridge will be propagated to the downstream bridges. On pseries there's a
1-1 correspondence between what the guest sees are a PHB and a PE so the
"tree" is really just a single node.

Current the EEH core is reponsible for setting up this PE tree which it
does by traversing the pci_dn tree. The structure of the pci_dn tree
matches the bus tree on PowerNV which leads to the PE tree being "correct"
this setup method doesn't make a whole lot of sense and it's actively
confusing for the pseries case where it doesn't really do anything.

We want to remove the dependence on pci_dn anyway so this patch move
choosing where to insert a new PE into the platform code rather than
being part of the generic EEH code. For PowerNV this simplifies the
tree building logic and removes the use of pci_dn. For pseries we
keep the existing logic. I'm not really convinced it does anything
due to the 1-1 PE-to-PHB correspondence so every device under that
PHB should be in the same PE, but I'd rather not remove it entirely
until we've had a chance to look at it more deeply.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-14-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
31595ae5ae powerpc/eeh: Drop pdn use in eeh_pe_tree_insert()
This is mostly just to make the subsequent diffs less noisy. No functional
changes.

One thing that needs calling out is the removal of the "config_addr"
variable and replacing it with edev->bdfn. The contents of edev->bdfn are
the same, however it's worth pointing out that what RTAS calls a
"config_addr" isn't the same as the bdfn. The config_addr is supposed to
be: <bus><devfn><reg> with each field being an 8 bit number. Various parts
of the EEH code use BDFN and "config_addr" as interchangeable quantities
even though they aren't really.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-13-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
d923ab7a96 powerpc/eeh: Rename eeh_{add_to|remove_from}_parent_pe()
The naming of eeh_{add_to|remove_from}_parent_pe() doesn't really reflect
what they actually do. If the PE referred to be edev->pe_config_addr
already exists under that PHB then the edev is added to that PE. However,
if the PE doesn't exist the a new one is created for the edev.

The bulk of the implementation of eeh_add_to_parent_pe() covers that
second case. Similarly, most of eeh_remove_from_parent_pe() is
determining when it's safe to delete a PE.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-12-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
768a42845b powerpc/eeh: Remove class code field from edev
The edev->class_code field is never referenced anywhere except for the
platform specific probe functions. The same information is available in
the pci_dev for PowerNV and in the pci_dn on pseries so we can remove
the field.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-11-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
1a303d8844 powerpc/eeh: Remove spurious use of pci_dn in eeh_dump_dev_log
Retrieve the domain, bus, device, and function numbers from the edev.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-10-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
17d2a48704 powerpc/eeh: Pass eeh_dev to eeh_ops->{read|write}_config()
Mechanical conversion of the eeh_ops interfaces to use eeh_dev to reference
a specific device rather than pci_dn. No functional changes.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-9-oohall@gmail.com
2020-07-26 23:34:21 +10:00
Oliver O'Halloran
8225d543dc powerpc/eeh: Pass eeh_dev to eeh_ops->resume_notify()
Mechanical conversion of the eeh_ops interfaces to use eeh_dev to reference
a specific device rather than pci_dn. No functional changes.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-8-oohall@gmail.com
2020-07-26 23:34:20 +10:00
Oliver O'Halloran
0c2c76523c powerpc/eeh: Pass eeh_dev to eeh_ops->restore_config()
Mechanical conversion of the eeh_ops interfaces to use eeh_dev to reference
a specific device rather than pci_dn. No functional changes.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-7-oohall@gmail.com
2020-07-26 23:34:20 +10:00
Oliver O'Halloran
21b43bd59c powerpc/eeh: Remove VF config space restoration
There's a bunch of strange things about this code. First up is that none of
the fields being written to are functional for a VF. The SR-IOV
specification lists then as "Reserved, but OS should preserve" so writing
new values to them doesn't do anything and is clearly wrong from a
correctness perspective.

However, since VFs are designed to be managed by the OS there is an
argument to be made that we should be saving and restoring some parts of
config space. We already sort of do that by saving the first 64 bytes of
config space in the eeh_dev (see eeh_dev->config_space[]). This is
inadequate since it doesn't even consider saving and restoring the PCI
capability structures. However, this is a problem with EEH in general and
that needs to be fixed for non-VF devices too.

There's no real reason to keep around this around so delete it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-6-oohall@gmail.com
2020-07-26 23:34:20 +10:00
Oliver O'Halloran
a40db93431 powerpc/eeh: Kill off eeh_ops->get_pe_addr()
This is used in precisely one place which is in pseries specific platform
code.  There's no need to have the callback in eeh_ops since the platform
chooses the EEH PE addresses anyway. The PowerNV implementation has always
been a stub too so remove it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-5-oohall@gmail.com
2020-07-26 23:34:20 +10:00
Oliver O'Halloran
c408ce9075 powerpc/pseries: Stop using pdn->pe_number
The pci_dn->pe_number field is mainly used to track the IODA PE number of a
device on PowerNV. At some point it grew a user in the pseries SR-IOV
support which muddies the waters a bit, so remove it.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-4-oohall@gmail.com
2020-07-26 23:34:20 +10:00
Oliver O'Halloran
dffa91539e powerpc/eeh: Move vf_index out of pci_dn and into eeh_dev
Drivers that do not support the PCI error handling callbacks are handled by
tearing down the device and re-probing them. If the device being removed is
a virtual function then we need to know the VF index so it can be removed
using the pci_iov_{add|remove}_virtfn() API.

Currently this is handled by looking up the pci_dn, and using the vf_index
that was stashed there when the pci_dn for the VF was created in
pcibios_sriov_enable(). We would like to eliminate the use of pci_dn
outside of pseries though so we need to provide the generic EEH code with
some other way to find the vf_index.

The easiest thing to do here is move the vf_index field out of pci_dn and
into eeh_dev.  Currently pci_dn and eeh_dev are allocated and initialized
together so this is a fairly minimal change in preparation for splitting
pci_dn and eeh_dev in the future.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200725081231.39076-3-oohall@gmail.com
2020-07-26 23:34:20 +10:00