[Qemu-devel] [PATCH v2] kvm-all: drop kvm_setup_guest_memory

[Qemu-devel] [PATCH v2] kvm-all: drop kvm_setup_guest_memory

[Cao jin]

kvm_setup_guest_memory only does "madvise to QEMU_MADV_DONTFORK" and
is only called by ram_block_add, which actually is duplicate code.
Bonus: add simple comment for kvm_has_sync_mmu to make life easier.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
---

v2 changelog:
1. Fix building failure: remove kvm_setup_guest_memory in kvm-stub.c

 exec.c               |  4 +---
 include/sysemu/kvm.h |  1 -
 kvm-all.c            | 15 +--------------
 kvm-stub.c           |  4 ----
 4 files changed, 2 insertions(+), 22 deletions(-)

diff --git a/exec.c b/exec.c
index 80398b0..56383f4 100644
--- a/exec.c
+++ b/exec.c
@@ -1622,10 +1622,8 @@ static void ram_block_add(RAMBlock *new_block, Error **errp)
     if (new_block->host) {
         qemu_ram_setup_dump(new_block->host, new_block->max_length);
         qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_HUGEPAGE);
+        /* MADV_DONTFORK is also needed by KVM in absence of synchronous MMU */
         qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_DONTFORK);
-        if (kvm_enabled()) {
-            kvm_setup_guest_memory(new_block->host, new_block->max_length);
-        }
     }
 }
 
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index c9c2436..4938f65 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -221,7 +221,6 @@ int kvm_destroy_vcpu(CPUState *cpu);
 #ifdef NEED_CPU_H
 #include "cpu.h"
 
-void kvm_setup_guest_memory(void *start, size_t size);
 void kvm_flush_coalesced_mmio_buffer(void);
 
 int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
diff --git a/kvm-all.c b/kvm-all.c
index ebf35b0..8a4382e 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -2148,6 +2148,7 @@ void kvm_device_access(int fd, int group, uint64_t attr,
     }
 }
 
+/* Return 1 on success, 0 on failure */
 int kvm_has_sync_mmu(void)
 {
     return kvm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
@@ -2190,20 +2191,6 @@ int kvm_has_intx_set_mask(void)
     return kvm_state->intx_set_mask;
 }
 
-void kvm_setup_guest_memory(void *start, size_t size)
-{
-    if (!kvm_has_sync_mmu()) {
-        int ret = qemu_madvise(start, size, QEMU_MADV_DONTFORK);
-
-        if (ret) {
-            perror("qemu_madvise");
-            fprintf(stderr,
-                    "Need MADV_DONTFORK in absence of synchronous KVM MMU\n");
-            exit(1);
-        }
-    }
-}
-
 #ifdef KVM_CAP_SET_GUEST_DEBUG
 struct kvm_sw_breakpoint *kvm_find_sw_breakpoint(CPUState *cpu,
                                                  target_ulong pc)
diff --git a/kvm-stub.c b/kvm-stub.c
index 64e23f6..3227127 100644
--- a/kvm-stub.c
+++ b/kvm-stub.c
@@ -73,10 +73,6 @@ int kvm_has_many_ioeventfds(void)
     return 0;
 }
 
-void kvm_setup_guest_memory(void *start, size_t size)
-{
-}
-
 int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
 {
     return -ENOSYS;
-- 
2.1.0