On 2025-08-05 03:59, Jan Beulich wrote:
While it is correct that in shim-exclusive mode log-dirty handling is
all unreachable code, the present conditional still isn't correct: In a
HVM=n and SHADOW_PAGING=n configuration log-dirty code also is all
unreachable (and hence violating Misra rule 2.1).
As we're aiming at moving away from special casing PV_SHIM_EXCLUSIVE=y,
don't retain that part of the conditional.
Because of hypercall-defs.c we need to carry out the dependency by
introducing a new auxiliary PAGING control.
Since compiling out mm/paging.c altogether would entail further changes,
merely conditionalize the one function in there (paging_enable()) which
would otherwise remain unreachable (Misra rule 2.1 again) when PAGING=n.
Fixes: 23d4e0d17b76 ("x86/shim: fix build with PV_SHIM_EXCLUSIVE and
SHADOW_PAGING")
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
Of course PAGING is at risk of being confused with MEM_PAGING. It not
having a prompt, I hope that's tolerable, as I can't really think of a
better name.
Other PG_log_dirty pre-processor conditionals then likely also want
replacing. mm/paging.c and mm/p2m-basic.c could also be compiled out
altogether when PAGING=n, at the expense of introducing a few more
stubs.
FTAOD, the Fixes: tag being referenced does not mean this patch corrects
the far more recently introduced build issue with the combination of the
two features. That's still work that I expect Penny to carry out (with
there still being the option of reverting the final part of the earlier
series).
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -864,6 +864,7 @@ void paging_final_teardown(struct domain
p2m_final_teardown(d);
}
+#ifdef CONFIG_PAGING
The file already has a lot of uses of #if PG_log_dirty with similar
meaning, if I am not mistaken, so using that would make it more
consistent. But CONFIG_PAGING is directly tied to the Kconfig, so maybe
it is better? Just something I noticed.
Reviewed-by: Jason Andryuk <jason.andr...@amd.com>
Regards,
Jason
/* Enable an arbitrary paging-assistance mode. Call once at domain
* creation. */
int paging_enable(struct domain *d, u32 mode)
@@ -889,6 +890,7 @@ int paging_enable(struct domain *d, u32
else
return shadow_enable(d, mode);
}
+#endif
#ifdef CONFIG_HVM
/* Called from the guest to indicate that a process is being torn down
