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Commit 00f034a1 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: do not bias the generation number in kvm_current_mmio_generation 



The next patch will give a meaning (a la seqcount) to the low bit of the
generation number.  Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().

Cc: stable@vger.kernel.org
Reviewed-by: default avatarDavid Matlack <dmatlack@google.com>
Reviewed-by: default avatarXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fd275235

arch/x86/kvm/mmu.c

+1 −6
Original line number Diff line number Diff line
@@ -236,12 +236,7 @@ static unsigned int get_mmio_spte_generation(u64 spte) 


static unsigned int kvm_current_mmio_generation(struct kvm *kvm)

{

	/*

	 * Init kvm generation close to MMIO_MAX_GEN to easily test the

	 * code of handling generation number wrap-around.

	 */

	return (kvm_memslots(kvm)->generation +

		      MMIO_MAX_GEN - 150) & MMIO_GEN_MASK;

	return kvm_memslots(kvm)->generation & MMIO_GEN_MASK;

}



static void mark_mmio_spte(struct kvm *kvm, u64 *sptep, u64 gfn,

virt/kvm/kvm_main.c

+7 −0
Original line number Diff line number Diff line
@@ -477,6 +477,13 @@ static struct kvm *kvm_create_vm(unsigned long type) 
	kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);

	if (!kvm->memslots)

		goto out_err_no_srcu;



	/*

	 * Init kvm generation close to the maximum to easily test the

	 * code of handling generation number wrap-around.

	 */

	kvm->memslots->generation = -150;



	kvm_init_memslots_id(kvm);

	if (init_srcu_struct(&kvm->srcu))

		goto out_err_no_srcu;