Am 09.11.2010 15:30, Avi Kivity wrote:
> On 11/09/2010 04:07 PM, Jan Kiszka wrote:
>>>
>>> kvm_iommu_unmap_guest enters SRCU critical section, and "struct kvm" is
>>> freed at the end of kvm_arch_destroy_vm. Thats why its not in generic
>>> code.
>>
>> The problem is the arch-specific allocation of the kvm object on IA64.
>> All others simply call kmalloc/kzalloc for the struct itself, but IA64
>> embeds it into some larger context. Not sure why, though.
>
> ia64 virt is special - the guest has a virtual address space for host
> data. This data is shared with the host address space, but on different
> addresses.
>
> I guess to reduce tlb costs ia64 kvm uses a large order allocation for
> both struct kvm and other random data, which is why the allocation is
> different.
>
> It could be refactored to something like
>
> #ifndef CONFIG_HAVE_SPECIAL_KVM_ALLOC
>
> static inline struct kvm *kvm_arch_alloc_vm(void)
> {
> return kzalloc(...);
> }
>
> static inline void kvm_arch_free_vm(struct kvm *kvm)
> {
> kfree(kvm);
> }
>
> #endif
Yep, that's what I'm already working on.
>
> and have ia64 provide its special stuff. The practice of duplicating
> common code just because of one outlier is bad, there are better ways.
>
> (and I will accept untested ia64 patches provided kvm-ia64@ is copied).
OK, will come. Refactoring will affect all archs, so all need to test
and ack.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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