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Message-Id: <1557758315-12667-15-git-send-email-alexandre.chartre@oracle.com>
Date: Mon, 13 May 2019 16:38:22 +0200
From: Alexandre Chartre <alexandre.chartre@...cle.com>
To: pbonzini@...hat.com, rkrcmar@...hat.com, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, hpa@...or.com,
dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
kvm@...r.kernel.org, x86@...nel.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Cc: konrad.wilk@...cle.com, jan.setjeeilers@...cle.com,
liran.alon@...cle.com, jwadams@...gle.com,
alexandre.chartre@...cle.com
Subject: [RFC KVM 14/27] kvm/isolation: functions to copy page table entries for a VA range
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@...cle.com>
---
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
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