Commit Graph

503 Commits (eab9e9629c8f3c0ce87f7bcad82176f55029a640)

Author SHA1 Message Date
Richard Henderson fdbc2b5722 tcg: Add EXCP_ATOMIC
When we cannot emulate an atomic operation within a parallel
context, this exception allows us to stop the world and try
again in a serial context.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-10-26 08:29:00 -07:00
Peter Maydell c43e853afe x86 and CPU queue, 2016-10-24
x2APIC support to APIC code, cpu_exec_init() refactor on all
 architectures, and other x86 changes.
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Merge remote-tracking branch 'remotes/ehabkost/tags/x86-pull-request' into staging

x86 and CPU queue, 2016-10-24

x2APIC support to APIC code, cpu_exec_init() refactor on all
architectures, and other x86 changes.

# gpg: Signature made Mon 24 Oct 2016 20:51:14 BST
# gpg:                using RSA key 0x2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF  D1AA 2807 936F 984D C5A6

* remotes/ehabkost/tags/x86-pull-request:
  exec: call cpu_exec_exit() from a CPU unrealize common function
  exec: move cpu_exec_init() calls to realize functions
  exec: split cpu_exec_init()
  pc: q35: Bump max_cpus to 288
  pc: Require IRQ remapping and EIM if there could be x2APIC CPUs
  pc: Add 'etc/boot-cpus' fw_cfg file for machine with more than 255 CPUs
  Increase MAX_CPUMASK_BITS from 255 to 288
  pc: Clarify FW_CFG_MAX_CPUS usage comment
  pc: kvm_apic: Pass APIC ID depending on xAPIC/x2APIC mode
  pc: apic_common: Reset APIC ID to initial ID when switching into x2APIC mode
  pc: apic_common: Restore APIC ID to initial ID on reset
  pc: apic_common: Extend APIC ID property to 32bit
  pc: Leave max apic_id_limit only in legacy cpu hotplug code
  acpi: cphp: Force switch to modern cpu hotplug if APIC ID > 254
  pc: acpi: x2APIC support for SRAT table
  pc: acpi: x2APIC support for MADT table and _MAT method

Conflicts:
	target-arm/cpu.c

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-10-25 10:25:27 +01:00
Laurent Vivier ce5b1bbf62 exec: move cpu_exec_init() calls to realize functions
Modify all CPUs to call it from XXX_cpu_realizefn() function.

Remove all the cannot_destroy_with_object_finalize_yet as
unsafe references have been moved to cpu_exec_realizefn().
(tested with QOM command provided by commit 4c315c27)

for arm:

Setting of cpu->mp_affinity is moved from arm_cpu_initfn()
to arm_cpu_realizefn() as setting of cpu_index is now done
in cpu_exec_realizefn(). To avoid to overwrite an user defined
value, we set it to an invalid value by default, and update
it in realize function only if the value is still invalid.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2016-10-24 17:29:16 -02:00
Peter Maydell 20bccb82ff cpu: Support a target CPU having a variable page size
Support target CPUs having a page size which isn't knownn
at compile time. To use this, the CPU implementation should:
 * define TARGET_PAGE_BITS_VARY
 * not define TARGET_PAGE_BITS
 * define TARGET_PAGE_BITS_MIN to the smallest value it
   might possibly want for TARGET_PAGE_BITS
 * call set_preferred_target_page_bits() in its realize
   function to indicate the actual preferred target page
   size for the CPU (and report any error from it)

In CONFIG_USER_ONLY, the CPU implementation should continue
to define TARGET_PAGE_BITS appropriately for the guest
OS page size.

Machines which want to take advantage of having the page
size something larger than TARGET_PAGE_BITS_MIN must
set the MachineClass minimum_page_bits field to a value
which they guarantee will be no greater than the preferred
page size for any CPU they create.

Note that changing the target page size by setting
minimum_page_bits is a migration compatibility break
for that machine.

For debugging purposes, attempts to use TARGET_PAGE_SIZE
before it has been finally confirmed will assert.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-10-24 16:26:49 +01:00
Paolo Bonzini 9a54635dcb memory: add a per-AddressSpace list of listeners
This speeds up MEMORY_LISTENER_CALL noticeably.  Right now,
with many PCI devices you have N regions added to M AddressSpaces
(M = # PCI devices with bus-master enabled) and each call looks
up the whole listener list, with at least M listeners in it.
Because most of the regions in N are BARs, which are also roughly
proportional to M, the whole thing is O(M^3).  This changes it
to O(M^2), which is the best we can do without rewriting the
whole thing.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-24 15:27:19 +02:00
Paolo Bonzini d45fa784cd memory: eliminate global MemoryListeners
There is none, so just drop the code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-24 15:27:19 +02:00
Dr. David Alan Gilbert 863e9621c5 RAMBlocks: Store page size
Store the page size in each RAMBlock, we need it later.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2016-10-13 17:23:53 +02:00
Sergey Fedorov 3359baad36 tcg: Make tb_flush() thread safe
Use async_safe_run_on_cpu() to make tb_flush() thread safe.  This is
possible now that code generation does not happen in the middle of
execution.

It can happen that multiple threads schedule a safe work to flush the
translation buffer. To keep statistics and debugging output sane, always
check if the translation buffer has already been flushed.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
[AJB: minor re-base fixes]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <1470158864-17651-13-git-send-email-alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini 267f685b8b cpus-common: move CPU list management to common code
Add a mutex for the CPU list to system emulation, as it will be used to
manage safe work.  Abstract manipulation of the CPU list in new functions
cpu_list_add and cpu_list_remove.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:29 +02:00
Paolo Bonzini 9c1f8f4493 migration: sync all address spaces
Migrating a VM during reboot sometimes results in differences
between the source and destination in the SMRAM area.

This is because migration_bitmap_sync() only fetches from KVM
the dirty log of address_space_memory.  SMRAM memory slots
are ignored and the modifications to SMRAM are not sent to the
destination.

Reported-by: He Rongguang <herongguang.he@huawei.com>
Reviewed-by: He Rongguang <herongguang.he@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:29 +02:00
Peter Xu 5bf3d31903 memory: introduce IOMMUOps.notify_flag_changed
The new interface can be used to replace the old notify_started() and
notify_stopped(). Meanwhile it provides explicit flags so that IOMMUs
can know what kind of notifications it is requested for.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1474606948-14391-3-git-send-email-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 09:00:04 +02:00
Peter Xu cdb3081269 memory: introduce IOMMUNotifier and its caps
IOMMU Notifier list is used for notifying IO address mapping changes.
Currently VFIO is the only user.

However it is possible that future consumer like vhost would like to
only listen to part of its notifications (e.g., cache invalidations).

This patch introduced IOMMUNotifier and IOMMUNotfierFlag bits for a
finer grained control of it.

IOMMUNotifier contains a bitfield for the notify consumer describing
what kind of notification it is interested in. Currently two kinds of
notifications are defined:

- IOMMU_NOTIFIER_MAP:    for newly mapped entries (additions)
- IOMMU_NOTIFIER_UNMAP:  for entries to be removed (cache invalidates)

When registering the IOMMU notifier, we need to specify one or multiple
types of messages to listen to.

When notifications are triggered, its type will be checked against the
notifier's type bits, and only notifiers with registered bits will be
notified.

(For any IOMMU implementation, an in-place mapping change should be
 notified with an UNMAP followed by a MAP.)

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1474606948-14391-2-git-send-email-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 08:59:16 +02:00
Richard Henderson 01ecaf438b tcg: Merge GETPC and GETRA
The return address argument to the softmmu template helpers was
confused.  In the legacy case, we wanted to indicate that there
is no return address, and so passed in NULL.  However, we then
immediately subtracted GETPC_ADJ from NULL, resulting in a non-zero
value, indicating the presence of an (invalid) return address.

Push the GETPC_ADJ subtraction down to the only point it's required:
immediately before use within cpu_restore_state_from_tb, after all
NULL pointer checks have been completed.

This makes GETPC and GETRA identical.  Remove GETRA as the lesser
used macro, replacing all uses with GETPC.

Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-09-16 08:12:11 -07:00
Paolo Bonzini 6d21e4208f tcg: Prepare TB invalidation for lockless TB lookup
When invalidating a translation block, set an invalid flag into the
TranslationBlock structure first.  It is also necessary to check whether
the target TB is still valid after acquiring 'tb_lock' but before calling
tb_add_jump() since TB lookup is to be performed out of 'tb_lock' in
future. Note that we don't have to check 'last_tb'; an already invalidated
TB will not be executed anyway and it is thus safe to patch it.

Suggested-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-13 19:08:43 +02:00
Richard Henderson dcb8e75870 tcg: Reorg TCGOp chaining
Instead of using -1 as end of chain, use 0, and link through the 0
entry as a fully circular double-linked list.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:18 +05:30
Peter Maydell d9fe91d868 linux-user: Use correct alignment for long long on i386 guests
For i386, the ABI specifies that 'long long' (8 byte values)
need only be 4 aligned, but we were requiring them to be
8-aligned. This meant we were laying out the target_epoll_event
structure wrongly. Add a suitable ifdef to abitypes.h to
specify the i386-specific alignment requirement.

Reported-by: Icenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-08-04 16:34:59 +03:00
Igor Mammedov 1bc7e522d9 exec: Reduce CONFIG_USER_ONLY ifdeffenery
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2016-07-26 15:31:58 -03:00
Markus Armbruster 175de52487 Clean up decorations and whitespace around header guards
Cleaned up with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:20:46 +02:00
Markus Armbruster 2a6a4076e1 Clean up ill-advised or unusual header guards
Cleaned up with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:20:46 +02:00
Markus Armbruster 121d07125b Clean up header guards that don't match their file name
Header guard symbols should match their file name to make guard
collisions less likely.  Offenders found with
scripts/clean-header-guards.pl -vn.

Cleaned up with scripts/clean-header-guards.pl, followed by some
renaming of new guard symbols picked by the script to better ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:19:16 +02:00
Markus Armbruster a9c94277f0 Use #include "..." for our own headers, <...> for others
Tracked down with an ugly, brittle and probably buggy Perl script.

Also move includes converted to <...> up so they get included before
ours where that's obviously okay.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:19:16 +02:00
Sergey Sorokin b35399bb4e Fix confusing argument names in some common functions
There are functions tlb_fill(), cpu_unaligned_access() and
do_unaligned_access() that are called with access type and mmu index
arguments. But these arguments are named 'is_write' and 'is_user' in their
declarations. The patches fix the arguments to avoid a confusion.

Signed-off-by: Sergey Sorokin <afarallax@yandex.ru>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-id: 1465907177-1399402-1-git-send-email-afarallax@yandex.ru
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-07-12 13:06:08 +01:00
Sergey Sorokin 1f00b27f17 tcg: Improve the alignment check infrastructure
Some architectures (e.g. ARMv8) need the address which is aligned
to a size more than the size of the memory access.
To support such check it's enough the current costless alignment
check implementation in QEMU, but we need to support
an alignment size specifying.

Signed-off-by: Sergey Sorokin <afarallax@yandex.ru>
Message-Id: <1466705806-679898-1-git-send-email-afarallax@yandex.ru>
Signed-off-by: Richard Henderson <rth@twiddle.net>
[rth: Assert in tcg_canonicalize_memop.  Leave get_alignment_bits
available for, though unused by, user-mode.  Retain logging difference
based on ALIGNED_ONLY.]
2016-07-05 20:50:13 -07:00
Peter Maydell 39e0b03dec memory: Assert that memory_region_init_rom_device() ops aren't NULL
It doesn't make sense to pass a NULL ops argument to
memory_region_init_rom_device(), because the effect will
be that if the guest tries to write to the memory region
then QEMU will segfault. Catch the bug earlier by sanity
checking the arguments to this function, and remove the
misleading documentation that suggests that passing NULL
might be sensible.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1467122287-24974-4-git-send-email-peter.maydell@linaro.org
2016-07-04 13:06:35 +01:00
Peter Maydell a1777f7f64 memory: Provide memory_region_init_rom()
Provide a new helper function memory_region_init_rom() for memory
regions which are read-only (and unlike those created by
memory_region_init_rom_device() don't have special behaviour
for writes). This has the same behaviour as calling
memory_region_init_ram() and then memory_region_set_readonly()
(which is what we do today in boards with pure ROMs) but is a
more easily discoverable API for the purpose.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1467122287-24974-2-git-send-email-peter.maydell@linaro.org
2016-07-04 13:06:35 +01:00
Alexey Kardashevskiy d22d8956b1 memory: Add MemoryRegionIOMMUOps.notify_started/stopped callbacks
The IOMMU driver may change behavior depending on whether a notifier
client is present.  In the case of POWER, this represents a change in
the visibility of the IOTLB, for other drivers such as intel-iommu and
future AMD-Vi emulation, notifier support is not yet enabled and this
provides the opportunity to flag that incompatibility.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Peter Xu <peterx@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
[new log & extracted from [PATCH qemu v17 12/12] spapr_iommu, vfio, memory: Notify IOMMU about starting/stopping listening]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-06-30 13:00:23 -06:00
Peter Crosthwaite 8642c1b81e target-*: Don't redefine cpu_exec()
This function needs to be converted to QOM hook and virtualised for
multi-arch. This rename interferes, as cpu-qom will not have access
to the renaming causing name divergence. This rename doesn't really do
anything anyway so just delete it.

Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-Id: <69bd25a8678b8b31b91cd9760c777bed1aafb44e.1437212383.git.crosthwaite.peter@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Crosthwaite <crosthwaitepeter@gmail.com>
2016-06-29 14:03:47 +02:00
Alexey Kardashevskiy f682e9c244 memory: Add reporting of supported page sizes
Every IOMMU has some granularity which MemoryRegionIOMMUOps::translate
uses when translating, however this information is not available outside
the translate context for various checks.

This adds a get_min_page_size callback to MemoryRegionIOMMUOps and
a wrapper for it so IOMMU users (such as VFIO) can know the minimum
actual page size supported by an IOMMU.

As IOMMU MR represents a guest IOMMU, this uses TARGET_PAGE_SIZE
as fallback.

This removes vfio_container_granularity() and uses new helper in
memory_region_iommu_replay() when replaying IOMMU mappings on added
IOMMU memory region.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
[dwg: Removed an unnecessary calculation]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2016-06-22 11:13:09 +10:00
Lluís Vilanova dcdaadb6ea trace: [all] Add "guest_mem_before" event
The event is described in "trace-events". Note that the "MO_AMASK" flag
is not traced, since it does not seem to affect the visible semantics of
instructions.

[s/inline inline/inline/ to fix clang build.
--Stefan]

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 146549350711.18437.726780393247474362.stgit@fimbulvetr.bsc.es
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-20 17:21:56 +01:00
Emilio G. Cota 909eaac9bb tb hash: track translated blocks with qht
Having a fixed-size hash table for keeping track of all translation blocks
is suboptimal: some workloads are just too big or too small to get maximum
performance from the hash table. The MRU promotion policy helps improve
performance when the hash table is a little undersized, but it cannot
make up for severely undersized hash tables.

Furthermore, frequent MRU promotions result in writes that are a scalability
bottleneck. For scalability, lookups should only perform reads, not writes.
This is not a big deal for now, but it will become one once MTTCG matures.

The appended fixes these issues by using qht as the implementation of
the TB hash table. This solution is superior to other alternatives considered,
namely:

- master: implementation in QEMU before this patchset
- xxhash: before this patch, i.e. fixed buckets + xxhash hashing + MRU.
- xxhash-rcu: fixed buckets + xxhash + RCU list + MRU.
              MRU is implemented here by adding an intermediate struct
              that contains the u32 hash and a pointer to the TB; this
              allows us, on an MRU promotion, to copy said struct (that is not
              at the head), and put this new copy at the head. After a grace
              period, the original non-head struct can be eliminated, and
              after another grace period, freed.
- qht-fixed-nomru: fixed buckets + xxhash + qht without auto-resize +
                   no MRU for lookups; MRU for inserts.
The appended solution is the following:
- qht-dyn-nomru: dynamic number of buckets + xxhash + qht w/ auto-resize +
                 no MRU for lookups; MRU for inserts.

The plots below compare the considered solutions. The Y axis shows the
boot time (in seconds) of a debian jessie image with arm-softmmu; the X axis
sweeps the number of buckets (or initial number of buckets for qht-autoresize).
The plots in PNG format (and with errorbars) can be seen here:
  http://imgur.com/a/Awgnq

Each test runs 5 times, and the entire QEMU process is pinned to a
single core for repeatability of results.

                            Host: Intel Xeon E5-2690

  28 ++------------+-------------+-------------+-------------+------------++
     A*****        +             +             +             master **A*** +
  27 ++    *                                                 xxhash ##B###++
     |      A******A******                               xxhash-rcu $$C$$$ |
  26 C$$                  A******A******            qht-fixed-nomru*%%D%%%++
     D%%$$                              A******A******A*qht-dyn-mru A*E****A
  25 ++ %%$$                                          qht-dyn-nomru &&F&&&++
     B#####%                                                               |
  24 ++    #C$$$$$                                                        ++
     |      B###  $                                                        |
     |          ## C$$$$$$                                                 |
  23 ++           #       C$$$$$$                                         ++
     |             B######       C$$$$$$                                %%%D
  22 ++                  %B######       C$$$$$$C$$$$$$C$$$$$$C$$$$$$C$$$$$$C
     |                    D%%%%%%B######      @E@@@@@@    %%%D%%%@@@E@@@@@@E
  21 E@@@@@@E@@@@@@F&&&@@@E@@@&&&D%%%%%%B######B######B######B######B######B
     +             E@@@   F&&&   +      E@     +      F&&&   +             +
  20 ++------------+-------------+-------------+-------------+------------++
     14            16            18            20            22            24
                             log2 number of buckets

                                 Host: Intel i7-4790K

  14.5 ++------------+------------+-------------+------------+------------++
       A**           +            +             +            master **A*** +
    14 ++ **                                                 xxhash ##B###++
  13.5 ++   **                                           xxhash-rcu $$C$$$++
       |                                            qht-fixed-nomru %%D%%% |
    13 ++     A******                                   qht-dyn-mru @@E@@@++
       |             A*****A******A******             qht-dyn-nomru &&F&&& |
  12.5 C$$                               A******A******A*****A******    ***A
    12 ++ $$                                                        A***  ++
       D%%% $$                                                             |
  11.5 ++  %%                                                             ++
       B###  %C$$$$$$                                                      |
    11 ++  ## D%%%%% C$$$$$                                               ++
       |     #      %      C$$$$$$                                         |
  10.5 F&&&&&&B######D%%%%%       C$$$$$$C$$$$$$C$$$$$$C$$$$$C$$$$$$    $$$C
    10 E@@@@@@E@@@@@@B#####B######B######E@@@@@@E@@@%%%D%%%%%D%%%###B######B
       +             F&&          D%%%%%%B######B######B#####B###@@@D%%%   +
   9.5 ++------------+------------+-------------+------------+------------++
       14            16           18            20           22            24
                              log2 number of buckets

Note that the original point before this patch series is X=15 for "master";
the little sensitivity to the increased number of buckets is due to the
poor hashing function in master.

xxhash-rcu has significant overhead due to the constant churn of allocating
and deallocating intermediate structs for implementing MRU. An alternative
would be do consider failed lookups as "maybe not there", and then
acquire the external lock (tb_lock in this case) to really confirm that
there was indeed a failed lookup. This, however, would not be enough
to implement dynamic resizing--this is more complex: see
"Resizable, Scalable, Concurrent Hash Tables via Relativistic
Programming" by Triplett, McKenney and Walpole. This solution was
discarded due to the very coarse RCU read critical sections that we have
in MTTCG; resizing requires waiting for readers after every pointer update,
and resizes require many pointer updates, so this would quickly become
prohibitive.

qht-fixed-nomru shows that MRU promotion is advisable for undersized
hash tables.

However, qht-dyn-mru shows that MRU promotion is not important if the
hash table is properly sized: there is virtually no difference in
performance between qht-dyn-nomru and qht-dyn-mru.

Before this patch, we're at X=15 on "xxhash"; after this patch, we're at
X=15 @ qht-dyn-nomru. This patch thus matches the best performance that we
can achieve with optimum sizing of the hash table, while keeping the hash
table scalable for readers.

The improvement we get before and after this patch for booting debian jessie
with arm-softmmu is:

- Intel Xeon E5-2690: 10.5% less time
- Intel i7-4790K: 5.2% less time

We could get this same improvement _for this particular workload_ by
statically increasing the size of the hash table. But this would hurt
workloads that do not need a large hash table. The dynamic (upward)
resizing allows us to start small and enlarge the hash table as needed.

A quick note on downsizing: the table is resized back to 2**15 buckets
on every tb_flush; this makes sense because it is not guaranteed that the
table will reach the same number of TBs later on (e.g. most bootup code is
thrown away after boot); it makes sense to grow the hash table as
more code blocks are translated. This also avoids the complication of
having to build downsizing hysteresis logic into qht.

Reviewed-by: Sergey Fedorov <serge.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-15-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11 17:11:16 -07:00
Emilio G. Cota 42bd32287f tb hash: hash phys_pc, pc, and flags with xxhash
For some workloads such as arm bootup, tb_phys_hash is performance-critical.
The is due to the high frequency of accesses to the hash table, originated
by (frequent) TLB flushes that wipe out the cpu-private tb_jmp_cache's.
More info:
  https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg05098.html

To dig further into this I modified an arm image booting debian jessie to
immediately shut down after boot. Analysis revealed that quite a bit of time
is unnecessarily spent in tb_phys_hash: the cause is poor hashing that
results in very uneven loading of chains in the hash table's buckets;
the longest observed chain had ~550 elements.

The appended addresses this with two changes:

1) Use xxhash as the hash table's hash function. xxhash is a fast,
   high-quality hashing function.

2) Feed the hashing function with not just tb_phys, but also pc and flags.

This improves performance over using just tb_phys for hashing, since that
resulted in some hash buckets having many TB's, while others getting very few;
with these changes, the longest observed chain on a single hash bucket is
brought down from ~550 to ~40.

Tests show that the other element checked for in tb_find_physical,
cs_base, is always a match when tb_phys+pc+flags are a match,
so hashing cs_base is wasteful. It could be that this is an ARM-only
thing, though. UPDATE:
On Tue, Apr 05, 2016 at 08:41:43 -0700, Richard Henderson wrote:
> The cs_base field is only used by i386 (in 16-bit modes), and sparc (for a TB
> consisting of only a delay slot).
> It may well still turn out to be reasonable to ignore cs_base for hashing.

BTW, after this change the hash table should not be called "tb_hash_phys"
anymore; this is addressed later in this series.

This change gives consistent bootup time improvements. I tested two
host machines:
- Intel Xeon E5-2690: 11.6% less time
- Intel i7-4790K: 19.2% less time

Increasing the number of hash buckets yields further improvements. However,
using a larger, fixed number of buckets can degrade performance for other
workloads that do not translate as many blocks (600K+ for debian-jessie arm
bootup). This is dealt with later in this series.

Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-8-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11 23:10:19 +00:00
Emilio G. Cota dc8b295d05 exec: add tb_hash_func5, derived from xxhash
This will be used by upcoming changes for hashing the tb hash.

Add this into a separate file to include the copyright notice from
xxhash.

Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-7-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-11 23:10:18 +00:00
Peter Maydell 6886b98036 cpu-exec: Rename cpu_resume_from_signal() to cpu_loop_exit_noexc()
The function cpu_resume_from_signal() is now always called with a
NULL puc argument, and is rather misnamed since it is never called
from a signal handler. It is essentially forcing an exit to the
top level cpu loop but without raising any exception, so rename
it to cpu_loop_exit_noexc() and drop the useless unused argument.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Message-id: 1463494687-25947-4-git-send-email-peter.maydell@linaro.org
2016-06-09 15:55:02 +01:00
Peter Maydell b66e10e4c9 linux-user pull request for June 2016
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Merge remote-tracking branch 'remotes/riku/tags/pull-linux-user-20160608' into staging

linux-user pull request for June 2016

# gpg: Signature made Wed 08 Jun 2016 14:27:14 BST
# gpg:                using RSA key 0xB44890DEDE3C9BC0
# gpg: Good signature from "Riku Voipio <riku.voipio@iki.fi>"
# gpg:                 aka "Riku Voipio <riku.voipio@linaro.org>"

* remotes/riku/tags/pull-linux-user-20160608: (44 commits)
  linux-user: In fork_end(), remove correct CPUs from CPU list
  linux-user: Special-case ERESTARTSYS in target_strerror()
  linux-user: Make target_strerror() return 'const char *'
  linux-user: Correct signedness of target_flock l_start and l_len fields
  linux-user: Use safe_syscall wrapper for ioctl
  linux-user: Use safe_syscall wrapper for accept and accept4 syscalls
  linux-user: Use safe_syscall wrapper for semop
  linux-user: Use safe_syscall wrapper for epoll_wait syscalls
  linux-user: Use safe_syscall wrapper for poll and ppoll syscalls
  linux-user: Use safe_syscall wrapper for sleep syscalls
  linux-user: Use safe_syscall wrapper for rt_sigtimedwait syscall
  linux-user: Use safe_syscall wrapper for flock
  linux-user: Use safe_syscall wrapper for mq_timedsend and mq_timedreceive
  linux-user: Use safe_syscall wrapper for msgsnd and msgrcv
  linux-user: Use safe_syscall wrapper for send* and recv* syscalls
  linux-user: Use safe_syscall wrapper for connect syscall
  linux-user: Use safe_syscall wrapper for readv and writev syscalls
  linux-user: Fix error conversion in 64-bit fadvise syscall
  linux-user: Fix NR_fadvise64 and NR_fadvise64_64 for 32-bit guests
  linux-user: Fix handling of arm_fadvise64_64 syscall
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Conflicts:
	configure
	scripts/qemu-binfmt-conf.sh
2016-06-08 18:34:32 +01:00
Peter Maydell e0ca2ed562 thunk: Rename args and fields in host-target bitmask conversion code
The target_to_host_bitmask() and host_to_target_bitmask() functions
and the associated struct bitmask_transtbl are completely generic,
but for historical reasons the target related fields and parameters
are named 'x86' and the host related fields are named 'alpha'.
Rename them to 'target' and 'host'.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-06-07 18:19:24 +03:00
Peter Maydell 7a00217d1a thunk: Drop unused NO_THUNK_TYPE_SIZE guards
The thunk_type_size_array() and thunk_type_align_array() functions
are only provided if NO_THUNK_TYPE_SIZE is not defined. However
nothing in the codebase defines that, and so in fact these functions
are always present. Drop the unnecessary #ifdefs.

(Over a decade ago thunk.h used to be included by some softmmu
files, which defined NO_THUNK_TYPE_SIZE, but these includes are
long gone; see for instance commit f193c7979c2f7.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-06-07 18:19:24 +03:00
Peter Maydell 0d5c21f2b3 qemu-common.h: Drop WORDS_ALIGNED define
The WORDS_ALIGNED #define is not used anywhere, and hasn't been since
2013 when commit 612d590ebc rewrote the various ld<type>_<endian>_p
functions to not use it. Remove the #define and the comment describing it.
Also remove the line in the comment about TARGET_WORDS_ALIGNED, since
it has never actually existed.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-06-07 18:19:24 +03:00
Peter Maydell 24a6e0633a hw: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-06-07 18:19:23 +03:00
Timothy E Baldwin 8fdb9fef3d linux-user: Remove redundant gdb_queuesig()
Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-22-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-07 16:39:07 +03:00
Paolo Bonzini 0878d0e11b exec: hide mr->ram_addr from qemu_get_ram_ptr users
Let users of qemu_get_ram_ptr and qemu_ram_ptr_length pass in an
address that is relative to the MemoryRegion.  This basically means
what address_space_translate returns.

Because the semantics of the second parameter change, rename the
function to qemu_map_ram_ptr.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29 09:11:12 +02:00
Paolo Bonzini 07bdaa4196 memory: split memory_region_from_host from qemu_ram_addr_from_host
Move the old qemu_ram_addr_from_host to memory_region_from_host and
make it return an offset within the region.  For qemu_ram_addr_from_host
return the ram_addr_t directly, similar to what it was before
commit 1b5ec23 ("memory: return MemoryRegion from qemu_ram_addr_from_host",
2013-07-04).

Reviewed-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29 09:11:12 +02:00
Paolo Bonzini f615f39616 exec: remove ram_addr argument from qemu_ram_block_from_host
Of the two callers, one does not use it, and the other can compute
it itself based on the other output argument (offset) and the RAMBlock.

Reviewed-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29 09:11:12 +02:00
Paolo Bonzini 4ff87573df memory: remove qemu_get_ram_fd, qemu_set_ram_fd, qemu_ram_block_host_ptr
Remove direct uses of ram_addr_t and optimize memory_region_{get,set}_fd
now that a MemoryRegion knows its RAMBlock directly.

Reviewed-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-29 09:11:12 +02:00
Fam Zheng b613597819 memory: Remove code for mr->may_overlap
The collision check does nothing and hasn't been used. Remove the
variable together with related code.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1458900629-2334-2-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-23 16:53:44 +02:00
Gonglei fa53a0e53e memory: drop find_ram_block()
On the one hand, we have already qemu_get_ram_block() whose function
is similar. On the other hand, we can directly use mr->ram_block but
searching RAMblock by ram_addr which is a kind of waste.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <1462845901-89716-2-git-send-email-arei.gonglei@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-23 16:53:44 +02:00
Paolo Bonzini df43d49cb8 hw: clean up hw/hw.h includes
Include qom/object.h and exec/memory.h instead of exec/ioport.h;
exec/ioport.h was almost everywhere required only for those two
includes, not for the content of the header itself.

Remove block/aio.h, everybody is already including it through
another path.

With this change, include/hw/hw.h is freed from qemu-common.h.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:30 +02:00
Paolo Bonzini 89a80e7400 hw: remove pio_addr_t
pio_addr_t is almost unused, because these days I/O ports are simply
accessed through the address space.  cpu_{in,out}[bwl] themselves are
almost unused; monitor.c and xen-hvm.c could use address_space_read/write
directly, since they have an integer size at hand.  This leaves qtest as
the only user of those functions.

On the other hand even portio_* functions use this type; the only
interesting use of pio_addr_t thus is include/hw/sysbus.h.  I guess I
could move it there, but I don't see much benefit in that either.  Using
uint32_t is enough and avoids the need to include ioport.h everywhere.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:30 +02:00
Paolo Bonzini 63c915526d cpu: move exec-all.h inclusion out of cpu.h
exec-all.h contains TCG-specific definitions.  It is not needed outside
TCG-specific files such as translate.c, exec.c or *helper.c.

One generic function had snuck into include/exec/exec-all.h; move it to
include/qom/cpu.h.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:29 +02:00
Paolo Bonzini 00f6da6a1a exec: extract exec/tb-context.h
TCG backends do not need most of exec-all.h; extract what they actually
need to a separate file or move it directly to tcg.h.  The next patch
will stop including exec-all.h from everywhere.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:29 +02:00
Paolo Bonzini 33c11879fd qemu-common: push cpu.h inclusion out of qemu-common.h
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:29 +02:00