Re: [PATCH 6/7] kvm mmu: enabling 1GB pages by extending backing_size funtion

[Avi Kivity]

Joerg Roedel wrote:

This patch enables support for 1GB pages in KVM by implementing
the support in backing_size().

@@ -490,18 +492,30 @@ static enum kvm_page_size host_page_size(struct kvm *kvm, 
gfn_t gfn)
 static enum kvm_page_size backing_size(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
        struct kvm_memory_slot *slot;
-
-       if (has_wrprotected_page(vcpu->kvm, gfn))
-               return KVM_PAGE_SIZE_4k;
-
-       if (host_page_size(vcpu->kvm, gfn) < KVM_PAGE_SIZE_2M)
-               return KVM_PAGE_SIZE_4k;
+       enum kvm_page_size host_size, ret;

slot = gfn_to_memslot(vcpu->kvm, gfn);

        if (slot && slot->dirty_bitmap)
                return KVM_PAGE_SIZE_4k;

- return KVM_PAGE_SIZE_2M;

+       host_size = host_page_size(vcpu->kvm, gfn);
+
+       switch (host_size) {
+       case KVM_PAGE_SIZE_1G:
+               if (!has_wrprotected_largepage(vcpu->kvm, gfn)) {
+                       ret = KVM_PAGE_SIZE_1G;
+                       break;
+               }

What if there's a wrprotected_page in there?

+       case KVM_PAGE_SIZE_2M:
+               if (!has_wrprotected_page(vcpu->kvm, gfn)) {
+                       ret = KVM_PAGE_SIZE_2M;
+                       break;
+               }
+       default:
+               ret = KVM_PAGE_SIZE_4k;
+       }
+
+       return ret;
 }

/*

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

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