Currently, we configure QEMU to prealloc memory almost by
default. Well, by default for NVDIMMs, hugepages and if user
asked us to (via memoryBacking <allocation mode="immediate"/>).
However, when guest's NVDIMM is backed by real life NVDIMM this
approach is not the best. In this case users should put <pmem/>
into the <memory/> device <source/>, like this:
<memory model='nvdimm' access='shared'>
<source>
<path>/dev/pmem0</path>
<pmem/>
</source>
</memory>
Instructing QEMU to do prealloc in this case means that each
page of the NVDIMM is "touched" (the first byte is read and
written back - see QEMU commit v2.9.0-rc1~26^2) which cripples
device wear.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1894053
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
In 88957116c9 I've switched to -machine memory-backend=ID and
-object memory-backend-* because QEMU is obsoleting -mem-path
and -mem-prealloc. However, what I did not foresee was that using
-machine memory-backend in combination with -numa is not allowed
in QEMU. This was reported upstream and fortunately not released
yet.
The problem is that if domain has NUMA nodes then we will
generate memory-backend-* objects for NUMA nodes (because if QEMU
is new enough to expose default RAM ID it also supports -numa
memdev=) and adding non-NUMA memory backend is wrong.
Reported-by: Masayoshi Mizuma <msys.mizuma@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
So far, Libvirt configures memory-backend-* for memory hotplug,
possibly NUMA nodes and in a few other cases. This patch
switches to constructing the memory-backend-* command line for
all cases. To keep ability to migrate guests a little hack is
used: the ID of the object is set to the one that QEMU uses
internally anyways. These IDs are stable (first started to appear
somewhere around v0.13.0-rc0~96) and can't change.
In fact, this patch does exactly what QEMU does internally. The
reason for moving the logic into Libvirt is that QEMU wants to
deprecate the old style of specifying memory.
So far, only x84_64 test cases are changed, because tests for
other architectures use older capabilities, which still lack the
QEMU_CAPS_MACHINE_MEMORY_BACKEND capability and they don't report
the RAM ID.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1836043
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
All three memory backends (-file, -ram and -memfd) have .prealloc
attribute. Since we are setting it only for -file, the
corresponding code lives only under if() that handles that
specific backend. But in near future we will want to set the
attribute for other backends too. Therefore, move the
corresponding code outside of the if().
This causes some .argv files to be changed, but the only change
happening there is move of the attribute (best viewed with:
'git show --color-words=.').
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Note that 'numa-mem-supported' turned off for certain machine types
which in turn forced us to generate a newer command line in certain
tests.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Commit 82576d8f35 used a string "on" to enable the 'pmem' property.
This is okay for the command line visitor, but the property is declared
as boolean in qemu and thus it will not work when using QMP.
Modify the type to boolean. This changes the command line, but
fortunately the command line visitor in qemu parses both 'yes' and 'on'
as true for the property.
https://bugzilla.redhat.com/show_bug.cgi?id=1854684
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The previous approac of just purging the alias combined with the fact
that we filled in fake machine types in the test data meant that if a
test case used an alias machine type such as 'pc' or 'q35' it would not
properly resolve to the actual data returned by qemu.
This started to be a problem since the CPU driver now looks at the
default CPU reported with the machine type.
This patch replaces the original approach of just removing the alias by
replacing it with a copy of the machine type data which the type would
alias to. This means that we are using the real data while we don't
modify the test output after every qemu upgrade.
Additionally this change will allow us to drop adding the fake machine
types later.
The test fallout is from actually excercising the CPU driver with
actual data.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
QEMU since 4.1.0 supports the "dies" parameter for -smp
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The 32-bit x86 binary is called qemu-system-i386, not
qemu-system-i686. This mistake across many test XML files was
not noticed because the mistake was also made in testutilsqemu.c
when mocking the capabilities.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Now that all pieces are in place (hopefully) let's enable -blockdev.
We base the capability on presence of the fix for 'auto-read-only' on
files so that blockdev works properly, mandate that qemu supports
explicit SCSI id strings to avoid ABI regression and that the fix for
'savevm' is present so that internal snapshots work.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The latter is deprecated and will be removed soon. The advised
replacement is '-overcommit mem-lock=on|off'.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
By default, qemu user's home dir points to '/' which shouldn't be used
at all. We therefore pass the HOME variable from the current variable
iff not running as SUID, which means that for systemd we never set it.
This patch makes sure, that for system QEMU this is always set to
libDir/<driver>, session mode is left untouched.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
For session mode, only XDG_CACHE_HOME is set, because we want to remain
integrating with services in user session, but for system mode, this
would have become reading/writing to '/' which carries the obvious issue
with permissions (also, '/' is the wrong location in 99.9% cases anyway).
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
According to the result parsing from xml, add pmem property
into QEMU command line:
-object memory-backend-file,...[,pmem=on]
Signed-off-by: Luyao Zhong <luyao.zhong@intel.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
