From 9d913e012b4328dab3c6b4e07907f3b87675fede Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 19 Dec 2024 15:41:02 +0100 Subject: [PATCH] s390x/s390-virtio-ccw: don't crash on weird RAM sizes 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 Message-ID: <20241219144115.2820241-2-david@redhat.com> Acked-by: Michael S. Tsirkin Reviewed-by: Eric Farman Reviewed-by: Thomas Huth Acked-by: Janosch Frank Signed-off-by: David Hildenbrand (cherry picked from commit 14e568ab4836347481af2e334009c385f456a734) Signed-off-by: Michael Tokarev --- 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 fe03f716f3..53c62fb77c 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)) { + /* + * 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); + } + /* allocate RAM for core */ memory_region_add_subregion(sysmem, 0, ram);