On 19/4/25 03:09, Pierrick Bouvier wrote:
On 4/18/25 10:29, Philippe Mathieu-Daudé wrote:
Add a helper to distinct the binary is targetting
Aarch64 or not.
Start with a dump strcmp() implementation, leaving
room for future optimizations.
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
include/qemu/target_info.h | 7 +++++++
target_info.c | 5 +++++
2 files changed, 12 insertions(+)
diff --git a/include/qemu/target_info.h b/include/qemu/target_info.h
index c67b97d66f3..9b7575ce632 100644
--- a/include/qemu/target_info.h
+++ b/include/qemu/target_info.h
@@ -24,4 +24,11 @@ const char *target_name(void);
*/
const char *target_machine_typename(void);
+/**
+ * target_aarch64:
+ *
+ * Returns whether the target architecture is Aarch64.
+ */
+bool target_aarch64(void);
+
#endif
diff --git a/target_info.c b/target_info.c
index 1de4334ecc5..87dd1d51778 100644
--- a/target_info.c
+++ b/target_info.c
@@ -19,3 +19,8 @@ const char *target_machine_typename(void)
{
return target_info()->machine_typename;
}
+
+bool target_aarch64(void)
+{
+ return !strcmp(target_name(), "aarch64");
I don't think doing strcmp is a good move here, even temporarily.
A short term solution is making target_info.c target specific, and use:
return TARGET_AARCH64;
IIUC as
https://lore.kernel.org/qemu-devel/20231122183048.17150-3-phi...@linaro.org/?
The long term solution, is to have a create target_current() that
returns an enum, and target_aarch64() would become:
return target_current() == {ENUM}_AARCH64. We just need to find a good
name for {enum} which is not Target, since it's a poisoned identifier.
This way, we can easily convert the simple
#ifdef TARGET_AARCH64 by if target_aarch64(),
and more complicated combinations by a switch on target_current().
This was
https://lore.kernel.org/qemu-devel/20250403234914.9154-4-phi...@linaro.org/,
which was useful for the virtio-mem patch:
-- >8 --
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index c7968ee0c61..b5d62411b3e 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -17,2 +17,3 @@
#include "qemu/units.h"
+#include "qemu/target_info.h"
#include "system/numa.h"
@@ -35,9 +36,17 @@ static const VMStateDescription
vmstate_virtio_mem_device_early;
-/*
- * We only had legacy x86 guests that did not support
- * VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE. Other targets don't have legacy
guests.
- */
-#if defined(TARGET_X86_64) || defined(TARGET_I386)
-#define VIRTIO_MEM_HAS_LEGACY_GUESTS
-#endif
+static bool virtio_mem_has_legacy_guests(void)
+{
+ /*
+ * We only had legacy x86 guests that did not support
+ * VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE. Other targets don't have
+ * legacy guests.
+ */
+ switch (target_system_arch()) {
+ case SYS_EMU_TARGET_I386:
+ case SYS_EMU_TARGET_X86_64:
+ return true;
+ default:
+ return false;
+ }
+}
@@ -145,3 +154,2 @@ static uint64_t
virtio_mem_default_block_size(RAMBlock *rb)
-#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
static bool virtio_mem_has_shared_zeropage(RAMBlock *rb)
@@ -156,3 +164,2 @@ static bool virtio_mem_has_shared_zeropage(RAMBlock *rb)
}
-#endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
@@ -999,24 +1006,26 @@ static void virtio_mem_device_realize(DeviceState
*dev, Error **errp)
-#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
- switch (vmem->unplugged_inaccessible) {
- case ON_OFF_AUTO_AUTO:
- if (virtio_mem_has_shared_zeropage(rb)) {
- vmem->unplugged_inaccessible = ON_OFF_AUTO_OFF;
- } else {
- vmem->unplugged_inaccessible = ON_OFF_AUTO_ON;
+ if (virtio_mem_has_legacy_guests()) {
+ switch (vmem->unplugged_inaccessible) {
+ case ON_OFF_AUTO_AUTO:
+ if (virtio_mem_has_shared_zeropage(rb)) {
+ vmem->unplugged_inaccessible = ON_OFF_AUTO_OFF;
+ } else {
+ vmem->unplugged_inaccessible = ON_OFF_AUTO_ON;
+ }
+ break;
+ case ON_OFF_AUTO_OFF:
+ if (!virtio_mem_has_shared_zeropage(rb)) {
+ warn_report("'%s' property set to 'off' with a memdev
that does"
+ " not support the shared zeropage.",
+ VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP);
+ }
+ break;
+ default:
+ break;
}
- break;
- case ON_OFF_AUTO_OFF:
- if (!virtio_mem_has_shared_zeropage(rb)) {
- warn_report("'%s' property set to 'off' with a memdev that
does"
- " not support the shared zeropage.",
- VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP);
- }
- break;
- default:
- break;
+ } else if (vmem->unplugged_inaccessible != ON_OFF_AUTO_ON) {
+ error_setg(errp, "guest requires property '%s' to be 'on'",
+ VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP);
+ return;
}
-#else /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
- vmem->unplugged_inaccessible = ON_OFF_AUTO_ON;
-#endif /* VIRTIO_MEM_HAS_LEGACY_GUESTS */
@@ -1713,6 +1722,4 @@ static const Property virtio_mem_properties[] = {
TYPE_MEMORY_BACKEND, HostMemoryBackend *),
-#if defined(VIRTIO_MEM_HAS_LEGACY_GUESTS)
DEFINE_PROP_ON_OFF_AUTO(VIRTIO_MEM_UNPLUGGED_INACCESSIBLE_PROP,
VirtIOMEM,
unplugged_inaccessible, ON_OFF_AUTO_ON),
-#endif
DEFINE_PROP_BOOL(VIRTIO_MEM_EARLY_MIGRATION_PROP, VirtIOMEM,
---
but I thought either you didn't like the approach or it was too early
to propose for the API, so I went back to strcmp.
For a first version, I think that the first solution is enough.
