Commit 8942a237 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Introduce KVM_PGTABLE_S2_IDMAP stage 2 flag 



Introduce a new stage 2 configuration flag to specify that all mappings
in a given page-table will be identity-mapped, as will be the case for
the host. This allows to introduce sanity checks in the map path and to
avoid programming errors.

Suggested-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-34-qperret@google.com
parent bc224df1

arch/arm64/include/asm/kvm_pgtable.h

+2 −0
Original line number Diff line number Diff line
@@ -60,9 +60,11 @@ struct kvm_pgtable_mm_ops { 
 * enum kvm_pgtable_stage2_flags - Stage-2 page-table flags.

 * @KVM_PGTABLE_S2_NOFWB:	Don't enforce Normal-WB even if the CPUs have

 *				ARM64_HAS_STAGE2_FWB.

 * @KVM_PGTABLE_S2_IDMAP:	Only use identity mappings.

 */

enum kvm_pgtable_stage2_flags {

	KVM_PGTABLE_S2_NOFWB			= BIT(0),

	KVM_PGTABLE_S2_IDMAP			= BIT(1),

};



/**

arch/arm64/kvm/hyp/pgtable.c

+3 −0
Original line number Diff line number Diff line
@@ -760,6 +760,9 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, 
		.arg		= &map_data,

	};



	if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys)))

		return -EINVAL;



	ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);

	if (ret)

		return ret;