[PULL 13/15] target/s390x: Allow 2G hugepages guest backing

[Eric Farman <farman@linux.ibm.com>]

From: Claudio Imbrenda <imbrenda@linux.ibm.com>

Allow mapping guest with 2G hugepages on hosts that support it.

Rename kvm_s390_get_hpage_1m() to kvm_s390_get_hpage() to reflect that
it is not anymore limited only to 1m hpages.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20260805103728.97602-2-imbrenda@linux.ibm.com
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 target/s390x/diag.c          |  2 +-
 target/s390x/kvm/kvm.c       | 36 +++++++++++++++++-------------------
 target/s390x/kvm/kvm_s390x.h |  2 +-
 target/s390x/kvm/stubs.c     |  2 +-
 4 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/target/s390x/diag.c b/target/s390x/diag.c
index 80f0958478..46d191b87d 100644
--- a/target/s390x/diag.c
+++ b/target/s390x/diag.c
@@ -185,7 +185,7 @@ out:
             return false;
         }
 
-        if (kvm_enabled() && kvm_s390_get_hpage_1m()) {
+        if (kvm_enabled() && kvm_s390_get_hpage()) {
             error_report("Protected VMs can currently not be backed with "
                          "huge pages");
             env->regs[r1 + 1] = DIAG_308_RC_INVAL_FOR_PV;
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index 72031a5714..803b878b4f 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -145,7 +145,7 @@ static int cap_mem_op;
 static int cap_mem_op_extension;
 static int cap_s390_irq;
 static int cap_ri;
-static int cap_hpage_1m;
+static int cap_hpage;
 static int cap_vcpu_resets;
 static int cap_protected;
 static int cap_zpci_op;
@@ -231,7 +231,7 @@ static void kvm_s390_enable_cmma(void)
         .attr = KVM_S390_VM_MEM_ENABLE_CMMA,
     };
 
-    if (cap_hpage_1m) {
+    if (cap_hpage) {
         warn_report("CMM will not be enabled because it is not "
                     "compatible with huge memory backings.");
         return;
@@ -292,30 +292,28 @@ void kvm_s390_crypto_reset(void)
     }
 }
 
-void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp)
+static bool kvm_s390_pgsize_cap(uint32_t capa, const char *s, Error **errp)
 {
-    if (pagesize == 4 * KiB) {
-        return;
-    }
-
-    if (pagesize != 1 * MiB) {
-        error_setg(errp, "Memory backing with 2G pages was specified, "
-                   "but KVM does not support this memory backing");
-        return;
+    if (kvm_vm_enable_cap(kvm_state, capa, 0)) {
+        error_setg(errp, "Memory backing with %s pages was specified, "
+                   "but KVM does not support this memory backing", s);
+        return false;
     }
+    return true;
+}
 
-    if (kvm_vm_enable_cap(kvm_state, KVM_CAP_S390_HPAGE_1M, 0)) {
-        error_setg(errp, "Memory backing with 1M pages was specified, "
-                   "but KVM does not support this memory backing");
-        return;
+void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp)
+{
+    if (pagesize == MiB) {
+        cap_hpage = kvm_s390_pgsize_cap(KVM_CAP_S390_HPAGE_1M, "1M", errp);
+    } else if (pagesize != 4 * KiB) {
+        cap_hpage = 2 * kvm_s390_pgsize_cap(KVM_CAP_S390_HPAGE_2G, "2G", errp);
     }
-
-    cap_hpage_1m = 1;
 }
 
-int kvm_s390_get_hpage_1m(void)
+int kvm_s390_get_hpage(void)
 {
-    return cap_hpage_1m;
+    return cap_hpage;
 }
 
 static void ccw_machine_class_foreach(ObjectClass *oc, void *opaque)
diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
index 7b1cce3e60..3c4fa0489c 100644
--- a/target/s390x/kvm/kvm_s390x.h
+++ b/target/s390x/kvm/kvm_s390x.h
@@ -25,7 +25,7 @@ void kvm_s390_program_interrupt(S390CPU *cpu, uint16_t code);
 int kvm_s390_set_cpu_state(S390CPU *cpu, uint8_t cpu_state);
 void kvm_s390_vcpu_interrupt_pre_save(S390CPU *cpu);
 int kvm_s390_vcpu_interrupt_post_load(S390CPU *cpu);
-int kvm_s390_get_hpage_1m(void);
+int kvm_s390_get_hpage(void);
 int kvm_s390_get_protected_dump(void);
 int kvm_s390_get_ri(void);
 int kvm_s390_get_zpci_op(void);
diff --git a/target/s390x/kvm/stubs.c b/target/s390x/kvm/stubs.c
index 196127baa5..ebf3c83994 100644
--- a/target/s390x/kvm/stubs.c
+++ b/target/s390x/kvm/stubs.c
@@ -143,7 +143,7 @@ int kvm_s390_vcpu_interrupt_post_load(S390CPU *cpu)
     g_assert_not_reached();
 }
 
-int kvm_s390_get_hpage_1m(void)
+int kvm_s390_get_hpage(void)
 {
     g_assert_not_reached();
 }
-- 
2.55.0