kvm arm: Move fake PGD handling to arch specific files

Rearrange the code for fake pgd handling, which is applicable
only for arm64. This will later be removed once we introduce
the stage2 page table walker macros.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 22732a5e3119..9a3409f7b37a 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -208,6 +208,49 @@ static inline unsigned int kvm_get_hwpgd_size(void)
 	return PTRS_PER_S2_PGD * sizeof(pgd_t);
 }
 
+/*
+ * Allocate fake pgd for the host kernel page table macros to work.
+ * This is not used by the hardware and we have no alignment
+ * requirement for this allocation.
+ */
+static inline pgd_t *kvm_setup_fake_pgd(pgd_t *hwpgd)
+{
+	int i;
+	pgd_t *pgd;
+
+	if (!KVM_PREALLOC_LEVEL)
+		return hwpgd;
+
+	/*
+	 * When KVM_PREALLOC_LEVEL==2, we allocate a single page for
+	 * the PMD and the kernel will use folded pud.
+	 * When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
+	 * pages.
+	 */
+
+	pgd = kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
+			GFP_KERNEL | __GFP_ZERO);
+	if (!pgd)
+		return ERR_PTR(-ENOMEM);
+
+	/* Plug the HW PGD into the fake one. */
+	for (i = 0; i < PTRS_PER_S2_PGD; i++) {
+		if (KVM_PREALLOC_LEVEL == 1)
+			pgd_populate(NULL, pgd + i,
+				     (pud_t *)hwpgd + i * PTRS_PER_PUD);
+		else if (KVM_PREALLOC_LEVEL == 2)
+			pud_populate(NULL, pud_offset(pgd, 0) + i,
+				     (pmd_t *)hwpgd + i * PTRS_PER_PMD);
+	}
+
+	return pgd;
+}
+
+static inline void kvm_free_fake_pgd(pgd_t *pgd)
+{
+	if (KVM_PREALLOC_LEVEL > 0)
+		kfree(pgd);
+}
 static inline bool kvm_page_empty(void *ptr)
 {
 	struct page *ptr_page = virt_to_page(ptr);