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SubjectRe: [PATCH v9 7/8] KVM: arm64: Update age handlers to support PUD hugepages
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On 10/31/2018 11:27 PM, Punit Agrawal wrote:
> In preparation for creating larger hugepages at Stage 2, add support
> to the age handling notifiers for PUD hugepages when encountered.
>
> Provide trivial helpers for arm32 to allow sharing code.
>
> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Christoffer Dall <christoffer.dall@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> ---
> arch/arm/include/asm/kvm_mmu.h | 6 +++++
> arch/arm64/include/asm/kvm_mmu.h | 5 ++++
> arch/arm64/include/asm/pgtable.h | 1 +
> virt/kvm/arm/mmu.c | 39 ++++++++++++++++----------------
> 4 files changed, 32 insertions(+), 19 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index fea5e723e3ac..e62f0913ce7d 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -117,6 +117,12 @@ static inline pud_t kvm_s2pud_mkyoung(pud_t pud)
> return pud;
> }
>
> +static inline bool kvm_s2pud_young(pud_t pud)
> +{
> + BUG();
> + return false;
> +}
> +
> static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
> {
> pte_val(pte) |= L_PTE_S2_RDWR;
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 612032bbb428..9f941f70775c 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -273,6 +273,11 @@ static inline pud_t kvm_s2pud_mkyoung(pud_t pud)
> return pud_mkyoung(pud);
> }
>
> +static inline bool kvm_s2pud_young(pud_t pud)
> +{
> + return pud_young(pud);
> +}
> +
> #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
>
> #ifdef __PAGETABLE_PMD_FOLDED
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index f51e2271e6a3..bb0f3f17a7a9 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -386,6 +386,7 @@ static inline int pmd_protnone(pmd_t pmd)
> #define pfn_pmd(pfn,prot) __pmd(__phys_to_pmd_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
> #define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot)
>
> +#define pud_young(pud) pte_young(pud_pte(pud))
> #define pud_mkyoung(pud) pte_pud(pte_mkyoung(pud_pte(pud)))
> #define pud_write(pud) pte_write(pud_pte(pud))
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index bd749601195f..3893ea6a50bf 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -1225,6 +1225,11 @@ static int stage2_pmdp_test_and_clear_young(pmd_t *pmd)
> return stage2_ptep_test_and_clear_young((pte_t *)pmd);
> }
>
> +static int stage2_pudp_test_and_clear_young(pud_t *pud)
> +{
> + return stage2_ptep_test_and_clear_young((pte_t *)pud);
> +}
> +
> /**
> * kvm_phys_addr_ioremap - map a device range to guest IPA
> *
> @@ -1932,42 +1937,38 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
>
> static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
> {
> + pud_t *pud;
> pmd_t *pmd;
> pte_t *pte;
>
> - WARN_ON(size != PAGE_SIZE && size != PMD_SIZE);
> - pmd = stage2_get_pmd(kvm, NULL, gpa);
> - if (!pmd || pmd_none(*pmd)) /* Nothing there */
> + WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
> + if (!stage2_get_leaf_entry(kvm, gpa, &pud, &pmd, &pte))
> return 0;
>
> - if (pmd_thp_or_huge(*pmd)) /* THP, HugeTLB */
> + if (pud)
> + return stage2_pudp_test_and_clear_young(pud);
> + else if (pmd)
> return stage2_pmdp_test_and_clear_young(pmd);
> -
> - pte = pte_offset_kernel(pmd, gpa);
> - if (pte_none(*pte))
> - return 0;
> -
> - return stage2_ptep_test_and_clear_young(pte);
> + else
> + return stage2_ptep_test_and_clear_young(pte);
> }
>
> static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data)
> {
> + pud_t *pud;
> pmd_t *pmd;
> pte_t *pte;
>
> - WARN_ON(size != PAGE_SIZE && size != PMD_SIZE);
> - pmd = stage2_get_pmd(kvm, NULL, gpa);
> - if (!pmd || pmd_none(*pmd)) /* Nothing there */
> + WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
> + if (!stage2_get_leaf_entry(kvm, gpa, &pud, &pmd, &pte))
> return 0;
>
> - if (pmd_thp_or_huge(*pmd)) /* THP, HugeTLB */
> + if (pud)
> + return kvm_s2pud_young(*pud);
> + else if (pmd)
> return pmd_young(*pmd);
> -
> - pte = pte_offset_kernel(pmd, gpa);
> - if (!pte_none(*pte)) /* Just a page... */
> + else
> return pte_young(*pte);
> -
> - return 0;
> }
>
> int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
>

If stage2_get_leaf_entry() is avoided (which it should be) some of the previous
patches can be folded into just a single one like defining new HW page table
definitions, arm32 trivial functions and PUD specific additions at various
stage 2 page table walkers etc.

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