[v2,06/14] s390x: introduce s390_get_memory_limit()

Commit Message

David Hildenbrand Oct. 8, 2024, 10:54 a.m. UTC

Let's add s390_get_memory_limit(), to query what has been successfully
set via s390_set_memory_limit(). Allow setting the limit only once.

We'll remember the limit in the machine state. Move
s390_set_memory_limit() to machine code, merging it into
set_memory_limit(), because this really is a machine property.

Acked-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: David Hildenbrand <[e-mail]>
---
 hw/s390x/s390-virtio-ccw.c         | 22 ++++++++++++++++++----
 include/hw/s390x/s390-virtio-ccw.h |  3 +++
 target/s390x/cpu-sysemu.c          |  8 --------
 target/s390x/cpu.h                 |  1 -
 4 files changed, 21 insertions(+), 13 deletions(-)

Comments

Thomas Huth Nov. 6, 2024, 5:08 p.m. UTC | #1

On 08/10/2024 12.54, David Hildenbrand wrote:
> Let's add s390_get_memory_limit(), to query what has been successfully
> set via s390_set_memory_limit(). Allow setting the limit only once.
> 
> We'll remember the limit in the machine state. Move
> s390_set_memory_limit() to machine code, merging it into
> set_memory_limit(), because this really is a machine property.
> 
> Acked-by: Michael S. Tsirkin <[e-mail]>
> Signed-off-by: David Hildenbrand <[e-mail]>
> ---

Reviewed-by: Thomas Huth <[e-mail]>

Patch

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index f4c4433b23..749d46e700 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -45,6 +45,7 @@ 
 #include "migration/blocker.h"
 #include "qapi/visitor.h"
 #include "hw/s390x/cpu-topology.h"
+#include "kvm/kvm_s390x.h"
 #include CONFIG_DEVICES
 
 static Error *pv_mig_blocker;
@@ -121,12 +122,16 @@  static void subsystem_reset(void)
     }
 }
 
-static void set_memory_limit(uint64_t new_limit)
+static void s390_set_memory_limit(S390CcwMachineState *s390ms,
+                                  uint64_t new_limit)
 {
     uint64_t hw_limit;
-    int ret;
+    int ret = 0;
 
-    ret = s390_set_memory_limit(new_limit, &hw_limit);
+    assert(!s390ms->memory_limit && new_limit);
+    if (kvm_enabled()) {
+        ret = kvm_s390_set_mem_limit(new_limit, &hw_limit);
+    }
     if (ret == -E2BIG) {
         error_report("host supports a maximum of %" PRIu64 " GB",
                      hw_limit / GiB);
@@ -135,10 +140,19 @@  static void set_memory_limit(uint64_t new_limit)
         error_report("setting the guest size failed");
         exit(EXIT_FAILURE);
     }
+    s390ms->memory_limit = new_limit;
+}
+
+uint64_t s390_get_memory_limit(S390CcwMachineState *s390ms)
+{
+    /* We expect to be called only after the limit was set. */
+    assert(s390ms->memory_limit);
+    return s390ms->memory_limit;
 }
 
 static void s390_memory_init(MachineState *machine)
 {
+    S390CcwMachineState *s390ms = S390_CCW_MACHINE(machine);
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = machine->ram;
     uint64_t ram_size = memory_region_size(ram);
@@ -154,7 +168,7 @@  static void s390_memory_init(MachineState *machine)
         exit(EXIT_FAILURE);
     }
 
-    set_memory_limit(ram_size);
+    s390_set_memory_limit(s390ms, ram_size);
 
     /* Map the initial memory. Must happen after setting the memory limit. */
     memory_region_add_subregion(sysmem, 0, ram);
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index 996864a34e..eb04542979 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -29,10 +29,13 @@  struct S390CcwMachineState {
     bool dea_key_wrap;
     bool pv;
     uint8_t loadparm[8];
+    uint64_t memory_limit;
 
     SCLPDevice *sclp;
 };
 
+uint64_t s390_get_memory_limit(S390CcwMachineState *s390ms);
+
 #define S390_PTF_REASON_NONE (0x00 << 8)
 #define S390_PTF_REASON_DONE (0x01 << 8)
 #define S390_PTF_REASON_BUSY (0x02 << 8)
diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
index 1cd30c1d84..3118a25fee 100644
--- a/target/s390x/cpu-sysemu.c
+++ b/target/s390x/cpu-sysemu.c
@@ -255,14 +255,6 @@  unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu)
     return s390_count_running_cpus();
 }
 
-int s390_set_memory_limit(uint64_t new_limit, uint64_t *hw_limit)
-{
-    if (kvm_enabled()) {
-        return kvm_s390_set_mem_limit(new_limit, hw_limit);
-    }
-    return 0;
-}
-
 void s390_set_max_pagesize(uint64_t pagesize, Error **errp)
 {
     if (kvm_enabled()) {
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 5ef61b1f75..b4506539f0 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -881,7 +881,6 @@  static inline void s390_do_cpu_load_normal(CPUState *cs, run_on_cpu_data arg)
 
 /* cpu.c */
 void s390_crypto_reset(void);
-int s390_set_memory_limit(uint64_t new_limit, uint64_t *hw_limit);
 void s390_set_max_pagesize(uint64_t pagesize, Error **errp);
 void s390_cmma_reset(void);
 void s390_enable_css_support(S390CPU *cpu);