[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH] Revert "cputlb: Restrict SavedIOTLB to system emulation"
From: |
Peter Maydell |
Subject: |
[PATCH] Revert "cputlb: Restrict SavedIOTLB to system emulation" |
Date: |
Tue, 20 Jun 2023 18:57:12 +0100 |
This reverts commit d7ee93e24359703debf4137f4cc632563aa4e8d1.
That commit tries to make a field in the CPUState struct not be
present when CONFIG_USER_ONLY is set. Unfortunately, you can't
conditionally omit fields in structs like this based on ifdefs that
are set per-target. If you try it, then code in files compiled
per-target (where CONFIG_USER_ONLY is or can be set) will disagree
about the struct layout with files that are compiled once-only (where
this kind of ifdef is never set).
This manifests specifically in 'make check-tcg' failing, because code
in cpus-common.c that sets up the CPUState::cpu_index field puts it
at a different offset from the code in plugins/core.c in
qemu_plugin_vcpu_init_hook() which reads the cpu_index field. The
latter then hits an assert because from its point of view every
thread has a 0 cpu_index. There might be other weird behaviour too.
Mostly we catch this kind of bug because the CONFIG_whatever is
listed in include/exec/poison.h and so the reference to it in
build-once source files will then cause a compiler error.
Unfortunately CONFIG_USER_ONLY is an exception to that: we have some
places where we use it in "safe" ways in headers that will be seen by
once-only source files (e.g. ifdeffing out function prototypes) and
it would be a lot of refactoring to be able to get to a position
where we could poison it. This leaves us in a "you have to be
careful to walk around the bear trap" situation...
Fixes: d7ee93e243597 ("cputlb: Restrict SavedIOTLB to system emulation")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
include/hw/core/cpu.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index ee8d6b40b3b..4871ad85f07 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -226,7 +226,7 @@ struct CPUWatchpoint {
QTAILQ_ENTRY(CPUWatchpoint) entry;
};
-#if defined(CONFIG_PLUGIN) && !defined(CONFIG_USER_ONLY)
+#ifdef CONFIG_PLUGIN
/*
* For plugins we sometime need to save the resolved iotlb data before
* the memory regions get moved around by io_writex.
@@ -410,11 +410,9 @@ struct CPUState {
#ifdef CONFIG_PLUGIN
GArray *plugin_mem_cbs;
-#if !defined(CONFIG_USER_ONLY)
/* saved iotlb data from io_writex */
SavedIOTLB saved_iotlb;
-#endif /* !CONFIG_USER_ONLY */
-#endif /* CONFIG_PLUGIN */
+#endif
/* TODO Move common fields from CPUArchState here. */
int cpu_index;
--
2.34.1
- [PATCH] Revert "cputlb: Restrict SavedIOTLB to system emulation",
Peter Maydell <=