KVM: arm/arm64: fix HYP ID map extension to 52 bits

Commit fa2a8445b1d3 incorrectly masks the index of the HYP ID map pgd
entry, causing a non-VHE kernel to hang during boot. This happens when
VA_BITS=48 and the ID map text is in 52-bit physical memory. In this
case we don't need an extra table level but need more entries in the
top-level table, so we need to map into hyp_pgd and need to use
__kvm_idmap_ptrs_per_pgd to mask in the extra bits. However,
__create_hyp_mappings currently masks by PTRS_PER_PGD instead.

Fix it so that we always use __kvm_idmap_ptrs_per_pgd for the HYP ID
map. This ensures that we use the larger mask for the top-level ID map
table when it has more entries. In all other cases, PTRS_PER_PGD is used
as normal.

Fixes: fa2a8445b1d3 ("arm64: allow ID map to be extended to 52 bits")
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 761787befd3b..876caf531d32 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -623,21 +623,15 @@ static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
         return 0;
 }
 
-static int __create_hyp_mappings(pgd_t *pgdp,
+static int __create_hyp_mappings(pgd_t *pgdp, unsigned long ptrs_per_pgd,
                                  unsigned long start, unsigned long end,
                                  unsigned long pfn, pgprot_t prot)
 {
         pgd_t *pgd;
         pud_t *pud;
-        unsigned long addr, next, ptrs_per_pgd = PTRS_PER_PGD;
+        unsigned long addr, next;
         int err = 0;
 
-        /*
-         * If it's not the hyp_pgd, fall back to the kvm idmap layout.
-         */
-        if (pgdp != hyp_pgd)
-                ptrs_per_pgd = __kvm_idmap_ptrs_per_pgd();
-
         mutex_lock(&kvm_hyp_pgd_mutex);
         addr = start & PAGE_MASK;
         end = PAGE_ALIGN(end);
@@ -705,8 +699,8 @@ int create_hyp_mappings(void *from, void *to, pgprot_t prot)
                 int err;
 
                 phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
-                err = __create_hyp_mappings(hyp_pgd, virt_addr,
-                                            virt_addr + PAGE_SIZE,
+                err = __create_hyp_mappings(hyp_pgd, PTRS_PER_PGD,
+                                            virt_addr, virt_addr + PAGE_SIZE,
                                             __phys_to_pfn(phys_addr),
                                             prot);
                 if (err)
@@ -737,7 +731,7 @@ int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
         if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
                 return -EINVAL;
 
-        return __create_hyp_mappings(hyp_pgd, start, end,
+        return __create_hyp_mappings(hyp_pgd, PTRS_PER_PGD, start, end,
                                      __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
 }
 
@@ -1743,7 +1737,7 @@ static int kvm_map_idmap_text(pgd_t *pgd)
         int err;
 
         /* Create the idmap in the boot page tables */
-        err =   __create_hyp_mappings(pgd,
+        err =   __create_hyp_mappings(pgd, __kvm_idmap_ptrs_per_pgd(),
                                       hyp_idmap_start, hyp_idmap_end,
                                       __phys_to_pfn(hyp_idmap_start),
                                       PAGE_HYP_EXEC);