ARM: KVM: simplify HYP mapping population

The way we populate HYP mappings is a bit convoluted, to say the least.
Passing a pointer around to keep track of the current PFN is quite
odd, and we end-up having two different PTE accessors for no good
reason.

Simplify the whole thing by unifying the two PTE accessors, passing
a pgprot_t around, and moving the various validity checks to the
upper layers.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>

1 files changed, 42 insertions, 60 deletions

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 2f12e4056408..30033219df84 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -125,54 +125,34 @@ void free_hyp_pmds(void)
 }
 
 static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
-                                    unsigned long end)
+                                    unsigned long end, unsigned long pfn,
+                                    pgprot_t prot)
 {
         pte_t *pte;
         unsigned long addr;
-        struct page *page;
 
-        for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
-                unsigned long hyp_addr = KERN_TO_HYP(addr);
-
-                pte = pte_offset_kernel(pmd, hyp_addr);
-                BUG_ON(!virt_addr_valid(addr));
-                page = virt_to_page(addr);
-                kvm_set_pte(pte, mk_pte(page, PAGE_HYP));
-        }
-}
-
-static void create_hyp_io_pte_mappings(pmd_t *pmd, unsigned long start,
-                                       unsigned long end,
-                                       unsigned long *pfn_base)
-{
-        pte_t *pte;
-        unsigned long addr;
-
-        for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
-                unsigned long hyp_addr = KERN_TO_HYP(addr);
-
-                pte = pte_offset_kernel(pmd, hyp_addr);
-                BUG_ON(pfn_valid(*pfn_base));
-                kvm_set_pte(pte, pfn_pte(*pfn_base, PAGE_HYP_DEVICE));
-                (*pfn_base)++;
+        for (addr = start; addr < end; addr += PAGE_SIZE) {
+                pte = pte_offset_kernel(pmd, addr);
+                kvm_set_pte(pte, pfn_pte(pfn, prot));
+                pfn++;
         }
 }
 
 static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
-                                   unsigned long end, unsigned long *pfn_base)
+                                   unsigned long end, unsigned long pfn,
+                                   pgprot_t prot)
 {
         pmd_t *pmd;
         pte_t *pte;
         unsigned long addr, next;
 
         for (addr = start; addr < end; addr = next) {
-                unsigned long hyp_addr = KERN_TO_HYP(addr);
-                pmd = pmd_offset(pud, hyp_addr);
+                pmd = pmd_offset(pud, addr);
 
                 BUG_ON(pmd_sect(*pmd));
 
                 if (pmd_none(*pmd)) {
-                        pte = pte_alloc_one_kernel(NULL, hyp_addr);
+                        pte = pte_alloc_one_kernel(NULL, addr);
                         if (!pte) {
                                 kvm_err("Cannot allocate Hyp pte\n");
                                 return -ENOMEM;
@@ -182,25 +162,17 @@ static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
 
                 next = pmd_addr_end(addr, end);
 
-                /*
-                 * If pfn_base is NULL, we map kernel pages into HYP with the
-                 * virtual address. Otherwise, this is considered an I/O
-                 * mapping and we map the physical region starting at
-                 * *pfn_base to [start, end[.
-                 */
-                if (!pfn_base)
-                        create_hyp_pte_mappings(pmd, addr, next);
-                else
-                        create_hyp_io_pte_mappings(pmd, addr, next, pfn_base);
+                create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
+                pfn += (next - addr) >> PAGE_SHIFT;
         }
 
         return 0;
 }
 
-static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
+static int __create_hyp_mappings(pgd_t *pgdp,
+                                 unsigned long start, unsigned long end,
+                                 unsigned long pfn, pgprot_t prot)
 {
-        unsigned long start = (unsigned long)from;
-        unsigned long end = (unsigned long)to;
         pgd_t *pgd;
         pud_t *pud;
         pmd_t *pmd;
@@ -209,21 +181,14 @@ static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
 
         if (start >= end)
                 return -EINVAL;
-        /* Check for a valid kernel memory mapping */
-        if (!pfn_base && (!virt_addr_valid(from) || !virt_addr_valid(to - 1)))
-                return -EINVAL;
-        /* Check for a valid kernel IO mapping */
-        if (pfn_base && (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1)))
-                return -EINVAL;
 
         mutex_lock(&kvm_hyp_pgd_mutex);
-        for (addr = start; addr < end; addr = next) {
-                unsigned long hyp_addr = KERN_TO_HYP(addr);
-                pgd = hyp_pgd + pgd_index(hyp_addr);
-                pud = pud_offset(pgd, hyp_addr);
+        for (addr = start & PAGE_MASK; addr < end; addr = next) {
+                pgd = pgdp + pgd_index(addr);
+                pud = pud_offset(pgd, addr);
 
                 if (pud_none_or_clear_bad(pud)) {
-                        pmd = pmd_alloc_one(NULL, hyp_addr);
+                        pmd = pmd_alloc_one(NULL, addr);
                         if (!pmd) {
                                 kvm_err("Cannot allocate Hyp pmd\n");
                                 err = -ENOMEM;
@@ -233,9 +198,10 @@ static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base)
                 }
 
                 next = pgd_addr_end(addr, end);
-                err = create_hyp_pmd_mappings(pud, addr, next, pfn_base);
+                err = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);
                 if (err)
                         goto out;
+                pfn += (next - addr) >> PAGE_SHIFT;
         }
 out:
         mutex_unlock(&kvm_hyp_pgd_mutex);
@@ -255,22 +221,38 @@ out:
  */
 int create_hyp_mappings(void *from, void *to)
 {
-        return __create_hyp_mappings(from, to, NULL);
+        unsigned long phys_addr = virt_to_phys(from);
+        unsigned long start = KERN_TO_HYP((unsigned long)from);
+        unsigned long end = KERN_TO_HYP((unsigned long)to);
+
+        /* Check for a valid kernel memory mapping */
+        if (!virt_addr_valid(from) || !virt_addr_valid(to - 1))
+                return -EINVAL;
+
+        return __create_hyp_mappings(hyp_pgd, start, end,
+                                     __phys_to_pfn(phys_addr), PAGE_HYP);
 }
 
 /**
  * create_hyp_io_mappings - duplicate a kernel IO mapping into Hyp mode
  * @from:       The kernel start VA of the range
  * @to:         The kernel end VA of the range (exclusive)
- * @addr:       The physical start address which gets mapped
+ * @phys_addr:  The physical start address which gets mapped
  *
  * The resulting HYP VA is the same as the kernel VA, modulo
  * HYP_PAGE_OFFSET.
  */
-int create_hyp_io_mappings(void *from, void *to, phys_addr_t addr)
+int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
 {
-        unsigned long pfn = __phys_to_pfn(addr);
-        return __create_hyp_mappings(from, to, &pfn);
+        unsigned long start = KERN_TO_HYP((unsigned long)from);
+        unsigned long end = KERN_TO_HYP((unsigned long)to);
+
+        /* Check for a valid kernel IO mapping */
+        if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
+                return -EINVAL;
+
+        return __create_hyp_mappings(hyp_pgd, start, end,
+                                     __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
 }
 
 /**