Re: [PATCH v2 4/5] tests/qtest: Rework nvmetest_oob_cmb_test for BAR check

[Peter Maydell <peter.maydell@linaro.org>]

On Thu, 27 Nov 2025 at 00:13, Navid Emamdoost <navidem@google.com> wrote:
>
> The nvmetest_oob_cmb_test was designed to deliberately perform an
> out-of-bounds write on a PCI BAR. This was intended as a regression
> test for CVE-2018-16847.
> The recent change to libqos introduced strict bounds checking on all
> BAR accessors, which correctly caused this test to fail with a fatal
> assertion, as it was performing an illegal memory access.
> This change reworks the test to honor its original intent—verifying
> safe accesses at the BAR boundary—without violating the new API contract.
> Instead of attempting an illegal write, the test now performs several
> valid read/write operations at the very end of the BAR (at offsets
> size - 1, size - 2, and size - 4) to confirm the entire region
> is accessible.
> This makes the test compatible with the safer libqos API while still
> serving as a regression test for the original issue.

This one I'll have to leave for the nvme folks to review.
(You'll want to recast the commit message because this
change has to go before we add the assertions, not after.)

thanks
-- PMM