| Message ID | 20200907152344.12978-17-will@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Rewrite page-table code and fault handling | expand |
Hi Will, Minor nitpick below. On 9/7/20 4:23 PM, Will Deacon wrote: > Add support for relaxing the permissions of a stage-2 mapping (i.e. > adding additional permissions) to the generic page-table code. > > Cc: Marc Zyngier <maz@kernel.org> > Cc: Quentin Perret <qperret@google.com> > Reviewed-by: Gavin Shan <gshan@redhat.com> > Signed-off-by: Will Deacon <will@kernel.org> > --- > arch/arm64/include/asm/kvm_pgtable.h | 17 +++++++++++++++++ > arch/arm64/kvm/hyp/pgtable.c | 20 ++++++++++++++++++++ > 2 files changed, 37 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h > index a776bcf74316..5ab4f852a463 100644 > --- a/arch/arm64/include/asm/kvm_pgtable.h > +++ b/arch/arm64/include/asm/kvm_pgtable.h > @@ -218,6 +218,23 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr); > */ > kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr); > > +/** > + * kvm_pgtable_stage2_relax_perms() - Relax the permissions enforced by a > + * page-table entry. > + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init(). > + * @addr: Intermediate physical address to identify the page-table entry. > + * @prot: Additional permissions to grant for the mapping. > + * > + * If there is a valid, leaf page-table entry used to translate @addr, then > + * relax the permissions in that entry according to the read, write and > + * execute permissions specified by @prot. No permissions are removed, and > + * TLB invalidation is performed after updating the entry. > + * > + * Return: 0 on success, negative error code on failure. > + */ > +int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, > + enum kvm_pgtable_prot prot); > + > /** > * kvm_pgtable_stage2_is_young() - Test whether a page-table entry has the > * access flag set. > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c > index ad18ce469041..df705533dc3f 100644 > --- a/arch/arm64/kvm/hyp/pgtable.c > +++ b/arch/arm64/kvm/hyp/pgtable.c > @@ -782,6 +782,26 @@ bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr) > return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF; > } > > +int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, > + enum kvm_pgtable_prot prot) > +{ > + int ret; > + kvm_pte_t set = 0, clr = 0; > + > + if (prot & KVM_PGTABLE_PROT_R) > + set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; > + > + if (prot & KVM_PGTABLE_PROT_W) > + set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; > + > + 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); The level 0 argument could be replaced by S2_NO_LEVEL_HINT, which is self explanatory. However, that means the file needs to include stage2_pgtable.h. Thanks, Alex > + return ret; > +} > + > static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, > enum kvm_pgtable_walk_flags flag, > void * const arg)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index a776bcf74316..5ab4f852a463 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -218,6 +218,23 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr); */ kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr); +/** + * kvm_pgtable_stage2_relax_perms() - Relax the permissions enforced by a + * page-table entry. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init(). + * @addr: Intermediate physical address to identify the page-table entry. + * @prot: Additional permissions to grant for the mapping. + * + * If there is a valid, leaf page-table entry used to translate @addr, then + * relax the permissions in that entry according to the read, write and + * execute permissions specified by @prot. No permissions are removed, and + * TLB invalidation is performed after updating the entry. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, + enum kvm_pgtable_prot prot); + /** * kvm_pgtable_stage2_is_young() - Test whether a page-table entry has the * access flag set. diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index ad18ce469041..df705533dc3f 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -782,6 +782,26 @@ bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr) return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF; } +int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, + enum kvm_pgtable_prot prot) +{ + int ret; + kvm_pte_t set = 0, clr = 0; + + if (prot & KVM_PGTABLE_PROT_R) + set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; + + if (prot & KVM_PGTABLE_PROT_W) + set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; + + 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); + return ret; +} + static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, enum kvm_pgtable_walk_flags flag, void * const arg)