From: Fuad Tabba <tabba@google.com>
To: Quentin Perret <qperret@google.com>
Cc: maz@kernel.org, james.morse@arm.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
ardb@kernel.org, qwandor@google.com, dbrazdil@google.com,
kernel-team@android.com
Subject: Re: [PATCH v3 16/21] KVM: arm64: Enable retrieving protections attributes of PTEs
Date: Mon, 2 Aug 2021 16:52:49 +0200 [thread overview]
Message-ID: <CA+EHjTwL+grX__03SfeDdxeppjSovEZhKRvqjmA_4kSBwsjswg@mail.gmail.com> (raw)
In-Reply-To: <20210729132818.4091769-17-qperret@google.com>
Hi Quentin,
On Thu, Jul 29, 2021 at 3:29 PM Quentin Perret <qperret@google.com> wrote:
>
> Introduce helper functions in the KVM stage-2 and stage-1 page-table
> manipulation library allowing to retrieve the enum kvm_pgtable_prot of a
> PTE. This will be useful to implement custom walkers outside of
> pgtable.c.
>
> Signed-off-by: Quentin Perret <qperret@google.com>
> ---
> arch/arm64/include/asm/kvm_pgtable.h | 20 +++++++++++++++
> arch/arm64/kvm/hyp/pgtable.c | 37 ++++++++++++++++++++++++++++
> 2 files changed, 57 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index d5ca9b6ce241..7ff9f52239ba 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -505,4 +505,24 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
> */
> int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
> kvm_pte_t *ptep, u32 *level);
> +
> +/**
> + * kvm_pgtable_stage2_pte_prot() - Retrieve the protection attributes of a
> + * stage-2 Page-Table Entry.
> + * @pte: Page-table entry
> + *
> + * Return: protection attributes of the page-table entry in the enum
> + * kvm_pgtable_prot format.
> + */
> +enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
> +
> +/**
> + * kvm_pgtable_hyp_pte_prot() - Retrieve the protection attributes of a stage-1
> + * Page-Table Entry.
> + * @pte: Page-table entry
> + *
> + * Return: protection attributes of the page-table entry in the enum
> + * kvm_pgtable_prot format.
> + */
> +enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
> #endif /* __ARM64_KVM_PGTABLE_H__ */
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index 1915489bb127..a6eda8f23cb6 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -363,6 +363,26 @@ static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
> return 0;
> }
>
> +enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
> +{
> + enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
> + u32 ap;
> +
> + if (!kvm_pte_valid(pte))
> + return prot;
> +
> + if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN))
> + prot |= KVM_PGTABLE_PROT_X;
> +
> + ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte);
> + if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO)
> + prot |= KVM_PGTABLE_PROT_R;
> + else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW)
> + prot |= KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W;
nit: why not use the freshly minted KVM_PGTABLE_PROT_RW?
Thanks,
/fuad
> +
> + return prot;
> +}
> +
> static bool hyp_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
> {
> /*
> @@ -565,6 +585,23 @@ static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot p
> return 0;
> }
>
> +enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
> +{
> + enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
> +
> + if (!kvm_pte_valid(pte))
> + return prot;
> +
> + if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
> + prot |= KVM_PGTABLE_PROT_R;
> + if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
> + prot |= KVM_PGTABLE_PROT_W;
> + if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
> + prot |= KVM_PGTABLE_PROT_X;
> +
> + return prot;
> +}
> +
> static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
> {
> if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
> --
> 2.32.0.432.gabb21c7263-goog
>
next prev parent reply other threads:[~2021-08-02 14:53 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-29 13:27 [PATCH v3 00/21] Track shared pages at EL2 in protected mode Quentin Perret
2021-07-29 13:27 ` [PATCH v3 01/21] KVM: arm64: Add hyp_spin_is_locked() for basic locking assertions at EL2 Quentin Perret
2021-07-29 13:27 ` [PATCH v3 02/21] KVM: arm64: Introduce hyp_assert_lock_held() Quentin Perret
2021-07-29 13:28 ` [PATCH v3 03/21] KVM: arm64: Provide the host_stage2_try() helper macro Quentin Perret
2021-08-02 9:36 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 04/21] KVM: arm64: Introduce helper to retrieve a PTE and its level Quentin Perret
2021-07-29 13:28 ` [PATCH v3 05/21] KVM: arm64: Expose page-table helpers Quentin Perret
2021-07-29 13:28 ` [PATCH v3 06/21] KVM: arm64: Optimize host memory aborts Quentin Perret
2021-08-02 9:37 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 07/21] KVM: arm64: Rename KVM_PTE_LEAF_ATTR_S2_IGNORED Quentin Perret
2021-08-02 9:37 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 08/21] KVM: arm64: Don't overwrite software bits with owner id Quentin Perret
2021-08-02 9:38 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 09/21] KVM: arm64: Tolerate re-creating hyp mappings to set software bits Quentin Perret
2021-08-02 9:50 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 10/21] KVM: arm64: Enable forcing page-level stage-2 mappings Quentin Perret
2021-08-02 9:49 ` Fuad Tabba
2021-08-03 10:13 ` Quentin Perret
2021-08-03 10:43 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 11/21] KVM: arm64: Allow populating software bits Quentin Perret
2021-07-29 13:28 ` [PATCH v3 12/21] KVM: arm64: Add helpers to tag shared pages in SW bits Quentin Perret
2021-08-02 10:30 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 13/21] KVM: arm64: Expose host stage-2 manipulation helpers Quentin Perret
2021-08-02 11:13 ` Fuad Tabba
2021-08-03 10:20 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 14/21] KVM: arm64: Expose pkvm_hyp_id Quentin Perret
2021-07-29 13:28 ` [PATCH v3 15/21] KVM: arm64: Introduce addr_is_memory() Quentin Perret
2021-08-02 14:52 ` Fuad Tabba
2021-08-03 10:23 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 16/21] KVM: arm64: Enable retrieving protections attributes of PTEs Quentin Perret
2021-08-02 14:52 ` Fuad Tabba [this message]
2021-08-03 10:24 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 17/21] KVM: arm64: Mark host bss and rodata section as shared Quentin Perret
2021-08-03 5:02 ` Fuad Tabba
2021-08-03 10:34 ` Quentin Perret
2021-08-03 10:54 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 18/21] KVM: arm64: Remove __pkvm_mark_hyp Quentin Perret
2021-07-29 13:28 ` [PATCH v3 19/21] KVM: arm64: Refactor protected nVHE stage-1 locking Quentin Perret
2021-08-03 5:31 ` Fuad Tabba
2021-08-03 10:37 ` Quentin Perret
2021-08-03 10:51 ` Fuad Tabba
2021-07-29 13:28 ` [PATCH v3 20/21] KVM: arm64: Restrict EL2 stage-1 changes in protected mode Quentin Perret
2021-08-03 8:22 ` Fuad Tabba
2021-08-03 10:43 ` Quentin Perret
2021-07-29 13:28 ` [PATCH v3 21/21] KVM: arm64: Make __pkvm_create_mappings static Quentin Perret
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