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Diffstat (limited to 'arch/powerpc/mm/pgtable-radix.c')
-rw-r--r--arch/powerpc/mm/pgtable-radix.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 5cc50d47ce3f..671a45d86c18 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -25,6 +25,9 @@
#include <trace/events/thp.h>
+unsigned int mmu_pid_bits;
+unsigned int mmu_base_pid;
+
static int native_register_process_table(unsigned long base, unsigned long pg_sz,
unsigned long table_size)
{
@@ -261,11 +264,34 @@ static void __init radix_init_pgtable(void)
for_each_memblock(memory, reg)
WARN_ON(create_physical_mapping(reg->base,
reg->base + reg->size));
+
+ /* Find out how many PID bits are supported */
+ if (cpu_has_feature(CPU_FTR_HVMODE)) {
+ if (!mmu_pid_bits)
+ mmu_pid_bits = 20;
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ /*
+ * When KVM is possible, we only use the top half of the
+ * PID space to avoid collisions between host and guest PIDs
+ * which can cause problems due to prefetch when exiting the
+ * guest with AIL=3
+ */
+ mmu_base_pid = 1 << (mmu_pid_bits - 1);
+#else
+ mmu_base_pid = 1;
+#endif
+ } else {
+ /* The guest uses the bottom half of the PID space */
+ if (!mmu_pid_bits)
+ mmu_pid_bits = 19;
+ mmu_base_pid = 1;
+ }
+
/*
* Allocate Partition table and process table for the
* host.
*/
- BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
+ BUG_ON(PRTB_SIZE_SHIFT > 36);
process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
/*
* Fill in the process table.
@@ -339,6 +365,12 @@ static int __init radix_dt_scan_page_sizes(unsigned long node,
if (type == NULL || strcmp(type, "cpu") != 0)
return 0;
+ /* Find MMU PID size */
+ prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
+ if (prop && size == 4)
+ mmu_pid_bits = be32_to_cpup(prop);
+
+ /* Grab page size encodings */
prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
if (!prop)
return 0;