Please follow the current convention for the subject of your patch (if
you do a git log --oneline on arch/arm64/kvm, all commit should have
the same style).
On Tue, 11 Mar 2025 04:03:18 +0000,
Zhenyu Ye <yezhenyu2@xxxxxxxxxx> wrote:
>
> From: eillon <yezhenyu2@xxxxxxxxxx>
>
> Since the ARMv8, the page entry has supported the DBM attribute.
> Support set the attr during user_mem_abort().
Not quite. ARMv8.1 added DBM, and that is still, to this day, an
optional functionality, including in ARMv9.5.
>
> Signed-off-by: eillon <yezhenyu2@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/kvm_pgtable.h | 3 +++
> arch/arm64/kvm/hyp/pgtable.c | 6 ++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index 6b9d274052c7..35648d7f08f5 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -86,6 +86,8 @@ typedef u64 kvm_pte_t;
>
> #define KVM_PTE_LEAF_ATTR_HI_S2_XN BIT(54)
>
> +#define KVM_PTE_LEAF_ATTR_HI_S2_DBM BIT(51)
> +
> #define KVM_PTE_LEAF_ATTR_HI_S1_GP BIT(50)
>
> #define KVM_PTE_LEAF_ATTR_S2_PERMS (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \
> @@ -252,6 +254,7 @@ enum kvm_pgtable_prot {
>
> KVM_PGTABLE_PROT_DEVICE = BIT(3),
> KVM_PGTABLE_PROT_NORMAL_NC = BIT(4),
> + KVM_PGTABLE_PROT_DBM = BIT(5),
>
> KVM_PGTABLE_PROT_SW0 = BIT(55),
> KVM_PGTABLE_PROT_SW1 = BIT(56),
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index df5cc74a7dd0..3ea6bdbc02a0 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -700,6 +700,9 @@ static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot p
> if (prot & KVM_PGTABLE_PROT_W)
> attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
>
> + if (prot & KVM_PGTABLE_PROT_DBM)
> + attr |= KVM_PTE_LEAF_ATTR_HI_S2_DBM;
> +
> if (!kvm_lpa2_is_enabled())
> attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
>
> @@ -1309,6 +1312,9 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
> if (prot & KVM_PGTABLE_PROT_W)
> set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
>
> + if (prot & KVM_PGTABLE_PROT_DBM)
> + set |= KVM_PTE_LEAF_ATTR_HI_S2_DBM;
> +
Why isn't that exclusive of PROT_W?
> if (prot & KVM_PGTABLE_PROT_X)
> clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
>
What is driving this KVM_PGTABLE_PROT_DBM bit?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
