KVM: ARM: Support hugetlbfs backed huge pages

Support huge pages in KVM/ARM and KVM/ARM64.  The pud_huge checking on
the unmap path may feel a bit silly as the pud_huge check is always
defined to false, but the compiler should be smart about this.

Note: This deals only with VMAs marked as huge which are allocated by
users through hugetlbfs only.  Transparent huge pages can only be
detected by looking at the underlying pages (or the page tables
themselves) and this patch so far simply maps these on a page-by-page
level in the Stage-2 page tables.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

2 files changed, 16 insertions, 3 deletions

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 9b28c41f4ba9..77de4a41cc50 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -62,6 +62,12 @@ phys_addr_t kvm_get_idmap_vector(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
+static inline void kvm_set_pmd(pmd_t *pmd, pmd_t new_pmd)
+{
+        *pmd = new_pmd;
+        flush_pmd_entry(pmd);
+}
+
 static inline void kvm_set_pte(pte_t *pte, pte_t new_pte)
 {
         *pte = new_pte;
@@ -103,9 +109,15 @@ static inline void kvm_set_s2pte_writable(pte_t *pte)
         pte_val(*pte) |= L_PTE_S2_RDWR;
 }
 
+static inline void kvm_set_s2pmd_writable(pmd_t *pmd)
+{
+        pmd_val(*pmd) |= L_PMD_S2_RDWR;
+}
+
 struct kvm;
 
-static inline void coherent_icache_guest_page(struct kvm *kvm, gfn_t gfn)
+static inline void coherent_icache_guest_page(struct kvm *kvm, hva_t hva,
+                                              unsigned long size)
 {
         /*
          * If we are going to insert an instruction page and the icache is
@@ -120,8 +132,7 @@ static inline void coherent_icache_guest_page(struct kvm *kvm, gfn_t gfn)
          * need any kind of flushing (DDI 0406C.b - Page B3-1392).
          */
         if (icache_is_pipt()) {
-                unsigned long hva = gfn_to_hva(kvm, gfn);
-                __cpuc_coherent_user_range(hva, hva + PAGE_SIZE);
+                __cpuc_coherent_user_range(hva, hva + size);
         } else if (!icache_is_vivt_asid_tagged()) {
                 /* any kind of VIPT cache */
                 __flush_icache_all();
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 5689c18c85f5..a331d2527342 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -126,6 +126,8 @@
 #define L_PTE_S2_RDONLY          (_AT(pteval_t, 1) << 6)   /* HAP[1]   */
 #define L_PTE_S2_RDWR            (_AT(pteval_t, 3) << 6)   /* HAP[2:1] */
 
+#define L_PMD_S2_RDWR            (_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */
+
 /*
  * Hyp-mode PL2 PTE definitions for LPAE.
  */