[PATCH v13 02/14] KVM: Cache as_id in kvm_memory_slot

From: Peter Xu
Date: Wed Sep 30 2020 - 21:21:11 EST


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@xxxxxxxxxx>
Suggested-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 6 ++++++
2 files changed, 7 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 05e3c2fb3ef7..c6f45687ba89 100644
--- 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 68edd25dcb11..2e8539213125 100644
--- 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;
--
2.26.2