Re: [PATCH v2 0/3] Change default pointer authentication algorithm on aarch64 to impdef

[Peter Maydell]

On Fri, 10 Jan 2025 at 16:28, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Thu, 19 Dec 2024 at 18:32, Pierrick Bouvier
> <pierrick.bouvier@linaro.org> wrote:
> >
> > qemu-system-aarch64 default pointer authentication (QARMA5) is expensive, we
> > spent up to 50% of the emulation time running it (when using TCG).
> >
> > Switching to pauth-impdef=on is often given as a solution to speed up 
> > execution.
> > Thus we talked about making it the new default.
> >
> > The first patch introduce a new property (pauth-qarma5) to allow to select
> > current default algorithm.
> > The second one change the default.
> > The third one updates documentation.
> >
> > v2:
> > - ensure we don't break migration compatibility, by using a specific 
> > backward
> >   compatible property.
> > - added some documentation about migration for arm virt machine model.
>
> Other than a minor change to the 3rd docs patch which I'll note there:
> applied to target-arm.next, thanks.

I just noticed that this series breaks 'make check-tcg', because
the pauth-3 test is explicitly checking the output of the
pointer-auth operation. I'm going to add in this patch, which
goes between patches 1 and 2 of this series:

Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Mon Jan 13 11:42:57 2025 +0000

    tests/tcg/aarch64: force qarma5 for pauth-3 test

    The pauth-3 test explicitly tests that a computation of the
    pointer-authentication produces the expected result.  This means that
    it must be run with the QARMA5 algorithm.

    Explicitly set the pauth algorithm when running this test, so that it
    doesn't break when we change the default algorithm the 'max' CPU
    uses.

    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/tests/tcg/aarch64/Makefile.softmmu-target
b/tests/tcg/aarch64/Makefile.softmmu-target
index d08d9b01ded..9c52475b7ae 100644
--- a/tests/tcg/aarch64/Makefile.softmmu-target
+++ b/tests/tcg/aarch64/Makefile.softmmu-target
@@ -91,6 +91,9 @@ EXTRA_RUNS+=run-memory-replay

 ifneq ($(CROSS_CC_HAS_ARMV8_3),)
 pauth-3: CFLAGS += $(CROSS_CC_HAS_ARMV8_3)
+# This test explicitly checks the output of the pauth operation so we
+# must force the use of the QARMA5 algorithm for it.
+run-pauth-3: QEMU_BASE_MACHINE=-M virt -cpu max,pauth-qarma5=on -display none
 else
 pauth-3:
        $(call skip-test, "BUILD of $@", "missing compiler support")


thanks
-- PMM