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-rw-r--r--target-s390x/kvm.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index ec08dd0474..47008c24f2 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -135,6 +135,41 @@ int kvm_arch_get_registers(CPUS390XState *env)
return 0;
}
+/*
+ * Legacy layout for s390:
+ * Older S390 KVM requires the topmost vma of the RAM to be
+ * smaller than an system defined value, which is at least 256GB.
+ * Larger systems have larger values. We put the guest between
+ * the end of data segment (system break) and this value. We
+ * use 32GB as a base to have enough room for the system break
+ * to grow. We also have to use MAP parameters that avoid
+ * read-only mapping of guest pages.
+ */
+static void *legacy_s390_alloc(ram_addr_t size)
+{
+ void *mem;
+
+ mem = mmap((void *) 0x800000000ULL, size,
+ PROT_EXEC|PROT_READ|PROT_WRITE,
+ MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+ if (mem == MAP_FAILED) {
+ fprintf(stderr, "Allocating RAM failed\n");
+ abort();
+ }
+ return mem;
+}
+
+void *kvm_arch_vmalloc(ram_addr_t size)
+{
+ /* Can we use the standard allocation ? */
+ if (kvm_check_extension(kvm_state, KVM_CAP_S390_GMAP) &&
+ kvm_check_extension(kvm_state, KVM_CAP_S390_COW)) {
+ return NULL;
+ } else {
+ return legacy_s390_alloc(size);
+ }
+}
+
int kvm_arch_insert_sw_breakpoint(CPUS390XState *env, struct kvm_sw_breakpoint *bp)
{
static const uint8_t diag_501[] = {0x83, 0x24, 0x05, 0x01};