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Re: [Xen-devel] [PATCH] VMX: fix vmx_{find,del}_msr() build

>>> On 16.07.18 at 18:56, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 16/07/18 17:46, Jan Beulich wrote:
>> For a reason that I can't explain, it is only the shim build that fails
>> for me with an older gcc due to the compiler not recognizing that
>> apparently uninitialized variables aren't really uninitialized.
> The only thing that comes to mind is some differences in CFLAGS et al. 
> There is nothing in kconfig which would plausibly impact that code.

Indeed - I was under the wrong impression that one of my configs
on that box had CONFIG_DEBUG=n, but that was wrong. Switching
the supposed config back into that mode makes the issue surface in
a non-shim build as well. The difference is -O1 vs -O2; the latter
allows the compiler to kind of see "deeper" through expressions. So
I think the patch should be considered as is, perhaps with the extra
question whether to make vmx_add_msr() match the two changed
functions, even if the problem doesn't surface there (presumably
due to the "return" in the initial switch statement).


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