Commit Graph
255 Commits
Author SHA1 Message Date
David HildenbrandandJuan Quintela adaf9d92f8 memory: Introduce replay_discarded callback for RamDiscardManager
Introduce replay_discarded callback similar to our existing
replay_populated callback, to be used my migration code to never migrate
discarded memory.

Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2021-11-01 22:56:44 +01:00
Hyman Huang(黄勇)andJuan Quintela 63b41db4bc memory: make global_dirty_tracking a bitmask
since dirty ring has been introduced, there are two methods
to track dirty pages of vm. it seems that "logging" has
a hint on the method, so rename the global_dirty_log to
global_dirty_tracking would make description more accurate.

dirty rate measurement may start or stop dirty tracking during
calculation. this conflict with migration because stop dirty
tracking make migration leave dirty pages out then that'll be
a problem.

make global_dirty_tracking a bitmask can let both migration and
dirty rate measurement work fine. introduce GLOBAL_DIRTY_MIGRATION
and GLOBAL_DIRTY_DIRTY_RATE to distinguish what current dirty
tracking aims for, migration or dirty rate.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Message-Id: <9c9388657cfa0301bd2c1cfa36e7cf6da4aeca19.1624040308.git.huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2021-11-01 22:56:43 +01:00
Peter XuandPaolo Bonzini 142518bda5 memory: Name all the memory listeners
Provide a name field for all the memory listeners.  It can be used to identify
which memory listener is which.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210817013553.30584-2-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-30 15:30:24 +02:00
Sean ChristophersonandPaolo Bonzini 56918a126a memory: Add RAM_PROTECTED flag to skip IOMMU mappings
Add a new RAMBlock flag to denote "protected" memory, i.e. memory that
looks and acts like RAM but is inaccessible via normal mechanisms,
including DMA.  Use the flag to skip protected memory regions when
mapping RAM for DMA in VFIO.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-30 14:50:19 +02:00
David HildenbrandandEduardo Habkost 7e6d32ebf7 softmmu/physmem: Extend ram_block_discard_(require|disable) by two discard types
We want to separate the two cases whereby we discard ram
- uncoordinated: e.g., virito-balloon
- coordinated: e.g., virtio-mem coordinated via the RamDiscardManager

Reviewed-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210413095531.25603-12-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2021-07-08 15:54:45 -04:00
David HildenbrandandEduardo Habkost 228438384e memory: Helpers to copy/free a MemoryRegionSection
In case one wants to create a permanent copy of a MemoryRegionSections,
one needs access to flatview_ref()/flatview_unref(). Instead of exposing
these, let's just add helpers to copy/free a MemoryRegionSection and
properly adjust references.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210413095531.25603-3-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2021-07-08 15:54:45 -04:00
David HildenbrandandEduardo Habkost 8947d7fc4e memory: Introduce RamDiscardManager for RAM memory regions
We have some special RAM memory regions (managed by virtio-mem), whereby
the guest agreed to only use selected memory ranges. "unused" parts are
discarded so they won't consume memory - to logically unplug these memory
ranges. Before the VM is allowed to use such logically unplugged memory
again, coordination with the hypervisor is required.

This results in "sparse" mmaps/RAMBlocks/memory regions, whereby only
coordinated parts are valid to be used/accessed by the VM.

In most cases, we don't care about that - e.g., in KVM, we simply have a
single KVM memory slot. However, in case of vfio, registering the
whole region with the kernel results in all pages getting pinned, and
therefore an unexpected high memory consumption - discarding of RAM in
that context is broken.

Let's introduce a way to coordinate discarding/populating memory within a
RAM memory region with such special consumers of RAM memory regions: they
can register as listeners and get updates on memory getting discarded and
populated. Using this machinery, vfio will be able to map only the
currently populated parts, resulting in discarded parts not getting pinned
and not consuming memory.

A RamDiscardManager has to be set for a memory region before it is getting
mapped, and cannot change while the memory region is mapped.

Note: At some point, we might want to let RAMBlock users (esp. vfio used
for nvme://) consume this interface as well. We'll need RAMBlock notifier
calls when a RAMBlock is getting mapped/unmapped (via the corresponding
memory region), so we can properly register a listener there as well.

Reviewed-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210413095531.25603-2-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2021-07-08 15:54:37 -04:00
David HildenbrandandPaolo Bonzini 8dbe22c686 memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()
Let's introduce RAM_NORESERVE, allowing mmap'ing with MAP_NORESERVE. The
new flag has the following semantics:

"
RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge
pages if applicable) is skipped: will bail out if not supported. When not
set, the OS will do the reservation, if supported for the memory type.
"

Allow passing it into:
- memory_region_init_ram_nomigrate()
- memory_region_init_resizeable_ram()
- memory_region_init_ram_from_file()

... and teach qemu_ram_mmap() and qemu_anon_ram_alloc() about the flag.
Bail out if the flag is not supported, which is the case right now for
both, POSIX and win32. We will add Linux support next and allow specifying
RAM_NORESERVE via memory backends.

The target use case is virtio-mem, which dynamically exposes memory
inside a large, sparse memory area to the VM.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-9-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-15 20:27:38 +02:00
David HildenbrandandPaolo Bonzini 7f863cba4d softmmu/memory: Pass ram_flags to memory_region_init_ram_shared_nomigrate()
Let's forward ram_flags instead, renaming
memory_region_init_ram_shared_nomigrate() into
memory_region_init_ram_flags_nomigrate().

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-6-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-15 20:27:38 +02:00
David HildenbrandandPaolo Bonzini d5015b8013 softmmu/memory: Pass ram_flags to qemu_ram_alloc_from_fd()
Let's pass in ram flags just like we do with qemu_ram_alloc_from_file(),
to clean up and prepare for more flags.

Simplify the documentation of passed ram flags: Looking at our
documentation of RAM_SHARED and RAM_PMEM is sufficient, no need to be
repetitive.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com> for memory backend and machine core
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210510114328.21835-5-david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-06-15 20:27:38 +02:00
John SnowandLaurent Vivier d7878875ae docs: fix broken reference
Long story short, we need a space here for the reference to work
correctly.

Longer story:

Without the space, kerneldoc generates a line like this:

one of :c:type:`MemoryListener.region_add\(\) <MemoryListener>`,:c:type:`MemoryListener.region_del\(\)

Sphinx does not process the role information correctly, so we get this
(my pseudo-notation) construct:

<text>,:c:type:</text>
<reference target="MemoryListener">MemoryListener.region_del()</reference>

which does not reference the desired entity, and leaves some extra junk
in the rendered output. See
https://qemu-project.gitlab.io/qemu/devel/memory.html#c.MemoryListener
member log_start for an example of the broken output as it looks today.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20210511192950.2061326-1-jsnow@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-06-05 21:15:22 +02:00
Peter Maydell 62c0ac5041 Merge remote-tracking branch 'remotes/rth-gitlab/tags/pull-tcg-20210526' into staging
Adjust types for some memory access functions.
Reduce inclusion of tcg headers.
Fix watchpoints vs replay.
Fix tcg/aarch64 roli expansion.
Introduce SysemuCPUOps structure.

# gpg: Signature made Thu 27 May 2021 00:43:54 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth-gitlab/tags/pull-tcg-20210526: (31 commits)
  hw/core: Constify TCGCPUOps
  target/mips: Fold jazz behaviour into mips_cpu_do_transaction_failed
  cpu: Move CPUClass::get_paging_enabled to SysemuCPUOps
  cpu: Move CPUClass::get_memory_mapping to SysemuCPUOps
  cpu: Move CPUClass::get_phys_page_debug to SysemuCPUOps
  cpu: Move CPUClass::asidx_from_attrs to SysemuCPUOps
  cpu: Move CPUClass::write_elf* to SysemuCPUOps
  cpu: Move CPUClass::get_crash_info to SysemuCPUOps
  cpu: Move CPUClass::virtio_is_big_endian to SysemuCPUOps
  cpu: Move CPUClass::vmsd to SysemuCPUOps
  cpu: Introduce SysemuCPUOps structure
  cpu: Move AVR target vmsd field from CPUClass to DeviceClass
  cpu: Rename CPUClass vmsd -> legacy_vmsd
  cpu: Assert DeviceClass::vmsd is NULL on user emulation
  cpu: Directly use get_memory_mapping() fallback handlers in place
  cpu: Directly use get_paging_enabled() fallback handlers in place
  cpu: Directly use cpu_write_elf*() fallback handlers in place
  cpu: Introduce cpu_virtio_is_big_endian()
  cpu: Un-inline cpu_get_phys_page_debug and cpu_asidx_from_attrs
  cpu: Split as cpu-common / cpu-sysemu
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-05-28 16:25:21 +01:00
Philippe Mathieu-DaudéandRichard Henderson 4121f4b38e exec/memory: Use correct type size
Use uint8_t for (unsigned) byte.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210518183655.1711377-7-philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-05-26 08:35:51 -07:00
Peter XuandPaolo Bonzini b87eaa9b82 memory: Introduce log_sync_global() to memory listener
Some of the memory listener may want to do log synchronization without
being able to specify a range of memory to sync but always globally.
Such a memory listener should provide this new method instead of the
log_sync() method.

Obviously we can also achieve similar thing when we put the global
sync logic into a log_sync() handler. However that's not efficient
enough because otherwise memory_global_dirty_log_sync() may do the
global sync N times, where N is the number of flat ranges in the
address space.

Make this new method be exclusive to log_sync().

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210506160549.130416-2-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-05-26 14:49:45 +02:00
David HildenbrandandDr. David Alan Gilbert c7c0e72408 migration/ram: Handle RAM block resizes during precopy
Resizing while migrating is dangerous and does not work as expected.
The whole migration code works on the usable_length of ram blocks and does
not expect this to change at random points in time.

In the case of precopy, the ram block size must not change on the source,
after syncing the RAM block list in ram_save_setup(), so as long as the
guest is still running on the source.

Resizing can be trigger *after* (but not during) a reset in
ACPI code by the guest
- hw/arm/virt-acpi-build.c:acpi_ram_update()
- hw/i386/acpi-build.c:acpi_ram_update()

Use the ram block notifier to get notified about resizes. Let's simply
cancel migration and indicate the reason. We'll continue running on the
source. No harm done.

Update the documentation. Postcopy will be handled separately.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210429112708.12291-5-david@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Manual merge
2021-05-13 18:21:13 +01:00
Peter Maydell b3566001d4 memory: Add offset_in_region to flatview_cb arguments
The function flatview_for_each_range() calls a callback for each
range in a FlatView.  Currently the callback gets the start and
length of the range and the MemoryRegion involved, but not the offset
within the MemoryRegion.  Add this to the callback's arguments; we're
going to want it for a new use in the next commit.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210318174823.18066-4-peter.maydell@linaro.org
2021-03-23 11:47:31 +00:00
Peter Maydell a5e32ec1ed memory: Document flatview_for_each_range()
Add a documentation comment describing flatview_for_each_range().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210318174823.18066-3-peter.maydell@linaro.org
2021-03-23 11:47:31 +00:00
Peter Maydell d1e8cf77f1 memory: Make flatview_cb return bool, not int
The return value of the flatview_cb callback passed to the
flatview_for_each_range() function is zero if the iteration through
the ranges should continue, or non-zero to break out of it.  Use a
bool for this rather than int.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210318174823.18066-2-peter.maydell@linaro.org
2021-03-23 11:47:31 +00:00
Markus Armbruster bb3c92ed10 memory: Drop "qemu:" prefix from QOM memory region type names
Almost all QOM type names consist only of letters, digits, '-', '_',
and '.'.  Just two contain ':': "qemu:memory-region" and
"qemu:iommu-memory-region".  Neither can be plugged with -object.
Rename them to "memory-region" and "iommu-memory-region".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210304140229.575481-3-armbru@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-19 15:18:43 +01:00
Philippe Mathieu-DaudéandLaurent Vivier d32335e8ed exec/memory: Use struct Object typedef
We forward-declare Object typedef in "qemu/typedefs.h" since commit
ca27b5eb7c ("qom/object: Move Object typedef to 'qemu/typedefs.h'").
Use it everywhere to make the code simpler.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210225182003.3629342-1-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-03-09 21:53:57 +01:00
Jagannathan RamanandStefan Hajnoczi 44a4ff31c0 memory: alloc RAM from file at offset
Allow RAM MemoryRegion to be created from an offset in a file, instead
of allocating at offset of 0 by default. This is needed to synchronize
RAM between QEMU & remote process.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 609996697ad8617e3b01df38accc5c208c24d74e.1611938319.git.jag.raman@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-02-09 20:53:56 +00:00
Peter Maydell 41d306ec7d Merge remote-tracking branch 'remotes/bonzini-gitlab/tags/for-upstream' into staging
* Fuzzing improvements (Qiuhao, Alexander)
* i386: Fix BMI decoding for instructions with the 0x66 prefix (David)
* initial attempt at fixing event_notifier emulation (Maxim)
* i386: PKS emulation, fix for "qemu-system-i386 -cpu host" (myself)
* meson: RBD test fixes (myself)
* meson: TCI warnings (Philippe)
* Leaner build for --disable-guest-agent, --disable-system and
  --disable-tools (Philippe, Stefan)
* --enable-tcg-interpreter fix (Richard)
* i386: SVM feature bits (Wei)
* KVM bugfix (Thomas H.)
* Add missing MemoryRegionOps callbacks (PJP)

# gpg: Signature made Mon 08 Feb 2021 14:15:35 GMT
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini-gitlab/tags/for-upstream: (46 commits)
  target/i386: Expose VMX entry/exit load pkrs control bits
  target/i386: Add support for save/load IA32_PKRS MSR
  imx7-ccm: add digprog mmio write method
  tz-ppc: add dummy read/write methods
  spapr_pci: add spapr msi read method
  nvram: add nrf51_soc flash read method
  prep: add ppc-parity write method
  vfio: add quirk device write method
  pci-host: designware: add pcie-msi read method
  hw/pci-host: add pci-intack write method
  cpu-throttle: Remove timer_mod() from cpu_throttle_set()
  replay: rng-builtin support
  pc-bios/descriptors: fix paths in json files
  replay: fix replay of the interrupts
  accel/kvm/kvm-all: Fix wrong return code handling in dirty log code
  qapi/meson: Restrict UI module to system emulation and tools
  qapi/meson: Restrict system-mode specific modules
  qapi/meson: Remove QMP from user-mode emulation
  qapi/meson: Restrict qdev code to system-mode emulation
  meson: Restrict emulation code
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-02-09 10:04:51 +00:00
Alexander BulekovandPaolo Bonzini fc1c8344e6 fuzz: ignore address_space_map is_write flag
We passed an is_write flag to the fuzz_dma_read_cb function to
differentiate between the mapped DMA regions that need to be populated
with fuzzed data, and those that don't. We simply passed through the
address_space_map is_write parameter. The goal was to cut down on
unnecessarily populating mapped DMA regions, when they are not read
from.

Unfortunately, nothing precludes code from reading from regions mapped
with is_write=true. For example, see:
https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg04729.html

This patch removes the is_write parameter to fuzz_dma_read_cb. As a
result, we will fill all mapped DMA regions with fuzzed data, ignoring
the specified transfer direction.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210120060255.558535-1-alxndr@bu.edu>
2021-02-08 14:43:54 +01:00
Andrey GruzdevandDr. David Alan Gilbert 278e2f551a migration: support UFFD write fault processing in ram_save_iterate()
In this particular implementation the same single migration
thread is responsible for both normal linear dirty page
migration and procesing UFFD page fault events.

Processing write faults includes reading UFFD file descriptor,
finding respective RAM block and saving faulting page to
the migration stream. After page has been saved, write protection
can be removed. Since asynchronous version of qemu_put_buffer()
is expected to be used to save pages, we also have to flush
migraion stream prior to un-protecting saved memory range.

Write protection is being removed for any previously protected
memory chunk that has hit the migration stream. That's valid
for pages from linear page scan along with write fault pages.

Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20210129101407.103458-4-andrey.gruzdev@virtuozzo.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  fixup pagefault.address cast for 32bit
2021-02-08 11:19:51 +00:00
Andrey GruzdevandDr. David Alan Gilbert 0e9b5cd6b2 migration: introduce UFFD-WP low-level interface helpers
Glue code to the userfaultfd kernel implementation.
Querying feature support, createing file descriptor, feature control,
memory region registration, IOCTLs on registered registered regions.

Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210129101407.103458-3-andrey.gruzdev@virtuozzo.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Fixed up range.start casting for 32bit
2021-02-08 11:19:51 +00:00