On Tue, Jul 06, 2010, Dong, Eddie wrote about "RE: [PATCH 8/24] Hold a vmcs02
for each vmcs12":
> > +/* Allocate an L0 VMCS (vmcs02) for the current L1 VMCS (vmcs12), if
> > one + * does not already exist. The allocation is done in L0 memory,
>...
> > +static int nested_create_current_vmcs(struct kvm_vcpu *vcpu)
> > +{
> > + struct vmcs_list *new_l2_guest;
> > + struct vmcs *l2_vmcs;
> > +
> > + if (nested_get_current_vmcs(vcpu))
> > + return 0; /* nothing to do - we already have a VMCS */
> > +
> > + if (to_vmx(vcpu)->nested.l2_vmcs_num >= NESTED_MAX_VMCS)
> > + return -ENOMEM;
> > +
> > + new_l2_guest = (struct vmcs_list *)
> > + kmalloc(sizeof(struct vmcs_list), GFP_KERNEL);
> > + if (!new_l2_guest)
> > + return -ENOMEM;
> > +
> > + l2_vmcs = alloc_vmcs();
>
> I didn't see where it was used. Hints on the usage?
Hi, I'm afraid I didn't understand the question. Where is what used?
What nested_create_current_vmcs does (as the comment above it explains) is
to allocate a vmcs02 for the current vmcs12, or return one that has been
previously allocated (and saved in a list we hold of these mappings).
The alloc_vmcs() call you pointed to happens when there isn't yet a vmcs02
for this vmcs12, and we need to allocate a new one. A few lines down this
new mapping between a vmcs12 address to vmcs02 is put in new_l2_guest and
that is inserted into the list of mappings.
Does this answer your question?
By the way, in my latest version of the code, l2_vmcs is now better named,
"vmcs02" :-)
> > + if (!l2_vmcs) {
> > + kfree(new_l2_guest);
> > + return -ENOMEM;
> > + }
> > +
> > + new_l2_guest->vmcs_addr = to_vmx(vcpu)->nested.current_vmptr;
> > + new_l2_guest->l2_vmcs = l2_vmcs;
> > + list_add(&(new_l2_guest->list),
> > &(to_vmx(vcpu)->nested.l2_vmcs_list));
> > + to_vmx(vcpu)->nested.l2_vmcs_num++; + return 0;
> > +}
--
Nadav Har'El | Monday, Aug 2 2010, 22 Av 5770
[email protected] |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |A computer program does what you tell it
http://nadav.harel.org.il |to do, not what you want it to do.
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