Commit b259d137 authored by Will Deacon's avatar Will Deacon Committed by Marc Zyngier
Browse files

KVM: arm64: Pass level hint to TLBI during stage-2 permission fault 



Alex pointed out that we don't pass a level hint to the TLBI instruction
when handling a stage-2 permission fault, even though the walker does
at some point have the level information in its hands.

Rework stage2_update_leaf_attrs() so that it can optionally return the
level of the updated pte to its caller, which can in turn be used to
provide the correct TLBI level hint.

Reported-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/595cc73e-636e-8b3a-f93a-b4e9fb218db8@arm.com
Link: https://lore.kernel.org/r/20200930131801.16889-1-will@kernel.org
parent c9c0279c

arch/arm64/kvm/hyp/pgtable.c

+16 −7
Original line number Diff line number Diff line
@@ -694,6 +694,7 @@ struct stage2_attr_data { 
	kvm_pte_t	attr_set;

	kvm_pte_t	attr_clr;

	kvm_pte_t	pte;

	u32		level;

};



static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
@@ -706,6 +707,7 @@ static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 
	if (!kvm_pte_valid(pte))

		return 0;



	data->level = level;

	data->pte = pte;

	pte &= ~data->attr_clr;

	pte |= data->attr_set;
@@ -723,7 +725,8 @@ static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 


static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,

				    u64 size, kvm_pte_t attr_set,

				    kvm_pte_t attr_clr, kvm_pte_t *orig_pte)

				    kvm_pte_t attr_clr, kvm_pte_t *orig_pte,

				    u32 *level)

{

	int ret;

	kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
@@ -743,20 +746,24 @@ static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr, 


	if (orig_pte)

		*orig_pte = data.pte;



	if (level)

		*level = data.level;

	return 0;

}



int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)

{

	return stage2_update_leaf_attrs(pgt, addr, size, 0,

					KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W, NULL);

					KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,

					NULL, NULL);

}



kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)

{

	kvm_pte_t pte = 0;

	stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,

				 &pte);

				 &pte, NULL);

	dsb(ishst);

	return pte;

}
@@ -765,7 +772,7 @@ kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr) 
{

	kvm_pte_t pte = 0;

	stage2_update_leaf_attrs(pgt, addr, 1, 0, KVM_PTE_LEAF_ATTR_LO_S2_AF,

				 &pte);

				 &pte, NULL);

	/*

	 * "But where's the TLBI?!", you scream.

	 * "Over in the core code", I sigh.
@@ -778,7 +785,7 @@ kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr) 
bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr)

{

	kvm_pte_t pte = 0;

	stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte);

	stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte, NULL);

	return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF;

}
@@ -786,6 +793,7 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, 
				   enum kvm_pgtable_prot prot)

{

	int ret;

	u32 level;

	kvm_pte_t set = 0, clr = 0;



	if (prot & KVM_PGTABLE_PROT_R)
@@ -797,8 +805,9 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, 
	if (prot & KVM_PGTABLE_PROT_X)

		clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;



	ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL);

	kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, 0);

	ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level);

	if (!ret)

		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, level);

	return ret;

}

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