exec: Simplify the guest physical memory allocation hook

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.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Message-id: 1375276272-15988-5-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <anthony@codemonkey.ws>

exec.c

@@ -749,6 +749,18 @@ static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
                              uint16_t section);
 static subpage_t *subpage_init(AddressSpace *as, 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 uint16_t phys_section_add(MemoryRegionSection *section)
 {
     /* The physical section number is ORed with a page-aligned
@@ -1124,12 +1136,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
 #endif
         }
         if (!new_block->host) {
-            if (kvm_enabled()) {
+            new_block->host = phys_mem_alloc(size);
-                /* some s390/kvm configurations have special constraints */
-                new_block->host = kvm_ram_alloc(size);
-            } else {
-                new_block->host = qemu_anon_ram_alloc(size);
-            }
             memory_try_enable_merging(new_block->host, size);
         }
     }

include/exec/exec-all.h

@@ -368,6 +368,8 @@ static inline uintptr_t tcg_getra_ext(uintptr_t ra)
 
 #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);

include/sysemu/kvm.h

@@ -161,11 +161,6 @@ int kvm_cpu_exec(CPUState *cpu);
 
 #ifdef NEED_CPU_H
 
-#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);
 

kvm-all.c

@@ -1812,19 +1812,6 @@ 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

target-s390x/kvm.c

@@ -93,9 +93,15 @@ 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;
 }
 
@@ -333,17 +339,6 @@ 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)
 {
     static const uint8_t diag_501[] = {0x83, 0x24, 0x05, 0x01};