[1/4] KVM: Rename KVMState->nr_slots to nr_slots_max

Commit Message

Peter Xu Sept. 4, 2024, 7:16 p.m. UTC

This value used to reflect the maximum supported memslots from KVM kernel.
Rename it to be clearer, preparing for dynamic sized memslot allocations.

Signed-off-by: Peter Xu <[e-mail]>
---
 include/sysemu/kvm_int.h |  4 ++--
 accel/kvm/kvm-all.c      | 26 +++++++++++++-------------
 2 files changed, 15 insertions(+), 15 deletions(-)

Comments

David Hildenbrand Sept. 4, 2024, 8:36 p.m. UTC | #1

On 04.09.24 21:16, Peter Xu wrote:
> This value used to reflect the maximum supported memslots from KVM kernel.
> Rename it to be clearer, preparing for dynamic sized memslot allocations.

Well, it matches "KVM_CAP_NR_MEMSLOTS" :)

Reviewed-by: David Hildenbrand <[e-mail]>

> -    for (i = 0; i < s->nr_slots; i++) {
> +    for (i = 0; i < s->nr_slots_max; i++) {
>           mem = &kml->slots[i];
>           /* Discard slots that are empty or do not overlap the section */
>           if (!mem->memory_size ||
> @@ -1720,11 +1720,11 @@ static void kvm_log_sync_global(MemoryListener *l, bool last_stage)
>       kvm_dirty_ring_flush();
>   
>       /*
> -     * TODO: make this faster when nr_slots is big while there are
> +     * TODO: make this faster when nr_slots_max is big while there are
>        * only a few used slots (small VMs).
>        */

Interesting TODO!

Patch

diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 1d8fb1473b..e5de43619e 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -102,8 +102,8 @@  struct KVMDirtyRingReaper {
 struct KVMState
 {
     AccelState parent_obj;
-
-    int nr_slots;
+    /* Max number of KVM slots supported */
+    int nr_slots_max;
     int fd;
     int vmfd;
     int coalesced_mmio;
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 75d11a07b2..991c389adc 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -169,7 +169,7 @@  unsigned int kvm_get_max_memslots(void)
 {
     KVMState *s = KVM_STATE(current_accel());
 
-    return s->nr_slots;
+    return s->nr_slots_max;
 }
 
 unsigned int kvm_get_free_memslots(void)
@@ -187,7 +187,7 @@  unsigned int kvm_get_free_memslots(void)
     }
     kvm_slots_unlock();
 
-    return s->nr_slots - used_slots;
+    return s->nr_slots_max - used_slots;
 }
 
 /* Called with KVMMemoryListener.slots_lock held */
@@ -196,7 +196,7 @@  static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml)
     KVMState *s = kvm_state;
     int i;
 
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         if (kml->slots[i].memory_size == 0) {
             return &kml->slots[i];
         }
@@ -225,7 +225,7 @@  static KVMSlot *kvm_lookup_matching_slot(KVMMemoryListener *kml,
     KVMState *s = kvm_state;
     int i;
 
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         KVMSlot *mem = &kml->slots[i];
 
         if (start_addr == mem->start_addr && size == mem->memory_size) {
@@ -267,7 +267,7 @@  int kvm_physical_memory_addr_from_host(KVMState *s, void *ram,
     int i, ret = 0;
 
     kvm_slots_lock();
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         KVMSlot *mem = &kml->slots[i];
 
         if (ram >= mem->ram && ram < mem->ram + mem->memory_size) {
@@ -1071,7 +1071,7 @@  static int kvm_physical_log_clear(KVMMemoryListener *kml,
 
     kvm_slots_lock();
 
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         mem = &kml->slots[i];
         /* Discard slots that are empty or do not overlap the section */
         if (!mem->memory_size ||
@@ -1720,11 +1720,11 @@  static void kvm_log_sync_global(MemoryListener *l, bool last_stage)
     kvm_dirty_ring_flush();
 
     /*
-     * TODO: make this faster when nr_slots is big while there are
+     * TODO: make this faster when nr_slots_max is big while there are
      * only a few used slots (small VMs).
      */
     kvm_slots_lock();
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         mem = &kml->slots[i];
         if (mem->memory_size && mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
             kvm_slot_sync_dirty_pages(mem);
@@ -1839,10 +1839,10 @@  void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml,
 {
     int i;
 
-    kml->slots = g_new0(KVMSlot, s->nr_slots);
+    kml->slots = g_new0(KVMSlot, s->nr_slots_max);
     kml->as_id = as_id;
 
-    for (i = 0; i < s->nr_slots; i++) {
+    for (i = 0; i < s->nr_slots_max; i++) {
         kml->slots[i].slot = i;
     }
 
@@ -2454,11 +2454,11 @@  static int kvm_init(MachineState *ms)
         (kvm_supported_memory_attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE);
 
     kvm_immediate_exit = kvm_check_extension(s, KVM_CAP_IMMEDIATE_EXIT);
-    s->nr_slots = kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
+    s->nr_slots_max = kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
 
     /* If unspecified, use the default value */
-    if (!s->nr_slots) {
-        s->nr_slots = 32;
+    if (!s->nr_slots_max) {
+        s->nr_slots_max = 32;
     }
 
     s->nr_as = kvm_check_extension(s, KVM_CAP_MULTI_ADDRESS_SPACE);