KVM: Remove the usage of page->private field by rmap

When kvm uses user-allocated pages in the future for the guest, we won't
be able to use page->private for rmap, since page->rmap is reserved for
the filesystem.  So we move the rmap base pointers to the memory slot.

A side effect of this is that we need to store the gfn of each gpte in
the shadow pages, since the memory slot is addressed by gfn, instead of
hfn like struct page.

Signed-off-by: Izik Eidus <izik@qumranet.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 888b0924c17b..9510e2276ca3 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -309,6 +309,8 @@ static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
                                         __free_page(free->phys_mem[i]);
                         vfree(free->phys_mem);
                 }
+        if (!dont || free->rmap != dont->rmap)
+                vfree(free->rmap);
 
         if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
                 vfree(free->dirty_bitmap);
@@ -719,13 +721,18 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
                 if (!new.phys_mem)
                         goto out_unlock;
 
+                new.rmap = vmalloc(npages * sizeof(struct page*));
+
+                if (!new.rmap)
+                        goto out_unlock;
+
                 memset(new.phys_mem, 0, npages * sizeof(struct page *));
+                memset(new.rmap, 0, npages * sizeof(*new.rmap));
                 for (i = 0; i < npages; ++i) {
                         new.phys_mem[i] = alloc_page(GFP_HIGHUSER
                                                      | __GFP_ZERO);
                         if (!new.phys_mem[i])
                                 goto out_unlock;
-                        set_page_private(new.phys_mem[i],0);
                 }
         }
 
@@ -909,7 +916,7 @@ static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
         return r;
 }
 
-static gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
+gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
 {
         int i;
         struct kvm_mem_alias *alias;