On 23.09.24 17:36, Thomas Huth wrote:
On 23/09/2024 11.19, David Hildenbrand wrote:
On 10.09.24 19:57, David Hildenbrand wrote:
KVM is not happy when starting a VM with weird RAM sizes:
# qemu-system-s390x --enable-kvm --nographic -m 1234K
qemu-system-s390x: kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION
failed, slot=0, start=0x0, size=0x244000: Invalid argument
kvm_set_phys_mem: error registering slot: Invalid argument
Aborted (core dumped)
Let's handle that in a better way by rejecting such weird RAM sizes
right from the start:
# qemu-system-s390x --enable-kvm --nographic -m 1234K
qemu-system-s390x: ram size must be multiples of 1 MiB
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
hw/s390x/s390-virtio-ccw.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 18240a0fd8..e30cf0a2a1 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -180,6 +180,17 @@ static void s390_memory_init(MemoryRegion *ram)
{
MemoryRegion *sysmem = get_system_memory();
+ if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
+ /*
+ * The SCLP cannot possibly expose smaller granularity right now
and KVM
+ * cannot handle smaller granularity. As we don't support NUMA, the
+ * region size directly corresponds to machine->ram_size, and the
region
+ * is a single RAM memory region.
+ */
+ error_report("ram size must be multiples of 1 MiB");
+ exit(EXIT_FAILURE);
+ }
I'll switch to
error_setg(&error_fatal, "ram size must be multiples of 1 MiB");
here, to avoid the manual exit().
Please someone shout if I should keep it as is.
Please keep it, according to include/qapi/error.h:
* Please don't error_setg(&error_fatal, ...), use error_report() and
* exit(), because that's more obvious.
Controversial, but will do. Thanks!
--
Cheers,
David / dhildenb
