These functions are based on the copy_pxx_range() functions defined in mm/memory.c. The main difference is that a level parameter is specified to indicate the page table level (PGD, P4D, PUD PMD, PTE) at which the copy should be done. Also functions don't use a vma parameter, and don't alter the source page table even if an entry is bad. Also kvm_copy_pte_range() can be called with a non page-aligned buffer, so the buffer should be aligned with the page start so that the entire buffer is mapped if the end of buffer crosses a page. These functions will be used to populate the KVM page table. Signed-off-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx> --- arch/x86/kvm/isolation.c | 229 ++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/isolation.h | 1 + 2 files changed, 230 insertions(+), 0 deletions(-) diff --git a/arch/x86/kvm/isolation.c b/arch/x86/kvm/isolation.c index b681e4f..4f1b511 100644 --- a/arch/x86/kvm/isolation.c +++ b/arch/x86/kvm/isolation.c @@ -450,6 +450,235 @@ static int kvm_set_pgd(pgd_t *pgd, pgd_t pgd_value) } +static int kvm_copy_pte_range(struct mm_struct *dst_mm, + struct mm_struct *src_mm, pmd_t *dst_pmd, + pmd_t *src_pmd, unsigned long addr, + unsigned long end) +{ + pte_t *src_pte, *dst_pte; + + dst_pte = kvm_pte_alloc(dst_mm, dst_pmd, addr); + if (IS_ERR(dst_pte)) + return PTR_ERR(dst_pte); + + addr &= PAGE_MASK; + src_pte = pte_offset_map(src_pmd, addr); + + do { + pr_debug("PTE: %lx/%lx set[%lx] = %lx\n", + addr, addr + PAGE_SIZE, (long)dst_pte, pte_val(*src_pte)); + set_pte_at(dst_mm, addr, dst_pte, *src_pte); + + } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr < end); + + return 0; +} + +static int kvm_copy_pmd_range(struct mm_struct *dst_mm, + struct mm_struct *src_mm, + pud_t *dst_pud, pud_t *src_pud, + unsigned long addr, unsigned long end, + enum page_table_level level) +{ + pmd_t *src_pmd, *dst_pmd; + unsigned long next; + int err; + + dst_pmd = kvm_pmd_alloc(dst_mm, dst_pud, addr); + if (IS_ERR(dst_pmd)) + return PTR_ERR(dst_pmd); + + src_pmd = pmd_offset(src_pud, addr); + + do { + next = pmd_addr_end(addr, end); + if (level == PGT_LEVEL_PMD || pmd_none(*src_pmd)) { + pr_debug("PMD: %lx/%lx set[%lx] = %lx\n", + addr, next, (long)dst_pmd, pmd_val(*src_pmd)); + err = kvm_set_pmd(dst_pmd, *src_pmd); + if (err) + return err; + continue; + } + + if (!pmd_present(*src_pmd)) { + pr_warn("PMD: not present for [%lx,%lx]\n", + addr, next - 1); + pmd_clear(dst_pmd); + continue; + } + + if (pmd_trans_huge(*src_pmd) || pmd_devmap(*src_pmd)) { + pr_debug("PMD: %lx/%lx set[%lx] = %lx (huge/devmap)\n", + addr, next, (long)dst_pmd, pmd_val(*src_pmd)); + err = kvm_set_pmd(dst_pmd, *src_pmd); + if (err) + return err; + continue; + } + + err = kvm_copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, + addr, next); + if (err) { + pr_err("PMD: ERR PTE addr=%lx next=%lx\n", addr, next); + return err; + } + + } while (dst_pmd++, src_pmd++, addr = next, addr < end); + + return 0; +} + +static int kvm_copy_pud_range(struct mm_struct *dst_mm, + struct mm_struct *src_mm, + p4d_t *dst_p4d, p4d_t *src_p4d, + unsigned long addr, unsigned long end, + enum page_table_level level) +{ + pud_t *src_pud, *dst_pud; + unsigned long next; + int err; + + dst_pud = kvm_pud_alloc(dst_mm, dst_p4d, addr); + if (IS_ERR(dst_pud)) + return PTR_ERR(dst_pud); + + src_pud = pud_offset(src_p4d, addr); + + do { + next = pud_addr_end(addr, end); + if (level == PGT_LEVEL_PUD || pud_none(*src_pud)) { + pr_debug("PUD: %lx/%lx set[%lx] = %lx\n", + addr, next, (long)dst_pud, pud_val(*src_pud)); + err = kvm_set_pud(dst_pud, *src_pud); + if (err) + return err; + continue; + } + + if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { + pr_debug("PUD: %lx/%lx set[%lx] = %lx (huge/devmap)\n", + addr, next, (long)dst_pud, pud_val(*src_pud)); + err = kvm_set_pud(dst_pud, *src_pud); + if (err) + return err; + continue; + } + + err = kvm_copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, + addr, next, level); + if (err) { + pr_err("PUD: ERR PMD addr=%lx next=%lx\n", addr, next); + return err; + } + + } while (dst_pud++, src_pud++, addr = next, addr < end); + + return 0; +} + +static int kvm_copy_p4d_range(struct mm_struct *dst_mm, + struct mm_struct *src_mm, + pgd_t *dst_pgd, pgd_t *src_pgd, + unsigned long addr, unsigned long end, + enum page_table_level level) +{ + p4d_t *src_p4d, *dst_p4d; + unsigned long next; + int err; + + dst_p4d = kvm_p4d_alloc(dst_mm, dst_pgd, addr); + if (IS_ERR(dst_p4d)) + return PTR_ERR(dst_p4d); + + src_p4d = p4d_offset(src_pgd, addr); + + do { + next = p4d_addr_end(addr, end); + if (level == PGT_LEVEL_P4D || p4d_none(*src_p4d)) { + pr_debug("P4D: %lx/%lx set[%lx] = %lx\n", + addr, next, (long)dst_p4d, p4d_val(*src_p4d)); + + err = kvm_set_p4d(dst_p4d, *src_p4d); + if (err) + return err; + continue; + } + + err = kvm_copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d, + addr, next, level); + if (err) { + pr_err("P4D: ERR PUD addr=%lx next=%lx\n", addr, next); + return err; + } + + } while (dst_p4d++, src_p4d++, addr = next, addr < end); + + return 0; +} + +static int kvm_copy_pgd_range(struct mm_struct *dst_mm, + struct mm_struct *src_mm, unsigned long addr, + unsigned long end, enum page_table_level level) +{ + pgd_t *src_pgd, *dst_pgd; + unsigned long next; + int err; + + dst_pgd = pgd_offset(dst_mm, addr); + src_pgd = pgd_offset(src_mm, addr); + + do { + next = pgd_addr_end(addr, end); + if (level == PGT_LEVEL_PGD || pgd_none(*src_pgd)) { + pr_debug("PGD: %lx/%lx set[%lx] = %lx\n", + addr, next, (long)dst_pgd, pgd_val(*src_pgd)); + err = kvm_set_pgd(dst_pgd, *src_pgd); + if (err) + return err; + continue; + } + + err = kvm_copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd, + addr, next, level); + if (err) { + pr_err("PGD: ERR P4D addr=%lx next=%lx\n", addr, next); + return err; + } + + } while (dst_pgd++, src_pgd++, addr = next, addr < end); + + return 0; +} + +/* + * Copy page table entries from the current page table (i.e. from the + * kernel page table) to the KVM page table. The level parameter specifies + * the page table level (PGD, P4D, PUD PMD, PTE) at which the copy should + * be done. + */ +static int kvm_copy_mapping(void *ptr, size_t size, enum page_table_level level) +{ + unsigned long addr = (unsigned long)ptr; + unsigned long end = addr + ((unsigned long)size); + + BUG_ON(current->mm == &kvm_mm); + pr_debug("KERNMAP COPY addr=%px size=%lx\n", ptr, size); + return kvm_copy_pgd_range(&kvm_mm, current->mm, addr, end, level); +} + + +/* + * Copy page table PTE entries from the current page table to the KVM + * page table. + */ +int kvm_copy_ptes(void *ptr, unsigned long size) +{ + return kvm_copy_mapping(ptr, size, PGT_LEVEL_PTE); +} +EXPORT_SYMBOL(kvm_copy_ptes); + + static int kvm_isolation_init_mm(void) { pgd_t *kvm_pgd; diff --git a/arch/x86/kvm/isolation.h b/arch/x86/kvm/isolation.h index aa5e979..e8c018a 100644 --- a/arch/x86/kvm/isolation.h +++ b/arch/x86/kvm/isolation.h @@ -16,5 +16,6 @@ static inline bool kvm_isolation(void) extern void kvm_isolation_enter(void); extern void kvm_isolation_exit(void); extern void kvm_may_access_sensitive_data(struct kvm_vcpu *vcpu); +extern int kvm_copy_ptes(void *ptr, unsigned long size); #endif -- 1.7.1