This patch contains test which minimally tests write-zeroes on top of
working discard.
The following checks are added:
* write 2 clusters, write-zero to the first allocated cluster
* write 2 cluster, write-zero to the half the first allocated cluster
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
The zero flag is missed in the Parallels format specification. We can
resort to discard if we have no backing file.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
This patch contains test which minimally tests discard and new cluster
allocation logic.
The following checks are added:
* write 2 clusters, discard the first allocated
* write another cluster, check that the hole is filled
* write 2 clusters, discard the first allocated, write 1 cluster at
non-aligned to cluster offset (2 new clusters should be allocated)
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
* Discarding with backing stores is not supported by the format.
* There is no buffering/queueing of the discard operation.
* Only operations aligned to the cluster are supported.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Replace 'space' representing the amount of data to preallocate with
'bytes'.
Rationale:
* 'space' at each place is converted to bytes
* the unit is more close to the variable name
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
The access to the bitmap is not optimized completely.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
We should extend the bitmap if the file is extended and set the bit in
the image used bitmap once the cluster is allocated. Sanity check at
that moment also looks like a good idea.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
This would be useful in the next patch in allocate_clusters(). This
change would not imply serious performance drawbacks as usually image
is full of data or are at the end of the bitmap.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
The test is quite similar with the original one for duplicated clusters.
There is the only difference in the operation which should fix the
image.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Original check is broken as supposed reading from 2 different clusters
results in read from the same file offset twice. This is definitely
wrong.
We should be sure that
* the content of both clusters is correct after repair
* clusters are at the different offsets after repair
In order to check the latter we write some content into the first one
and validate that fact.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
If the operation is failed, we need to check image consistency if the
problem is not about memory allocation.
Bitmap adjustments in allocate_cluster are not performed yet.
They worth to be separate. This was proven useful during debug of this
series. Kept as is for future bissecting.
It should be specifically noted that used bitmap must be recalculated
if data_off has been fixed during image consistency check.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
We have only check through self-repair and that proven to be not enough.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Once we have repaired data_off field in the header we should update
s->data_start which is calculated on the base of it.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Since
commit cfce1091d5
Author: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Date: Tue Jul 18 12:44:29 2023 +0200
parallels: Image repairing in parallels_open()
there is a potential pit fall with calling
qemu-io -c "read"
The image is opened in read-write mode and thus could be potentially
repaired. This could ruin testing process.
The patch forces read-only opening for reads. In that case repairing
is impossible.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
This functionality is used twice already and next patch will add more
code with it.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
More conditions follows thus the check should be more scalable.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
At the beginning of the function we can return immediately until we
really allocate s->header.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
We do not need to perform any deallocation/cleanup if wrong format is
detected.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
This patch creates above mentioned helper and moves its usage to the
beginning of parallels_open(). This simplifies parallels_open() a bit.
The patch also ensures that we store prealloc_size on block driver state
always in sectors. This makes code cleaner and avoids wrong opinion at
the assignment that the value is in bytes.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
We should free opts allocated through qemu_opts_create() at the end.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Parallels driver indeed support Parallels Dirty Bitmap Feature in
read-only mode. The patch adds bdrv_supports_persistent_dirty_bitmap()
callback which always return 1 to indicate that.
This will allow to copy CBT from Parallels image with qemu-img.
Note: read-write support is signalled through
bdrv_co_can_store_new_dirty_bitmap() and is different.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Old code is ugly and contains tabulations. There are no functional
changes in this patch.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
"Host Memory Backends" and "Memory devices" queue ("mem"):
- Support and document VM templating with R/O files using a new "rom"
parameter for memory-backend-file
- Some cleanups and fixes around NVDIMMs and R/O file handling for guest
RAM
- Optimize ioeventfd updates by skipping address spaces that are not
applicable
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Merge tag 'mem-2023-09-19' of https://github.com/davidhildenbrand/qemu into staging
Hi,
"Host Memory Backends" and "Memory devices" queue ("mem"):
- Support and document VM templating with R/O files using a new "rom"
parameter for memory-backend-file
- Some cleanups and fixes around NVDIMMs and R/O file handling for guest
RAM
- Optimize ioeventfd updates by skipping address spaces that are not
applicable
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# gpg: Signature made Tue 19 Sep 2023 06:25:45 EDT
# gpg: using RSA key 1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A
# gpg: issuer "david@redhat.com"
# gpg: Good signature from "David Hildenbrand <david@redhat.com>" [unknown]
# gpg: aka "David Hildenbrand <davidhildenbrand@gmail.com>" [full]
# gpg: aka "David Hildenbrand <hildenbr@in.tum.de>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 1BD9 CAAD 735C 4C3A 460D FCCA 4DDE 10F7 00FF 835A
* tag 'mem-2023-09-19' of https://github.com/davidhildenbrand/qemu:
memory: avoid updating ioeventfds for some address_space
machine: Improve error message when using default RAM backend id
softmmu/physmem: Hint that "readonly=on,rom=off" exists when opening file R/W for private mapping fails
docs: Start documenting VM templating
docs: Don't mention "-mem-path" in multi-process.rst
softmmu/physmem: Never return directories from file_ram_open()
softmmu/physmem: Fail creation of new files in file_ram_open() with readonly=true
softmmu/physmem: Bail out early in ram_block_discard_range() with readonly files
softmmu/physmem: Remap with proper protection in qemu_ram_remap()
backends/hostmem-file: Add "rom" property to support VM templating with R/O files
softmmu/physmem: Distinguish between file access mode and mmap protection
nvdimm: Reject writing label data to ROM instead of crashing QEMU
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
In this short queue we're making two important changes:
- Nicholas Piggin is now the qemu-ppc maintainer. Cédric Le Goater and
Daniel Barboza will act as backup during Nick's transition to this new
role.
- Support for NVIDIA V100 GPU with NVLink2 is dropped from qemu-ppc.
Linux removed the same support back in 5.13, we're following suit now.
A xive Coverity fix is also included.
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Merge tag 'pull-ppc-20230918' of https://gitlab.com/danielhb/qemu into staging
ppc patch queue for 2023-09-18:
In this short queue we're making two important changes:
- Nicholas Piggin is now the qemu-ppc maintainer. Cédric Le Goater and
Daniel Barboza will act as backup during Nick's transition to this new
role.
- Support for NVIDIA V100 GPU with NVLink2 is dropped from qemu-ppc.
Linux removed the same support back in 5.13, we're following suit now.
A xive Coverity fix is also included.
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# gpg: Signature made Mon 18 Sep 2023 09:24:44 EDT
# gpg: using EDDSA key 17EBFF9923D01800AF2838193CD9CA96DE033164
# gpg: issuer "danielhb413@gmail.com"
# gpg: Good signature from "Daniel Henrique Barboza <danielhb413@gmail.com>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 17EB FF99 23D0 1800 AF28 3819 3CD9 CA96 DE03 3164
* tag 'pull-ppc-20230918' of https://gitlab.com/danielhb/qemu:
spapr: Remove support for NVIDIA V100 GPU with NVLink2
ppc/xive: Fix uint32_t overflow
MAINTAINERS: Nick Piggin PPC maintainer, other PPC changes
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When updating ioeventfds, we need to iterate all address spaces,
but some address spaces do not register eventfd_add|del call when
memory_listener_register() and they do nothing when updating ioeventfds.
So we can skip these AS in address_space_update_ioeventfds().
The overhead of memory_region_transaction_commit() can be significantly
reduced. For example, a VM with 8 vhost net devices and each one has
64 vectors, can reduce the time spent on memory_region_transaction_commit by 20%.
Message-ID: <20230830032906.12488-1-hongmianquan@bytedance.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: hongmianquan <hongmianquan@bytedance.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
For migration purposes, users might want to reuse the default RAM
backend id, but specify a different memory backend.
For example, to reuse "pc.ram" on q35, one has to set
-machine q35,memory-backend=pc.ram
Only then, can a memory backend with the id "pc.ram" be created
manually.
Let's improve the error message by improving the hint. Use
error_append_hint() -- which in turn requires ERRP_GUARD().
Message-ID: <20230906120503.359863-12-david@redhat.com>
Suggested-by: ThinerLogoer <logoerthiner1@163.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
It's easy to miss that memory-backend-file with "share=off" (default)
will always try opening the file R/W as default, and fail if we don't
have write permissions to the file.
In that case, the user has to explicit specify "readonly=on,rom=off" to
get usable RAM, for example, for VM templating.
Let's hint that '-object memory-backend-file,readonly=on,rom=off,...'
exists to consume R/O files in a private mapping to create writable RAM,
but only if we have permissions to open the file read-only.
Message-ID: <20230906120503.359863-11-david@redhat.com>
Suggested-by: ThinerLogoer <logoerthiner1@163.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's add some details about VM templating, focusing on the VM memory
configuration only.
There is much more to VM templating (VM state? block devices?), but I leave
that as future work.
Message-ID: <20230906120503.359863-10-david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
"-mem-path" corresponds to "memory-backend-file,share=off" and,
therefore, creates a private COW mapping of the file. For multi-proces
QEMU, we need proper shared file-backed memory.
Let's make that clearer.
Message-ID: <20230906120503.359863-9-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
open() does not fail on directories when opening them readonly (O_RDONLY).
Currently, we succeed opening such directories and fail later during
mmap(), resulting in a misleading error message.
$ ./qemu-system-x86_64 \
-object memory-backend-file,id=ram0,mem-path=tmp,readonly=true,size=1g
qemu-system-x86_64: unable to map backing store for guest RAM: No such device
To identify directories and handle them accordingly in file_ram_open()
also when readonly=true was specified, detect if we just opened a directory
using fstat() instead. Then, fail file_ram_open() right away, similarly
to how we now fail if the file does not exist and we want to open the
file readonly.
With this change, we get a nicer error message:
qemu-system-x86_64: can't open backing store tmp for guest RAM: Is a directory
Note that the only memory-backend-file will end up calling
memory_region_init_ram_from_file() -> qemu_ram_alloc_from_file() ->
file_ram_open().
Message-ID: <20230906120503.359863-8-david@redhat.com>
Reported-by: Thiner Logoer <logoerthiner1@163.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Currently, if a file does not exist yet, file_ram_open() will create new
empty file and open it writable. However, it even does that when
readonly=true was specified.
Specifying O_RDONLY instead to create a new readonly file would
theoretically work, however, ftruncate() will refuse to resize the new
empty file and we'll get a warning:
ftruncate: Invalid argument
And later eventually more problems when actually mmap'ing that file and
accessing it.
If someone intends to let QEMU open+mmap a file read-only, better
create+resize+fill that file ahead of time outside of QEMU context.
We'll now fail with:
./qemu-system-x86_64 \
-object memory-backend-file,id=ram0,mem-path=tmp,readonly=true,size=1g
qemu-system-x86_64: can't open backing store tmp for guest RAM: No such file or directory
All use cases of readonly files (R/O NVDIMMs, VM templating) work on
existing files, so silently creating new files might just hide user
errors when accidentally specifying a non-existent file.
Note that the only memory-backend-file will end up calling
memory_region_init_ram_from_file() -> qemu_ram_alloc_from_file() ->
file_ram_open().
Move error reporting to the single caller.
Message-ID: <20230906120503.359863-7-david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
fallocate() will fail, let's print a nicer error message.
Message-ID: <20230906120503.359863-6-david@redhat.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's remap with the proper protection that we can derive from
RAM_READONLY.
Message-ID: <20230906120503.359863-5-david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
For now, "share=off,readonly=on" would always result in us opening the
file R/O and mmap'ing the opened file MAP_PRIVATE R/O -- effectively
turning it into ROM.
Especially for VM templating, "share=off" is a common use case. However,
that use case is impossible with files that lack write permissions,
because "share=off,readonly=on" will not give us writable RAM.
The sole user of ROM via memory-backend-file are R/O NVDIMMs, but as we
have users (Kata Containers) that rely on the existing behavior --
malicious VMs should not be able to consume COW memory for R/O NVDIMMs --
we cannot change the semantics of "share=off,readonly=on"
So let's add a new "rom" property with on/off/auto values. "auto" is
the default and what most people will use: for historical reasons, to not
change the old semantics, it defaults to the value of the "readonly"
property.
For VM templating, one can now use:
-object memory-backend-file,share=off,readonly=on,rom=off,...
But we'll disallow:
-object memory-backend-file,share=on,readonly=on,rom=off,...
because we would otherwise get an error when trying to mmap the R/O file
shared and writable. An explicit error message is cleaner.
We will also disallow for now:
-object memory-backend-file,share=off,readonly=off,rom=on,...
-object memory-backend-file,share=on,readonly=off,rom=on,...
It's not harmful, but also not really required for now.
Alternatives that were abandoned:
* Make "unarmed=on" for the NVDIMM set the memory region container
readonly. We would still see a change of ROM->RAM and possibly run
into memslot limits with vhost-user. Further, there might be use cases
for "unarmed=on" that should still allow writing to that memory
(temporary files, system RAM, ...).
* Add a new "readonly=on/off/auto" parameter for NVDIMMs. Similar issues
as with "unarmed=on".
* Make "readonly" consume "on/off/file" instead of being a 'bool' type.
This would slightly changes the behavior of the "readonly" parameter:
values like true/false (as accepted by a 'bool'type) would no longer be
accepted.
Message-ID: <20230906120503.359863-4-david@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
There is a difference between how we open a file and how we mmap it,
and we want to support writable private mappings of readonly files. Let's
define RAM_READONLY and RAM_READONLY_FD flags, to replace the single
"readonly" parameter for file-related functions.
In memory_region_init_ram_from_fd() and memory_region_init_ram_from_file(),
initialize mr->readonly based on the new RAM_READONLY flag.
While at it, add some RAM_* flags we missed to add to the list of accepted
flags in the documentation of some functions.
No change in functionality intended. We'll make use of both flags next
and start setting them independently for memory-backend-file.
Message-ID: <20230906120503.359863-3-david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Currently, when using a true R/O NVDIMM (ROM memory backend) with a label
area, the VM can easily crash QEMU by trying to write to the label area,
because the ROM memory is mmap'ed without PROT_WRITE.
[root@vm-0 ~]# ndctl disable-region region0
disabled 1 region
[root@vm-0 ~]# ndctl zero-labels nmem0
-> QEMU segfaults
Let's remember whether we have a ROM memory backend and properly
reject the write request:
[root@vm-0 ~]# ndctl disable-region region0
disabled 1 region
[root@vm-0 ~]# ndctl zero-labels nmem0
zeroed 0 nmem
In comparison, on a system with a R/W NVDIMM:
[root@vm-0 ~]# ndctl disable-region region0
disabled 1 region
[root@vm-0 ~]# ndctl zero-labels nmem0
zeroed 1 nmem
For ACPI, just return "unsupported", like if no label exists. For spapr,
return "H_P2", similar to when no label area exists.
Could we rely on the "unarmed" property? Maybe, but it looks cleaner to
only disallow what certainly cannot work.
After all "unarmed=on" primarily means: cannot accept persistent writes. In
theory, there might be setups where devices with "unarmed=on" set could
be used to host non-persistent data (temporary files, system RAM, ...); for
example, in Linux, admins can overwrite the "readonly" setting and still
write to the device -- which will work as long as we're not using ROM.
Allowing writing label data in such configurations can make sense.
Message-ID: <20230906120503.359863-2-david@redhat.com>
Fixes: dbd730e859 ("nvdimm: check -object memory-backend-file, readonly=on option")
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
NVLink2 support was removed from the PPC PowerNV platform and VFIO in
Linux 5.13 with commits :
562d1e207d32 ("powerpc/powernv: remove the nvlink support")
b392a1989170 ("vfio/pci: remove vfio_pci_nvlink2")
This was 2.5 years ago. Do the same in QEMU with a revert of commit
ec132efaa8 ("spapr: Support NVIDIA V100 GPU with NVLink2"). Some
adjustements are required on the NUMA part.
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Message-ID: <20230918091717.149950-1-clg@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
As reported by Coverity, "idx << xive->pc_shift" is evaluated using
32-bit arithmetic, and then used in a context expecting a "uint64_t".
Add a uint64_t cast.
Fixes: Coverity CID 1519049
Fixes: b68147b7a5 ("ppc/xive: Add support for the PC MMIOs")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Message-ID: <20230914154650.222111-1-clg@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Denis V. Lunev