Re: [Qemu-devel] [PATCH v3] accel: forbid early use of kvm_enabled() and friends

[Stefan Hajnoczi]

On Thu, Jul 05, 2018 at 09:54:30AM +0200, Greg Kurz wrote:
> It is unsafe to rely on *_enabled() helpers before the accelerator has
> been initialized, ie, accel_init_machine() has succeeded, because they
> always return false. But it is still possible to end up calling them
> indirectly by inadvertance, and cause QEMU to misbehave.
> 
> This patch causes QEMU to abort if we try to check for any accelerator
> before accel_init_machine() was called. This will help to catch bugs
> earlier.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
> 
> Current master (SHA1 2a018f6e9878) has such a kvm_enabled() misuse that
> triggers the assert:
> 
> https://travis-ci.org/gkurz/qemu/jobs/400059821#L8709
> 
> The fix for the misuse is available, waiting to be merged:
> 
> https://patchwork.ozlabs.org/patch/938077/
> 
> v3: - use an inline function
>     - convert all accelerators
>     - dropped David's R-b
> 
> v2: - dropped change in qom/cpu.c (useless header inclusion)
>     - only #include "sysemu/kvm.h" if we actually need it
>     - added David's R-b from v1 because changes in v2 are minor
> ---
>  accel/accel.c             |    4 ++++
>  include/hw/xen/xen.h      |    3 ++-
>  include/qemu-common.h     |    3 ++-
>  include/sysemu/accel.h    |    8 ++++++++
>  include/sysemu/hvf.h      |    3 ++-
>  include/sysemu/kvm.h      |    3 ++-
>  include/sysemu/qtest.h    |    3 ++-
>  stubs/Makefile.objs       |    1 +
>  stubs/accel.c             |   12 ++++++++++++
>  target/i386/hax-all.c     |    2 +-
>  target/i386/whpx-all.c    |    2 +-
>  tests/ptimer-test-stubs.c |    2 ++
>  12 files changed, 39 insertions(+), 7 deletions(-)
>  create mode 100644 stubs/accel.c

Reviewed-by: Stefan Hajnoczi <address@hidden>

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