Marking PTs young (set AF bit) should be atomic to avoid cover dirty status set by hardware.
Signed-off-by: Keqian Zhu <[email protected]> --- arch/arm64/include/asm/kvm_mmu.h | 32 ++++++++++++++++++++++---------- arch/arm64/kvm/mmu.c | 15 ++++++++------- 2 files changed, 30 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index e0ee6e23d626..51af71505fbc 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -215,6 +215,18 @@ static inline void kvm_set_s2pte_readonly(pte_t *ptep) } while (pteval != old_pteval); } +static inline void kvm_set_s2pte_young(pte_t *ptep) +{ + pteval_t old_pteval, pteval; + + pteval = READ_ONCE(pte_val(*ptep)); + do { + old_pteval = pteval; + pteval |= PTE_AF; + pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); + } while (pteval != old_pteval); +} + static inline bool kvm_s2pte_readonly(pte_t *ptep) { return (READ_ONCE(pte_val(*ptep)) & PTE_S2_RDWR) == PTE_S2_RDONLY; @@ -230,6 +242,11 @@ static inline void kvm_set_s2pmd_readonly(pmd_t *pmdp) kvm_set_s2pte_readonly((pte_t *)pmdp); } +static inline void kvm_set_s2pmd_young(pmd_t *pmdp) +{ + kvm_set_s2pte_young((pte_t *)pmdp); +} + static inline bool kvm_s2pmd_readonly(pmd_t *pmdp) { return kvm_s2pte_readonly((pte_t *)pmdp); @@ -245,6 +262,11 @@ static inline void kvm_set_s2pud_readonly(pud_t *pudp) kvm_set_s2pte_readonly((pte_t *)pudp); } +static inline void kvm_set_s2pud_young(pud_t *pudp) +{ + kvm_set_s2pte_young((pte_t *)pudp); +} + static inline bool kvm_s2pud_readonly(pud_t *pudp) { return kvm_s2pte_readonly((pte_t *)pudp); @@ -255,16 +277,6 @@ static inline bool kvm_s2pud_exec(pud_t *pudp) return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN); } -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); -} - #ifdef CONFIG_ARM64_HW_AFDBM static inline bool kvm_hw_dbm_enabled(void) { diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 8c0035cab6b6..5ad87bce23c0 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2008,8 +2008,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, * Resolve the access fault by making the page young again. * Note that because the faulting entry is guaranteed not to be * cached in the TLB, we don't need to invalidate anything. - * Only the HW Access Flag updates are supported for Stage 2 (no DBM), - * so there is no need for atomic (pte|pmd)_mkyoung operations. + * + * Note: Both DBM and HW AF updates are supported for Stage2, so + * young operations should be atomic. */ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) { @@ -2027,15 +2028,15 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) goto out; if (pud) { /* HugeTLB */ - *pud = kvm_s2pud_mkyoung(*pud); + kvm_set_s2pud_young(pud); pfn = kvm_pud_pfn(*pud); pfn_valid = true; } else if (pmd) { /* THP, HugeTLB */ - *pmd = pmd_mkyoung(*pmd); + kvm_set_s2pmd_young(pmd); pfn = pmd_pfn(*pmd); pfn_valid = true; - } else { - *pte = pte_mkyoung(*pte); /* Just a page... */ + } else { /* Just a page... */ + kvm_set_s2pte_young(pte); pfn = pte_pfn(*pte); pfn_valid = true; } @@ -2280,7 +2281,7 @@ static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, u64 size, void * return 0; if (pud) - return kvm_s2pud_young(*pud); + return pud_young(*pud); else if (pmd) return pmd_young(*pmd); else -- 2.19.1
