Commit Graph

10 Commits

Author SHA1 Message Date
Paolo Bonzini
04502fd54f util: introduce virHostCPUGetMicrocodeVersion
This new API reads host's CPU microcode version from /proc/cpuinfo.

Unfortunately, there is no other way of reading microcode version which
would be usable from both system and session daemon.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2018-01-04 16:52:03 +01:00
Daniel P. Berrange
407a281a8e Revert "Prevent more compiler optimization of mockable functions"
This reverts commit e4b980c853.

When a binary links against a .a archive (as opposed to a shared library),
any symbols which are marked as 'weak' get silently dropped. As a result
when the binary later runs, those 'weak' functions have an address of
0x0 and thus crash when run.

This happened with virtlogd and virtlockd because they don't link to
libvirt.so, but instead just libvirt_util.a and libvirt_rpc.a. The
virRandomBits symbols was weak and so left out of the virtlogd &
virtlockd binaries, despite being required by virHashTable functions.

Various other binaries like libvirt_lxc, libvirt_iohelper, etc also
link directly to .a files instead of libvirt.so, so are potentially
at risk of dropping symbols leading to a later runtime crash.

This is normal linker behaviour because a weak symbol is not treated
as undefined, so nothing forces it to be pulled in from the .a You
have to force the linker to pull in weak symbols using -u$SYMNAME
which is not a practical approach.

This risk is silent bad linkage that affects runtime behaviour is
not acceptable for a fix that was merely trying to fix the test
suite. So stop using __weak__ again.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-07-13 13:07:06 +01:00
Daniel P. Berrange
e4b980c853 Prevent more compiler optimization of mockable functions
Currently all mockable functions are annotated with the 'noinline'
attribute. This is insufficient to guarantee that a function can
be reliably mocked with an LD_PRELOAD. The C language spec allows
the compiler to assume there is only a single implementation of
each function. It can thus do things like propagating constant
return values into the caller at compile time, or creating
multiple specialized copies of the function body each optimized
for a different caller. To prevent these optimizations we must
also set the 'noclone' and 'weak' attributes.

This fixes the test suite when libvirt.so is built with CLang
with optimization enabled.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-07-11 13:57:12 +01:00
Daniel P. Berrange
728cacc8ab annotate all mocked functions with noinline
CLang's optimizer is more aggressive at inlining functions than
gcc and so will often inline functions that our tests want to
mock-override. This causes the test to fail in bizarre ways.

We don't want to disable inlining completely, but we must at
least prevent inlining of mocked functions. Fortunately there
is a 'noinline' attribute that lets us control this per function.

A syntax check rule is added that parses tests/*mock.c to extract
the list of functions that are mocked (restricted to names starting
with 'vir' prefix). It then checks that src/*.h header file to
ensure it has a 'ATTRIBUTE_NOINLINE' annotation. This should prevent
use from bit-rotting in future.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-04-19 10:51:51 +01:00
Martin Kletzander
71732f0f54 virhostcpu: Make only defined symbols available
That way you get the error from the compiler before the linker.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2017-03-27 17:34:59 +02:00
Martin Kletzander
c67e04e25f util: Adapt virhostcpu to the new virsysfs
While on that, drop support for kernels from RHEL-5 era (missing
cpu/present file).  Also add some useful functions and export them.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2017-03-27 13:13:29 +02:00
Viktor Mihajlovski
1be35910f7 util: Allow to query the presence of host CPU bitmaps
The functions to retrieve online and present host CPU information
are only supported on Linux for the time being.

This leads to runtime errors if these function are used on other
platforms. To avoid that, code in higher levels using the functions
must replicate the conditional compilation in higher level which
is error prone (and is plainly spoken ugly).

Adding a function virHostCPUHasBitmap that can be used to check
for host CPU bitmap support.

NB: There are other functions including the host CPU count that
are lacking support on all platforms, but they are too essential
in order to be bypassed.

Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
2016-12-13 18:12:09 -05:00
Tomáš Ryšavý
63f388c99d virhostcpu: Expose virHostCPUStatsAssign
We will need this function shortly when implementing
nodeGetCPUStats in the test driver.

Signed-off-by: Tomáš Ryšavý <tom.rysavy.0@gmail.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2016-09-15 15:28:22 +02:00
Shivaprasad G Bhat
b95965c4f8 Rename kvmGetMaxVCPUs() to virHostCPUGetKVMMaxVCPUs()
This kvmGetMaxVCPUs() needs to be used at two different places
so move it to utils with appropriate name and mark it as private
global now.

Signed-off-by: Shivaprasad G Bhat <sbhat@linux.vnet.ibm.com>
2016-06-24 18:52:21 +02:00
Daniel P. Berrange
eaf18f4c2b nodeinfo: move host CPU APIs out into virhostcpu.c file
Move all APIs with a virHostCPU name prefix out into new
util/virhostcpu.h & util/virhostcpu.c files

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2016-06-09 18:31:11 +01:00