[Qemu-devel] [PATCH 4/8] exec: Simplify the guest physical memory allocation hook

[Markus Armbruster <armbru@redhat.com>]

Make it a generic hook rather than a KVM hook.  Less code and
ifdeffery.

Since the only user of the hook is old S390 KVM, there's hope we can
get rid of it some day.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 exec.c                  | 20 ++++++++++++++------
 include/exec/exec-all.h |  2 ++
 include/sysemu/kvm.h    |  5 -----
 kvm-all.c               | 13 -------------
 target-s390x/kvm.c      | 17 ++++++-----------
 5 files changed, 22 insertions(+), 35 deletions(-)

diff --git a/exec.c b/exec.c
index 4dbb0f1..c45eb33 100644
--- a/exec.c
+++ b/exec.c
@@ -685,6 +685,19 @@ typedef struct subpage_t {
 static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
                              uint16_t section);
 static subpage_t *subpage_init(hwaddr base);
+
+static void *(*phys_mem_alloc)(ram_addr_t size) = qemu_anon_ram_alloc;
+
+/*
+ * Set a custom physical guest memory alloator.
+ * Accelerators with unusual needs may need this.  Hopefully, we can
+ * get rid of it eventually.
+ */
+void phys_mem_set_alloc(void *(*alloc)(ram_addr_t))
+{
+    phys_mem_alloc = alloc;
+}
+
 static void destroy_page_desc(uint16_t section_index)
 {
     MemoryRegionSection *section = &phys_sections[section_index];
@@ -1098,12 +1111,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
 #endif
         }
         if (!new_block->host) {
-            if (kvm_enabled()) {
-                /* some s390/kvm configurations have special constraints */
-                new_block->host = kvm_ram_alloc(size);
-            } else {
-                new_block->host = qemu_anon_ram_alloc(size);
-            }
+            new_block->host = phys_mem_alloc(size);
             memory_try_enable_merging(new_block->host, size);
         }
     }
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index b2162a4..4921696 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -369,6 +369,8 @@ bool is_tcg_gen_code(uintptr_t pc_ptr);
 
 #if !defined(CONFIG_USER_ONLY)
 
+void phys_mem_set_alloc(void *(*alloc)(ram_addr_t));
+
 struct MemoryRegion *iotlb_to_region(hwaddr index);
 bool io_mem_read(struct MemoryRegion *mr, hwaddr addr,
                  uint64_t *pvalue, unsigned size);
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 8b19322..e722027 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -151,11 +151,6 @@ int kvm_init_vcpu(CPUState *cpu);
 #ifdef NEED_CPU_H
 int kvm_cpu_exec(CPUArchState *env);
 
-#if !defined(CONFIG_USER_ONLY)
-void *kvm_ram_alloc(ram_addr_t size);
-void *kvm_arch_ram_alloc(ram_addr_t size);
-#endif
-
 void kvm_setup_guest_memory(void *start, size_t size);
 void kvm_flush_coalesced_mmio_buffer(void);
 
diff --git a/kvm-all.c b/kvm-all.c
index 405480e..f88c4ec 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1816,19 +1816,6 @@ int kvm_has_intx_set_mask(void)
     return kvm_state->intx_set_mask;
 }
 
-void *kvm_ram_alloc(ram_addr_t size)
-{
-#ifdef TARGET_S390X
-    void *mem;
-
-    mem = kvm_arch_ram_alloc(size);
-    if (mem) {
-        return mem;
-    }
-#endif
-    return qemu_anon_ram_alloc(size);
-}
-
 void kvm_setup_guest_memory(void *start, size_t size)
 {
 #ifdef CONFIG_VALGRIND_H
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 4d9ac4a..e7863d7 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -92,9 +92,15 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
 
 static int cap_sync_regs;
 
+static void *legacy_s390_alloc(ram_addr_t size);
+
 int kvm_arch_init(KVMState *s)
 {
     cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
+    if (!kvm_check_extension(s, KVM_CAP_S390_GMAP)
+        || !kvm_check_extension(s, KVM_CAP_S390_COW)) {
+        phys_mem_set_alloc(legacy_s390_alloc);
+    }
     return 0;
 }
 
@@ -332,17 +338,6 @@ static void *legacy_s390_alloc(ram_addr_t size)
     return mem;
 }
 
-void *kvm_arch_ram_alloc(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(CPUState *cs, struct kvm_sw_breakpoint *bp)
 {
     S390CPU *cpu = S390_CPU(cs);
-- 
1.7.11.7