KVM: Cache as_id in kvm_memory_slot

Cache the address space ID just like the slot ID.  It will be used in
order to fill in the dirty ring entries.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201014182700.2888246-7-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 05e3c2f..c6f4568 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -346,6 +346,7 @@ struct kvm_memory_slot {
        unsigned long userspace_addr;
        u32 flags;
        short id;
+       u16 as_id;
 };
 
 static inline unsigned long kvm_dirty_bitmap_bytes(struct kvm_memory_slot *memslot)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 68edd25..2e85392 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1247,6 +1247,11 @@ static int kvm_delete_memslot(struct kvm *kvm,
 
        memset(&new, 0, sizeof(new));
        new.id = old->id;
+       /*
+        * This is only for debugging purpose; it should never be referenced
+        * for a removed memslot.
+        */
+       new.as_id = as_id;
 
        r = kvm_set_memslot(kvm, mem, old, &new, as_id, KVM_MR_DELETE);
        if (r)
@@ -1313,6 +1318,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
        if (!mem->memory_size)
                return kvm_delete_memslot(kvm, mem, &old, as_id);
 
+       new.as_id = as_id;
        new.id = id;
        new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
        new.npages = mem->memory_size >> PAGE_SHIFT;