From 4f853a714bf16338ff5261128e6c7ae2569e9505 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Fri, 9 May 2014 23:31:31 +0200 Subject: [PATCH] arm/arm64: KVM: Fix and refactor unmap_range unmap_range() was utterly broken, to quote Marc, and broke in all sorts of situations. It was also quite complicated to follow and didn't follow the usual scheme of having a separate iterating function for each level of page tables. Address this by refactoring the code and introduce a pgd_clear() function. Reviewed-by: Jungseok Lee Reviewed-by: Mario Smarduch Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/include/asm/kvm_mmu.h | 12 +++ arch/arm/kvm/mmu.c | 157 +++++++++++++++++-------------- arch/arm64/include/asm/kvm_mmu.h | 15 +++ 3 files changed, 111 insertions(+), 73 deletions(-) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 5c7aa3c1519f..5cc0b0f5f72f 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -127,6 +127,18 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd) (__boundary - 1 < (end) - 1)? __boundary: (end); \ }) +static inline bool kvm_page_empty(void *ptr) +{ + struct page *ptr_page = virt_to_page(ptr); + return page_count(ptr_page) == 1; +} + + +#define kvm_pte_table_empty(ptep) kvm_page_empty(ptep) +#define kvm_pmd_table_empty(pmdp) kvm_page_empty(pmdp) +#define kvm_pud_table_empty(pudp) (0) + + struct kvm; #define kvm_flush_dcache_to_poc(a,l) __cpuc_flush_dcache_area((a), (l)) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 16f804938b8f..23360610aeac 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -90,104 +90,115 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc) return p; } -static bool page_empty(void *ptr) +static void clear_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr) { - struct page *ptr_page = virt_to_page(ptr); - return page_count(ptr_page) == 1; + pud_t *pud_table __maybe_unused = pud_offset(pgd, 0); + pgd_clear(pgd); + kvm_tlb_flush_vmid_ipa(kvm, addr); + pud_free(NULL, pud_table); + put_page(virt_to_page(pgd)); } static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr) { - if (pud_huge(*pud)) { - pud_clear(pud); - kvm_tlb_flush_vmid_ipa(kvm, addr); - } else { - pmd_t *pmd_table = pmd_offset(pud, 0); - pud_clear(pud); - kvm_tlb_flush_vmid_ipa(kvm, addr); - pmd_free(NULL, pmd_table); - } + pmd_t *pmd_table = pmd_offset(pud, 0); + VM_BUG_ON(pud_huge(*pud)); + pud_clear(pud); + kvm_tlb_flush_vmid_ipa(kvm, addr); + pmd_free(NULL, pmd_table); put_page(virt_to_page(pud)); } static void clear_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr) { - if (kvm_pmd_huge(*pmd)) { - pmd_clear(pmd); - kvm_tlb_flush_vmid_ipa(kvm, addr); - } else { - pte_t *pte_table = pte_offset_kernel(pmd, 0); - pmd_clear(pmd); - kvm_tlb_flush_vmid_ipa(kvm, addr); - pte_free_kernel(NULL, pte_table); - } + pte_t *pte_table = pte_offset_kernel(pmd, 0); + VM_BUG_ON(kvm_pmd_huge(*pmd)); + pmd_clear(pmd); + kvm_tlb_flush_vmid_ipa(kvm, addr); + pte_free_kernel(NULL, pte_table); put_page(virt_to_page(pmd)); } -static void clear_pte_entry(struct kvm *kvm, pte_t *pte, phys_addr_t addr) +static void unmap_ptes(struct kvm *kvm, pmd_t *pmd, + phys_addr_t addr, phys_addr_t end) { - if (pte_present(*pte)) { - kvm_set_pte(pte, __pte(0)); - put_page(virt_to_page(pte)); - kvm_tlb_flush_vmid_ipa(kvm, addr); - } + phys_addr_t start_addr = addr; + pte_t *pte, *start_pte; + + start_pte = pte = pte_offset_kernel(pmd, addr); + do { + if (!pte_none(*pte)) { + kvm_set_pte(pte, __pte(0)); + put_page(virt_to_page(pte)); + kvm_tlb_flush_vmid_ipa(kvm, addr); + } + } while (pte++, addr += PAGE_SIZE, addr != end); + + if (kvm_pte_table_empty(start_pte)) + clear_pmd_entry(kvm, pmd, start_addr); } -static void unmap_range(struct kvm *kvm, pgd_t *pgdp, - unsigned long long start, u64 size) +static void unmap_pmds(struct kvm *kvm, pud_t *pud, + phys_addr_t addr, phys_addr_t end) { - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - unsigned long long addr = start, end = start + size; - u64 next; + phys_addr_t next, start_addr = addr; + pmd_t *pmd, *start_pmd; - while (addr < end) { - pgd = pgdp + pgd_index(addr); - pud = pud_offset(pgd, addr); - pte = NULL; - if (pud_none(*pud)) { - addr = kvm_pud_addr_end(addr, end); - continue; - } - - if (pud_huge(*pud)) { - /* - * If we are dealing with a huge pud, just clear it and - * move on. - */ - clear_pud_entry(kvm, pud, addr); - addr = kvm_pud_addr_end(addr, end); - continue; + start_pmd = pmd = pmd_offset(pud, addr); + do { + next = kvm_pmd_addr_end(addr, end); + if (!pmd_none(*pmd)) { + if (kvm_pmd_huge(*pmd)) { + pmd_clear(pmd); + kvm_tlb_flush_vmid_ipa(kvm, addr); + put_page(virt_to_page(pmd)); + } else { + unmap_ptes(kvm, pmd, addr, next); + } } + } while (pmd++, addr = next, addr != end); - pmd = pmd_offset(pud, addr); - if (pmd_none(*pmd)) { - addr = kvm_pmd_addr_end(addr, end); - continue; - } + if (kvm_pmd_table_empty(start_pmd)) + clear_pud_entry(kvm, pud, start_addr); +} - if (!kvm_pmd_huge(*pmd)) { - pte = pte_offset_kernel(pmd, addr); - clear_pte_entry(kvm, pte, addr); - next = addr + PAGE_SIZE; - } +static void unmap_puds(struct kvm *kvm, pgd_t *pgd, + phys_addr_t addr, phys_addr_t end) +{ + phys_addr_t next, start_addr = addr; + pud_t *pud, *start_pud; - /* - * If the pmd entry is to be cleared, walk back up the ladder - */ - if (kvm_pmd_huge(*pmd) || (pte && page_empty(pte))) { - clear_pmd_entry(kvm, pmd, addr); - next = kvm_pmd_addr_end(addr, end); - if (page_empty(pmd) && !page_empty(pud)) { - clear_pud_entry(kvm, pud, addr); - next = kvm_pud_addr_end(addr, end); + start_pud = pud = pud_offset(pgd, addr); + do { + next = kvm_pud_addr_end(addr, end); + if (!pud_none(*pud)) { + if (pud_huge(*pud)) { + pud_clear(pud); + kvm_tlb_flush_vmid_ipa(kvm, addr); + put_page(virt_to_page(pud)); + } else { + unmap_pmds(kvm, pud, addr, next); } } + } while (pud++, addr = next, addr != end); - addr = next; - } + if (kvm_pud_table_empty(start_pud)) + clear_pgd_entry(kvm, pgd, start_addr); +} + + +static void unmap_range(struct kvm *kvm, pgd_t *pgdp, + phys_addr_t start, u64 size) +{ + pgd_t *pgd; + phys_addr_t addr = start, end = start + size; + phys_addr_t next; + + pgd = pgdp + pgd_index(addr); + do { + next = kvm_pgd_addr_end(addr, end); + unmap_puds(kvm, pgd, addr, next); + } while (pgd++, addr = next, addr != end); } static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd, diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 7d29847a893b..8e138c7c53ac 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -125,6 +125,21 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd) #define kvm_pud_addr_end(addr, end) pud_addr_end(addr, end) #define kvm_pmd_addr_end(addr, end) pmd_addr_end(addr, end) +static inline bool kvm_page_empty(void *ptr) +{ + struct page *ptr_page = virt_to_page(ptr); + return page_count(ptr_page) == 1; +} + +#define kvm_pte_table_empty(ptep) kvm_page_empty(ptep) +#ifndef CONFIG_ARM64_64K_PAGES +#define kvm_pmd_table_empty(pmdp) kvm_page_empty(pmdp) +#else +#define kvm_pmd_table_empty(pmdp) (0) +#endif +#define kvm_pud_table_empty(pudp) (0) + + struct kvm; #define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l)) -- 2.20.1