Re: [PATCH] KVM: Fix srcu struct leakage

[Avi Kivity <avi@redhat.com>]

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

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).

-- 
error compiling committee.c: too many arguments to function