target/riscv/kvm.c: remove group setting of KVM AIA if the machine only has 1 socket

The emulated AIA within the Linux kernel restores the HART index
of the IMSICs according to the configured AIA settings. During
this process, the group setting is used only when the machine
partitions harts into groups. It's unnecessary to set the group
configuration if the machine has only one socket, as its address
space might not contain the group shift.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20231218090543.22353-2-yongxuan.wang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 2c5217102c33d3b6306e1cb95aff95f63edb5324..841756ab9b1afc028dd501df69aac5e97f7e992c 100644 (file)
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1390,21 +1390,24 @@ void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
         exit(1);
     }
 
-    socket_bits = find_last_bit(&socket_count, BITS_PER_LONG) + 1;
-    ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
-                            KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS,
-                            &socket_bits, true, NULL);
-    if (ret < 0) {
-        error_report("KVM AIA: failed to set group_bits");
-        exit(1);
-    }
 
-    ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
-                            KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT,
-                            &group_shift, true, NULL);
-    if (ret < 0) {
-        error_report("KVM AIA: failed to set group_shift");
-        exit(1);
+    if (socket_count > 1) {
+        socket_bits = find_last_bit(&socket_count, BITS_PER_LONG) + 1;
+        ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
+                                KVM_DEV_RISCV_AIA_CONFIG_GROUP_BITS,
+                                &socket_bits, true, NULL);
+        if (ret < 0) {
+            error_report("KVM AIA: failed to set group_bits");
+            exit(1);
+        }
+
+        ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
+                                KVM_DEV_RISCV_AIA_CONFIG_GROUP_SHIFT,
+                                &group_shift, true, NULL);
+        if (ret < 0) {
+            error_report("KVM AIA: failed to set group_shift");
+            exit(1);
+        }
     }
 
     guest_bits = guest_num == 0 ? 0 :