From: Punit Agrawal punit.agrawal@arm.com
mainline inclusion from mainline-v5.0-rc1 commit 86d1c55ea605025f78d026e7fc3a2bb4c3fc2d6a category: feature feature: Support PUD hugepage at stage 2
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In preparation for creating PUD hugepages at stage 2, add support for detecting execute permissions on PUD page table entries. Faults due to lack of execute permissions on page table entries is used to perform i-cache invalidation on first execute.
Provide trivial implementations of arm32 helpers to allow sharing of code.
Signed-off-by: Punit Agrawal punit.agrawal@arm.com Reviewed-by: Christoffer Dall christoffer.dall@arm.com Cc: Russell King linux@armlinux.org.uk Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com [ Replaced BUG() => WARN_ON(1) in arm32 PUD helpers ] Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Zenghui Yu yuzenghui@huawei.com Reviewed-by: Hailiang Zhang zhang.zhanghailiang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm/include/asm/kvm_mmu.h | 6 ++++ arch/arm64/include/asm/kvm_mmu.h | 5 ++++ arch/arm64/include/asm/pgtable-hwdef.h | 2 ++ virt/kvm/arm/mmu.c | 53 ++++++++++++++++++++++++++++++---- 4 files changed, 61 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 0859139..0281257 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -102,6 +102,12 @@ static inline bool kvm_s2pud_readonly(pud_t *pud) return false; }
+static inline bool kvm_s2pud_exec(pud_t *pud) +{ + WARN_ON(1); + 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 eb50ba4..e07f5a1 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -261,6 +261,11 @@ static inline bool kvm_s2pud_readonly(pud_t *pudp) return kvm_s2pte_readonly((pte_t *)pudp); }
+static inline bool kvm_s2pud_exec(pud_t *pudp) +{ + return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN); +} + #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
#ifdef __PAGETABLE_PMD_FOLDED diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h index fd208ea..10ae592 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -193,6 +193,8 @@ #define PMD_S2_RDWR (_AT(pmdval_t, 3) << 6) /* HAP[2:1] */ #define PMD_S2_XN (_AT(pmdval_t, 2) << 53) /* XN[1:0] */
+#define PUD_S2_XN (_AT(pudval_t, 2) << 53) /* XN[1:0] */ + /* * Memory Attribute override for Stage-2 (MemAttr[3:0]) */ diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 21b8bf2..a8245db 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1083,23 +1083,66 @@ static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache return 0; }
-static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr) +/* + * stage2_get_leaf_entry - walk the stage2 VM page tables and return + * true if a valid and present leaf-entry is found. A pointer to the + * leaf-entry is returned in the appropriate level variable - pudpp, + * pmdpp, ptepp. + */ +static bool stage2_get_leaf_entry(struct kvm *kvm, phys_addr_t addr, + pud_t **pudpp, pmd_t **pmdpp, pte_t **ptepp) { + pud_t *pudp; pmd_t *pmdp; pte_t *ptep;
- pmdp = stage2_get_pmd(kvm, NULL, addr); + *pudpp = NULL; + *pmdpp = NULL; + *ptepp = NULL; + + pudp = stage2_get_pud(kvm, NULL, addr); + if (!pudp || stage2_pud_none(kvm, *pudp) || !stage2_pud_present(kvm, *pudp)) + return false; + + if (stage2_pud_huge(kvm, *pudp)) { + *pudpp = pudp; + return true; + } + + pmdp = stage2_pmd_offset(kvm, pudp, addr); if (!pmdp || pmd_none(*pmdp) || !pmd_present(*pmdp)) return false;
- if (pmd_thp_or_huge(*pmdp)) - return kvm_s2pmd_exec(pmdp); + if (pmd_thp_or_huge(*pmdp)) { + *pmdpp = pmdp; + return true; + }
ptep = pte_offset_kernel(pmdp, addr); if (!ptep || pte_none(*ptep) || !pte_present(*ptep)) return false;
- return kvm_s2pte_exec(ptep); + *ptepp = ptep; + return true; +} + +static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr) +{ + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep; + bool found; + + found = stage2_get_leaf_entry(kvm, addr, &pudp, &pmdp, &ptep); + if (!found) + return false; + + if (pudp) + return kvm_s2pud_exec(pudp); + else if (pmdp) + return kvm_s2pmd_exec(pmdp); + else + return kvm_s2pte_exec(ptep); }
static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,