arm64: allow ID map to be extended to 52 bits
Currently, when using VA_BITS < 48, if the ID map text happens to be
placed in physical memory above VA_BITS, we increase the VA size (up to
48) and create a new table level, in order to map in the ID map text.
This is okay because the system always supports 48 bits of VA.
This patch extends the code such that if the system supports 52 bits of
VA, and the ID map text is placed that high up, then we increase the VA
size accordingly, up to 52.
One difference from the current implementation is that so far the
condition of VA_BITS < 48 has meant that the top level table is always
"full", with the maximum number of entries, and an extra table level is
always needed. Now, when VA_BITS = 48 (and using 64k pages), the top
level table is not full, and we simply need to increase the number of
entries in it, instead of creating a new table level.
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[catalin.marinas@arm.com: reduce arguments to __create_hyp_mappings()]
[catalin.marinas@arm.com: reworked/renamed __cpu_uses_extended_idmap_level()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 8dbec68..8c5643e 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -211,6 +211,11 @@
return false;
}
+static inline unsigned long __kvm_idmap_ptrs_per_pgd(void)
+{
+ return PTRS_PER_PGD;
+}
+
static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
pgd_t *hyp_pgd,
pgd_t *merged_hyp_pgd,
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 49ea3de..942fdb5 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -344,10 +344,8 @@
* tcr_set_idmap_t0sz - update TCR.T0SZ so that we can load the ID map
*/
.macro tcr_set_idmap_t0sz, valreg, tmpreg
-#ifndef CONFIG_ARM64_VA_BITS_48
ldr_l \tmpreg, idmap_t0sz
bfi \valreg, \tmpreg, #TCR_T0SZ_OFFSET, #TCR_TxSZ_WIDTH
-#endif
.endm
/*
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index b3f7b68..b33bdb5 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -273,7 +273,12 @@
static inline bool __kvm_cpu_uses_extended_idmap(void)
{
- return __cpu_uses_extended_idmap();
+ return __cpu_uses_extended_idmap_level();
+}
+
+static inline unsigned long __kvm_idmap_ptrs_per_pgd(void)
+{
+ return idmap_ptrs_per_pgd;
}
/*
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index accc2ff3..88451d4 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -63,6 +63,7 @@
* physical memory, in which case it will be smaller.
*/
extern u64 idmap_t0sz;
+extern u64 idmap_ptrs_per_pgd;
static inline bool __cpu_uses_extended_idmap(void)
{
@@ -71,6 +72,15 @@
}
/*
+ * True if the extended ID map requires an extra level of translation table
+ * to be configured.
+ */
+static inline bool __cpu_uses_extended_idmap_level(void)
+{
+ return ARM64_HW_PGTABLE_LEVELS((64 - idmap_t0sz)) > CONFIG_PGTABLE_LEVELS;
+}
+
+/*
* Set TCR.T0SZ to its default value (based on VA_BITS)
*/
static inline void __cpu_set_tcr_t0sz(unsigned long t0sz)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index eeec000..66f0186 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -176,7 +176,7 @@
* ptrs: #imm pointers per table page
*
* Preserves: virt
- * Corrupts: tmp1, tmp2
+ * Corrupts: ptrs, tmp1, tmp2
* Returns: tbl -> next level table page address
*/
.macro create_table_entry, tbl, virt, shift, ptrs, tmp1, tmp2
@@ -184,7 +184,8 @@
phys_to_pte \tmp1, \tmp2
orr \tmp2, \tmp2, #PMD_TYPE_TABLE // address of next table and entry type
lsr \tmp1, \virt, #\shift
- and \tmp1, \tmp1, #\ptrs - 1 // table index
+ sub \ptrs, \ptrs, #1
+ and \tmp1, \tmp1, \ptrs // table index
str \tmp2, [\tbl, \tmp1, lsl #3]
add \tbl, \tbl, #PAGE_SIZE // next level table page
.endm
@@ -194,15 +195,17 @@
* block entry in the next level (tbl) for the given virtual address.
*
* Preserves: tbl, next, virt
- * Corrupts: tmp1, tmp2
+ * Corrupts: ptrs_per_pgd, tmp1, tmp2
*/
- .macro create_pgd_entry, tbl, virt, tmp1, tmp2
- create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2
+ .macro create_pgd_entry, tbl, virt, ptrs_per_pgd, tmp1, tmp2
+ create_table_entry \tbl, \virt, PGDIR_SHIFT, \ptrs_per_pgd, \tmp1, \tmp2
#if SWAPPER_PGTABLE_LEVELS > 3
- create_table_entry \tbl, \virt, PUD_SHIFT, PTRS_PER_PUD, \tmp1, \tmp2
+ mov \ptrs_per_pgd, PTRS_PER_PUD
+ create_table_entry \tbl, \virt, PUD_SHIFT, \ptrs_per_pgd, \tmp1, \tmp2
#endif
#if SWAPPER_PGTABLE_LEVELS > 2
- create_table_entry \tbl, \virt, SWAPPER_TABLE_SHIFT, PTRS_PER_PTE, \tmp1, \tmp2
+ mov \ptrs_per_pgd, PTRS_PER_PTE
+ create_table_entry \tbl, \virt, SWAPPER_TABLE_SHIFT, \ptrs_per_pgd, \tmp1, \tmp2
#endif
.endm
@@ -266,16 +269,34 @@
adrp x0, idmap_pg_dir
adrp x3, __idmap_text_start // __pa(__idmap_text_start)
-#ifndef CONFIG_ARM64_VA_BITS_48
+ /*
+ * VA_BITS may be too small to allow for an ID mapping to be created
+ * that covers system RAM if that is located sufficiently high in the
+ * physical address space. So for the ID map, use an extended virtual
+ * range in that case, and configure an additional translation level
+ * if needed.
+ *
+ * Calculate the maximum allowed value for TCR_EL1.T0SZ so that the
+ * entire ID map region can be mapped. As T0SZ == (64 - #bits used),
+ * this number conveniently equals the number of leading zeroes in
+ * the physical address of __idmap_text_end.
+ */
+ adrp x5, __idmap_text_end
+ clz x5, x5
+ cmp x5, TCR_T0SZ(VA_BITS) // default T0SZ small enough?
+ b.ge 1f // .. then skip VA range extension
+
+ adr_l x6, idmap_t0sz
+ str x5, [x6]
+ dmb sy
+ dc ivac, x6 // Invalidate potentially stale cache line
+
+#if (VA_BITS < 48)
#define EXTRA_SHIFT (PGDIR_SHIFT + PAGE_SHIFT - 3)
-#define EXTRA_PTRS (1 << (48 - EXTRA_SHIFT))
+#define EXTRA_PTRS (1 << (PHYS_MASK_SHIFT - EXTRA_SHIFT))
/*
- * If VA_BITS < 48, it may be too small to allow for an ID mapping to be
- * created that covers system RAM if that is located sufficiently high
- * in the physical address space. So for the ID map, use an extended
- * virtual range in that case, by configuring an additional translation
- * level.
+ * If VA_BITS < 48, we have to configure an additional table level.
* First, we have to verify our assumption that the current value of
* VA_BITS was chosen such that all translation levels are fully
* utilised, and that lowering T0SZ will always result in an additional
@@ -285,27 +306,19 @@
#error "Mismatch between VA_BITS and page size/number of translation levels"
#endif
+ mov x4, EXTRA_PTRS
+ create_table_entry x0, x3, EXTRA_SHIFT, x4, x5, x6
+#else
/*
- * Calculate the maximum allowed value for TCR_EL1.T0SZ so that the
- * entire ID map region can be mapped. As T0SZ == (64 - #bits used),
- * this number conveniently equals the number of leading zeroes in
- * the physical address of __idmap_text_end.
+ * If VA_BITS == 48, we don't have to configure an additional
+ * translation level, but the top-level table has more entries.
*/
- adrp x5, __idmap_text_end
- clz x5, x5
- cmp x5, TCR_T0SZ(VA_BITS) // default T0SZ small enough?
- b.ge 1f // .. then skip additional level
-
- adr_l x6, idmap_t0sz
- str x5, [x6]
- dmb sy
- dc ivac, x6 // Invalidate potentially stale cache line
-
- create_table_entry x0, x3, EXTRA_SHIFT, EXTRA_PTRS, x5, x6
-1:
+ mov x4, #1 << (PHYS_MASK_SHIFT - PGDIR_SHIFT)
+ str_l x4, idmap_ptrs_per_pgd, x5
#endif
-
- create_pgd_entry x0, x3, x5, x6
+1:
+ ldr_l x4, idmap_ptrs_per_pgd
+ create_pgd_entry x0, x3, x4, x5, x6
mov x5, x3 // __pa(__idmap_text_start)
adr_l x6, __idmap_text_end // __pa(__idmap_text_end)
create_block_map x0, x7, x3, x5, x6, x4
@@ -316,7 +329,8 @@
adrp x0, swapper_pg_dir
mov_q x5, KIMAGE_VADDR + TEXT_OFFSET // compile time __va(_text)
add x5, x5, x23 // add KASLR displacement
- create_pgd_entry x0, x5, x3, x6
+ mov x4, PTRS_PER_PGD
+ create_pgd_entry x0, x5, x4, x3, x6
adrp x6, _end // runtime __pa(_end)
adrp x3, _text // runtime __pa(_text)
sub x6, x6, x3 // _end - _text
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index f9681cc..33c40b3 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -72,24 +72,23 @@
mov x5, #TCR_EL2_RES1
orr x4, x4, x5
-#ifndef CONFIG_ARM64_VA_BITS_48
/*
- * If we are running with VA_BITS < 48, we may be running with an extra
- * level of translation in the ID map. This is only the case if system
- * RAM is out of range for the currently configured page size and number
- * of translation levels, in which case we will also need the extra
- * level for the HYP ID map, or we won't be able to enable the EL2 MMU.
+ * The ID map may be configured to use an extended virtual address
+ * range. This is only the case if system RAM is out of range for the
+ * currently configured page size and VA_BITS, in which case we will
+ * also need the extended virtual range for the HYP ID map, or we won't
+ * be able to enable the EL2 MMU.
*
* However, at EL2, there is only one TTBR register, and we can't switch
* between translation tables *and* update TCR_EL2.T0SZ at the same
- * time. Bottom line: we need the extra level in *both* our translation
- * tables.
+ * time. Bottom line: we need to use the extended range with *both* our
+ * translation tables.
*
* So use the same T0SZ value we use for the ID map.
*/
ldr_l x5, idmap_t0sz
bfi x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
-#endif
+
/*
* Set the PS bits in TCR_EL2.
*/
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 0c631a1..baa3441 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -50,6 +50,7 @@
#define NO_CONT_MAPPINGS BIT(1)
u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
+u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
u64 kimage_voffset __ro_after_init;
EXPORT_SYMBOL(kimage_voffset);
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index b36945d..761787b 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -629,14 +629,20 @@
{
pgd_t *pgd;
pud_t *pud;
- unsigned long addr, next;
+ unsigned long addr, next, ptrs_per_pgd = PTRS_PER_PGD;
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);
do {
- pgd = pgdp + pgd_index(addr);
+ pgd = pgdp + ((addr >> PGDIR_SHIFT) & (ptrs_per_pgd - 1));
if (pgd_none(*pgd)) {
pud = pud_alloc_one(NULL, addr);