Re: [PATCH v2 04/16] kvm: Return number of free memslots

David Hildenbrand
2023-09-06T14:14:56Z

On 29.08.23 00:26, Philippe Mathieu-Daudé wrote:
> On 25/8/23 15:21, David Hildenbrand wrote:
>> Let's return the number of free slots instead of only checking if there
>> is a free slot. While at it, check all address spaces, which will also
>> consider SMM under x86 correctly.
>>
>> Make the stub return UINT_MAX, such that we can call the function
>> unconditionally.
>>
>> This is a preparation for memory devices that consume multiple memslots.
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>> accel/kvm/kvm-all.c | 33 ++++++++++++++++++++-------------
>> accel/stubs/kvm-stub.c | 4 ++--
>> hw/mem/memory-device.c | 2 +-
>> include/sysemu/kvm.h | 2 +-
>> include/sysemu/kvm_int.h | 1 +
>> 5 files changed, 25 insertions(+), 17 deletions(-)
>
>
>> diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
>> index 235dc661bc..f39997d86e 100644
>> --- a/accel/stubs/kvm-stub.c
>> +++ b/accel/stubs/kvm-stub.c
>> @@ -109,9 +109,9 @@ int kvm_irqchip_remove_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
>> return -ENOSYS;
>> }
>>
>> -bool kvm_has_free_slot(MachineState *ms)
>> +unsigned int kvm_get_free_memslots(void)
>> {
>> - return false;
>> + return UINT_MAX;
>
> Isn't it clearer returning 0 here and keeping kvm_enabled() below?

I tried doing it similarly to vhost_has_free_slot().

Also simplifies patch #12 :)

No strong opinion, though.

>
>
>> diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
>> index 511b42bde5..8b09e78b12 100644
>> --- a/include/sysemu/kvm_int.h
>> +++ b/include/sysemu/kvm_int.h
>> @@ -40,6 +40,7 @@ typedef struct KVMMemoryUpdate {
>> typedef struct KVMMemoryListener {
>> MemoryListener listener;
>> KVMSlot *slots;
>> + int nr_used_slots;
>
> Preferably using 'unsigned' here:

Sure, that should work.

>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Thanks!

--
Cheers,

David / dhildenb