@@ -525,9 +525,7 @@ static void virtio_mem_activate_memslots_to_plug(VirtIOMEM *vmem,
vmem->memslot_size;
unsigned int idx;
- if (!vmem->dynamic_memslots) {
- return;
- }
+ assert(vmem->dynamic_memslots);
/* Activate all involved memslots in a single transaction. */
memory_region_transaction_begin();
@@ -547,9 +545,7 @@ static void virtio_mem_deactivate_unplugged_memslots(VirtIOMEM *vmem,
vmem->memslot_size;
unsigned int idx;
- if (!vmem->dynamic_memslots) {
- return;
- }
+ assert(vmem->dynamic_memslots);
/* Deactivate all memslots with unplugged blocks in a single transaction. */
memory_region_transaction_begin();
@@ -598,7 +594,9 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
virtio_mem_notify_unplug(vmem, offset, size);
virtio_mem_set_range_unplugged(vmem, start_gpa, size);
/* Deactivate completely unplugged memslots after updating the state. */
- virtio_mem_deactivate_unplugged_memslots(vmem, offset, size);
+ if (vmem->dynamic_memslots) {
+ virtio_mem_deactivate_unplugged_memslots(vmem, offset, size);
+ }
return 0;
}
@@ -635,9 +633,11 @@ static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
* blocks we are plugging here. The following notification will inform
* registered listeners about the blocks we're plugging.
*/
- virtio_mem_activate_memslots_to_plug(vmem, offset, size);
+ if (vmem->dynamic_memslots) {
+ virtio_mem_activate_memslots_to_plug(vmem, offset, size);
+ }
ret = virtio_mem_notify_plug(vmem, offset, size);
- if (ret) {
+ if (ret && vmem->dynamic_memslots) {
virtio_mem_deactivate_unplugged_memslots(vmem, offset, size);
}
}
@@ -749,7 +749,9 @@ static int virtio_mem_unplug_all(VirtIOMEM *vmem)
notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
/* Deactivate all memslots after updating the state. */
- virtio_mem_deactivate_unplugged_memslots(vmem, 0, region_size);
+ if (vmem->dynamic_memslots) {
+ virtio_mem_deactivate_unplugged_memslots(vmem, 0, region_size);
+ }
}
trace_virtio_mem_unplugged_all();
When running with "dynamic-memslots=off", we enter virtio_mem_activate_memslots_to_plug() to return immediately again because "vmem->dynamic_memslots == false". However, the compiler might not optimize out calculating start_idx+end_idx, where we divide by vmem->memslot_size. In such a configuration, the memslot size is 0 and we'll get a division by zero: (qemu) qom-set vmem0 requested-size 3G (qemu) q35.sh: line 38: 622940 Floating point exception(core dumped) The same is true for virtio_mem_deactivate_unplugged_memslots(), however we never really reach that code without a prior virtio_mem_activate_memslots_to_plug() call. Let's fix it by simply calling these functions only with "dynamic-memslots=on". This was found when using a debug build of QEMU. Message-ID: <20231023111341.219317-1-david@redhat.com> Reprted-by: Mario Casquero <mcasquer@redhat.com> Fixes: 177f9b1ee464 ("virtio-mem: Expose device memory dynamically via multiple memslots if enabled") Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Tested-by: Mario Casquero <mcasquer@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> --- hw/virtio/virtio-mem.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)