[PATCH v3 2/2] kvm: refactor core virtual machine creation into its own function

[PATCH v3 2/2] kvm: refactor core virtual machine creation into its own function

[Ani Sinha]

Refactoring the core logic around KVM_CREATE_VM into its own separate function
so that it can be called from other functions in subsequent patches. There is
no functional change in this patch.

CC: pbonzini@redhat.com
CC: zhao1.liu@intel.com
CC: cfontana@suse.de
CC: qemu-trivial@nongnu.org
Signed-off-by: Ani Sinha <anisinha@redhat.com>
---
 accel/kvm/kvm-all.c | 88 +++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 34 deletions(-)

changelog:
v2: s/fprintf/warn_report as suggested by zhao
v3: s/warn_report/error_report. function names adjusted to conform to
other names. fprintf -> error_report() moved to its own patch.

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 899b5264e3..610b3ead32 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2385,6 +2385,57 @@ uint32_t kvm_dirty_ring_size(void)
     return kvm_state->kvm_dirty_ring_size;
 }
 
+static int kvm_create_vm(MachineState *ms, KVMState *s, int type)
+{
+    int ret;
+
+    do {
+        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
+    } while (ret == -EINTR);
+
+    if (ret < 0) {
+        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
+                    strerror(-ret));
+
+#ifdef TARGET_S390X
+        if (ret == -EINVAL) {
+            error_report("Host kernel setup problem detected. Please verify:");
+            error_report("- for kernels supporting the switch_amode or"
+                        " user_mode parameters, whether");
+            error_report("  user space is running in primary address space");
+            error_report("- for kernels supporting the vm.allocate_pgste "
+                        "sysctl, whether it is enabled");
+        }
+#elif defined(TARGET_PPC)
+        if (ret == -EINVAL) {
+            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
+                        (type == 2) ? "pr" : "hv");
+        }
+#endif
+    }
+
+    return ret;
+}
+
+static int kvm_machine_type(MachineState *ms)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    int type;
+
+    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
+        g_autofree char *kvm_type;
+        kvm_type = object_property_get_str(OBJECT(current_machine),
+                                           "kvm-type",
+                                           &error_abort);
+        type = mc->kvm_type(ms, kvm_type);
+    } else if (mc->kvm_type) {
+        type = mc->kvm_type(ms, NULL);
+    } else {
+        type = kvm_arch_get_default_type(ms);
+    }
+    return type;
+}
+
 static int kvm_init(MachineState *ms)
 {
     MachineClass *mc = MACHINE_GET_CLASS(ms);
@@ -2467,47 +2518,16 @@ static int kvm_init(MachineState *ms)
     }
     s->as = g_new0(struct KVMAs, s->nr_as);
 
-    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
-        g_autofree char *kvm_type = object_property_get_str(OBJECT(current_machine),
-                                                            "kvm-type",
-                                                            &error_abort);
-        type = mc->kvm_type(ms, kvm_type);
-    } else if (mc->kvm_type) {
-        type = mc->kvm_type(ms, NULL);
-    } else {
-        type = kvm_arch_get_default_type(ms);
-    }
-
+    type = kvm_machine_type(ms);
     if (type < 0) {
         ret = -EINVAL;
         goto err;
     }
 
-    do {
-        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
-    } while (ret == -EINTR);
-
+    ret = kvm_create_vm(ms, s, type);
     if (ret < 0) {
-        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
-                    strerror(-ret));
-
-#ifdef TARGET_S390X
-        if (ret == -EINVAL) {
-            error_report("Host kernel setup problem detected. Please verify:");
-            error_report("- for kernels supporting the switch_amode or"
-                        " user_mode parameters, whether");
-            error_report("  user space is running in primary address space");
-            error_report("- for kernels supporting the vm.allocate_pgste "
-                        "sysctl, whether it is enabled");
-        }
-#elif defined(TARGET_PPC)
-        if (ret == -EINVAL) {
-            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
-                        (type == 2) ? "pr" : "hv");
-        }
-#endif
-    }
         goto err;
+    }
 
     s->vmfd = ret;
 
-- 
2.45.2

[PATCH 0/2] Some refactoring

[Ani Sinha]

replace fprintf() with error_report() in kvm_init()
refactor code in kvm_init() to move core vm creation operation to its
own function.

CC: qemu-trivial@nongnu.org
CC: qemu-devel@nongnu.org
CC: zhao1.liu@intel.com
CC: pbonzini@redhat.com


Ani Sinha (2):
  kvm: replace fprintf with error_report() in kvm_init() for error
    conditions
  kvm: refactor core virtual machine creation into its own function

 accel/kvm/kvm-all.c | 106 +++++++++++++++++++++++++-------------------
 1 file changed, 61 insertions(+), 45 deletions(-)

-- 
2.45.2

[PATCH v2 1/2] kvm: replace fprintf with error_report() in kvm_init() for error conditions

[Ani Sinha]

error_report() is more appropriate for error situations. Replace fprintf with
error_report. Cosmetic. No functional change.

CC: qemu-trivial@nongnu.org
CC: zhao1.liu@intel.com
Signed-off-by: Ani Sinha <anisinha@redhat.com>
---
 accel/kvm/kvm-all.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

changelog:
v2: fix a bug.

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 75d11a07b2..ac168b9663 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2427,7 +2427,7 @@ static int kvm_init(MachineState *ms)
     QLIST_INIT(&s->kvm_parked_vcpus);
     s->fd = qemu_open_old(s->device ?: "/dev/kvm", O_RDWR);
     if (s->fd == -1) {
-        fprintf(stderr, "Could not access KVM kernel module: %m\n");
+        error_report("Could not access KVM kernel module: %m");
         ret = -errno;
         goto err;
     }
@@ -2437,13 +2437,13 @@ static int kvm_init(MachineState *ms)
         if (ret >= 0) {
             ret = -EINVAL;
         }
-        fprintf(stderr, "kvm version too old\n");
+        error_report("kvm version too old");
         goto err;
     }
 
     if (ret > KVM_API_VERSION) {
         ret = -EINVAL;
-        fprintf(stderr, "kvm version not supported\n");
+        error_report("kvm version not supported");
         goto err;
     }
 
@@ -2488,26 +2488,22 @@ static int kvm_init(MachineState *ms)
     } while (ret == -EINTR);
 
     if (ret < 0) {
-        fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -ret,
-                strerror(-ret));
+        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
+                    strerror(-ret));
 
 #ifdef TARGET_S390X
         if (ret == -EINVAL) {
-            fprintf(stderr,
-                    "Host kernel setup problem detected. Please verify:\n");
-            fprintf(stderr, "- for kernels supporting the switch_amode or"
-                    " user_mode parameters, whether\n");
-            fprintf(stderr,
-                    "  user space is running in primary address space\n");
-            fprintf(stderr,
-                    "- for kernels supporting the vm.allocate_pgste sysctl, "
-                    "whether it is enabled\n");
+            error_report("Host kernel setup problem detected. Please verify:");
+            error_report("- for kernels supporting the switch_amode or"
+                        " user_mode parameters, whether");
+            error_report("  user space is running in primary address space");
+            error_report("- for kernels supporting the vm.allocate_pgste "
+                        "sysctl, whether it is enabled");
         }
 #elif defined(TARGET_PPC)
         if (ret == -EINVAL) {
-            fprintf(stderr,
-                    "PPC KVM module is not loaded. Try modprobe kvm_%s.\n",
-                    (type == 2) ? "pr" : "hv");
+            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
+                        (type == 2) ? "pr" : "hv");
         }
 #endif
         goto err;
@@ -2526,9 +2522,9 @@ static int kvm_init(MachineState *ms)
                         nc->name, nc->num, soft_vcpus_limit);
 
             if (nc->num > hard_vcpus_limit) {
-                fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
-                        "the maximum cpus supported by KVM (%d)\n",
-                        nc->name, nc->num, hard_vcpus_limit);
+                error_report("Number of %s cpus requested (%d) exceeds "
+                             "the maximum cpus supported by KVM (%d)",
+                             nc->name, nc->num, hard_vcpus_limit);
                 exit(1);
             }
         }
@@ -2542,8 +2538,8 @@ static int kvm_init(MachineState *ms)
     }
     if (missing_cap) {
         ret = -EINVAL;
-        fprintf(stderr, "kvm does not support %s\n%s",
-                missing_cap->name, upgrade_note);
+        error_report("kvm does not support %s", missing_cap->name);
+        error_report("%s", upgrade_note);
         goto err;
     }
 
-- 
2.45.2

[PATCH v3 2/2] kvm: refactor core virtual machine creation into its own function

[Ani Sinha]

Refactoring the core logic around KVM_CREATE_VM into its own separate function
so that it can be called from other functions in subsequent patches. There is
no functional change in this patch.

CC: pbonzini@redhat.com
CC: zhao1.liu@intel.com
CC: cfontana@suse.de
CC: qemu-trivial@nongnu.org
Signed-off-by: Ani Sinha <anisinha@redhat.com>
---
 accel/kvm/kvm-all.c | 86 ++++++++++++++++++++++++++++-----------------
 1 file changed, 53 insertions(+), 33 deletions(-)

changelog:
v2: s/fprintf/warn_report as suggested by zhao
v3: s/warn_report/error_report. function names adjusted to conform to
other names. fprintf -> error_report() moved to its own patch.

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index ac168b9663..610b3ead32 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2385,6 +2385,57 @@ uint32_t kvm_dirty_ring_size(void)
     return kvm_state->kvm_dirty_ring_size;
 }
 
+static int kvm_create_vm(MachineState *ms, KVMState *s, int type)
+{
+    int ret;
+
+    do {
+        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
+    } while (ret == -EINTR);
+
+    if (ret < 0) {
+        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
+                    strerror(-ret));
+
+#ifdef TARGET_S390X
+        if (ret == -EINVAL) {
+            error_report("Host kernel setup problem detected. Please verify:");
+            error_report("- for kernels supporting the switch_amode or"
+                        " user_mode parameters, whether");
+            error_report("  user space is running in primary address space");
+            error_report("- for kernels supporting the vm.allocate_pgste "
+                        "sysctl, whether it is enabled");
+        }
+#elif defined(TARGET_PPC)
+        if (ret == -EINVAL) {
+            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
+                        (type == 2) ? "pr" : "hv");
+        }
+#endif
+    }
+
+    return ret;
+}
+
+static int kvm_machine_type(MachineState *ms)
+{
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    int type;
+
+    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
+        g_autofree char *kvm_type;
+        kvm_type = object_property_get_str(OBJECT(current_machine),
+                                           "kvm-type",
+                                           &error_abort);
+        type = mc->kvm_type(ms, kvm_type);
+    } else if (mc->kvm_type) {
+        type = mc->kvm_type(ms, NULL);
+    } else {
+        type = kvm_arch_get_default_type(ms);
+    }
+    return type;
+}
+
 static int kvm_init(MachineState *ms)
 {
     MachineClass *mc = MACHINE_GET_CLASS(ms);
@@ -2467,45 +2518,14 @@ static int kvm_init(MachineState *ms)
     }
     s->as = g_new0(struct KVMAs, s->nr_as);
 
-    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
-        g_autofree char *kvm_type = object_property_get_str(OBJECT(current_machine),
-                                                            "kvm-type",
-                                                            &error_abort);
-        type = mc->kvm_type(ms, kvm_type);
-    } else if (mc->kvm_type) {
-        type = mc->kvm_type(ms, NULL);
-    } else {
-        type = kvm_arch_get_default_type(ms);
-    }
-
+    type = kvm_machine_type(ms);
     if (type < 0) {
         ret = -EINVAL;
         goto err;
     }
 
-    do {
-        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
-    } while (ret == -EINTR);
-
+    ret = kvm_create_vm(ms, s, type);
     if (ret < 0) {
-        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
-                    strerror(-ret));
-
-#ifdef TARGET_S390X
-        if (ret == -EINVAL) {
-            error_report("Host kernel setup problem detected. Please verify:");
-            error_report("- for kernels supporting the switch_amode or"
-                        " user_mode parameters, whether");
-            error_report("  user space is running in primary address space");
-            error_report("- for kernels supporting the vm.allocate_pgste "
-                        "sysctl, whether it is enabled");
-        }
-#elif defined(TARGET_PPC)
-        if (ret == -EINVAL) {
-            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
-                        (type == 2) ? "pr" : "hv");
-        }
-#endif
         goto err;
     }
 
-- 
2.45.2

Re: [PATCH v3 2/2] kvm: refactor core virtual machine creation into its own function

[Zhao Liu]

On Fri, Aug 09, 2024 at 10:40:54AM +0530, Ani Sinha wrote:
> Date: Fri,  9 Aug 2024 10:40:54 +0530
> From: Ani Sinha <anisinha@redhat.com>
> Subject: [PATCH v3 2/2] kvm: refactor core virtual machine creation into
>  its own function
> X-Mailer: git-send-email 2.45.2
> 
> Refactoring the core logic around KVM_CREATE_VM into its own separate function
> so that it can be called from other functions in subsequent patches. There is
> no functional change in this patch.
> 
> CC: pbonzini@redhat.com
> CC: zhao1.liu@intel.com
> CC: cfontana@suse.de
> CC: qemu-trivial@nongnu.org
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 86 ++++++++++++++++++++++++++++-----------------
>  1 file changed, 53 insertions(+), 33 deletions(-)
> 
> changelog:
> v2: s/fprintf/warn_report as suggested by zhao
> v3: s/warn_report/error_report. function names adjusted to conform to
> other names. fprintf -> error_report() moved to its own patch.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

Re: [PATCH v2 1/2] kvm: replace fprintf with error_report() in kvm_init() for error conditions

[Zhao Liu]

On Fri, Aug 09, 2024 at 10:40:53AM +0530, Ani Sinha wrote:
> Date: Fri,  9 Aug 2024 10:40:53 +0530
> From: Ani Sinha <anisinha@redhat.com>
> Subject: [PATCH v2 1/2] kvm: replace fprintf with error_report() in
>  kvm_init() for error conditions
> X-Mailer: git-send-email 2.45.2
> 
> error_report() is more appropriate for error situations. Replace fprintf with
> error_report. Cosmetic. No functional change.
> 
> CC: qemu-trivial@nongnu.org
> CC: zhao1.liu@intel.com
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 40 ++++++++++++++++++----------------------
>  1 file changed, 18 insertions(+), 22 deletions(-)
> 
> changelog:
> v2: fix a bug.

Generally good to me. Only some nits below, otherwise,

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

>  #ifdef TARGET_S390X
>          if (ret == -EINVAL) {
> -            fprintf(stderr,
> -                    "Host kernel setup problem detected. Please verify:\n");
> -            fprintf(stderr, "- for kernels supporting the switch_amode or"
> -                    " user_mode parameters, whether\n");
> -            fprintf(stderr,
> -                    "  user space is running in primary address space\n");
> -            fprintf(stderr,
> -                    "- for kernels supporting the vm.allocate_pgste sysctl, "
> -                    "whether it is enabled\n");
> +            error_report("Host kernel setup problem detected. Please verify:");

The doc of error_report() said it doesn't want multiple sentences or trailing
punctuation:

"The resulting message should be a single phrase, with no newline or trailing
punctuation."

So I think these extra messages (with complex formatting & content) are
better printed with error_printf() as I suggested in [1].

[1]: https://lore.kernel.org/qemu-devel/ZrWP0fWPNzeAvjja@intel.com/T/#m953afd879eb6279fcdf03cda594c43f1829bdffe

> +            error_report("- for kernels supporting the switch_amode or"
> +                        " user_mode parameters, whether");
> +            error_report("  user space is running in primary address space");
> +            error_report("- for kernels supporting the vm.allocate_pgste "
> +                        "sysctl, whether it is enabled");
>          }
>  #elif defined(TARGET_PPC)
>          if (ret == -EINVAL) {
> -            fprintf(stderr,
> -                    "PPC KVM module is not loaded. Try modprobe kvm_%s.\n",
> -                    (type == 2) ? "pr" : "hv");
> +            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
> +                        (type == 2) ? "pr" : "hv");

Same here. A trailing punctuation. If possible, feel free to refer to
the comment in [1].

>          }
>  #endif

[snip]

> @@ -2542,8 +2538,8 @@ static int kvm_init(MachineState *ms)
>      }
>      if (missing_cap) {
>          ret = -EINVAL;
> -        fprintf(stderr, "kvm does not support %s\n%s",
> -                missing_cap->name, upgrade_note);
> +        error_report("kvm does not support %s", missing_cap->name);
> +        error_report("%s", upgrade_note);

"upgrade_note" string also has the trailing punctuation, and it's
also better to use error_printf() to replace the 2nd error_report().

For this patch, error_report() is already a big step forward, so I think
these few nits doesn't block this patch.

Thank you for your patience.
Zhao

Re: [PATCH v2 1/2] kvm: replace fprintf with error_report() in kvm_init() for error conditions

[Ani Sinha]

On Fri, Aug 9, 2024 at 11:27 AM Zhao Liu <zhao1.liu@intel.com> wrote:
>
> On Fri, Aug 09, 2024 at 10:40:53AM +0530, Ani Sinha wrote:
> > Date: Fri,  9 Aug 2024 10:40:53 +0530
> > From: Ani Sinha <anisinha@redhat.com>
> > Subject: [PATCH v2 1/2] kvm: replace fprintf with error_report() in
> >  kvm_init() for error conditions
> > X-Mailer: git-send-email 2.45.2
> >
> > error_report() is more appropriate for error situations. Replace fprintf with
> > error_report. Cosmetic. No functional change.
> >
> > CC: qemu-trivial@nongnu.org
> > CC: zhao1.liu@intel.com
> > Signed-off-by: Ani Sinha <anisinha@redhat.com>
> > ---
> >  accel/kvm/kvm-all.c | 40 ++++++++++++++++++----------------------
> >  1 file changed, 18 insertions(+), 22 deletions(-)
> >
> > changelog:
> > v2: fix a bug.
>
> Generally good to me. Only some nits below, otherwise,
>
> Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
>
> >  #ifdef TARGET_S390X
> >          if (ret == -EINVAL) {
> > -            fprintf(stderr,
> > -                    "Host kernel setup problem detected. Please verify:\n");
> > -            fprintf(stderr, "- for kernels supporting the switch_amode or"
> > -                    " user_mode parameters, whether\n");
> > -            fprintf(stderr,
> > -                    "  user space is running in primary address space\n");
> > -            fprintf(stderr,
> > -                    "- for kernels supporting the vm.allocate_pgste sysctl, "
> > -                    "whether it is enabled\n");
> > +            error_report("Host kernel setup problem detected. Please verify:");
>
> The doc of error_report() said it doesn't want multiple sentences or trailing
> punctuation:
>
> "The resulting message should be a single phrase, with no newline or trailing
> punctuation."
>
> So I think these extra messages (with complex formatting & content) are
> better printed with error_printf() as I suggested in [1].
>
> [1]: https://lore.kernel.org/qemu-devel/ZrWP0fWPNzeAvjja@intel.com/T/#m953afd879eb6279fcdf03cda594c43f1829bdffe
>
> > +            error_report("- for kernels supporting the switch_amode or"
> > +                        " user_mode parameters, whether");
> > +            error_report("  user space is running in primary address space");
> > +            error_report("- for kernels supporting the vm.allocate_pgste "
> > +                        "sysctl, whether it is enabled");
> >          }
> >  #elif defined(TARGET_PPC)
> >          if (ret == -EINVAL) {
> > -            fprintf(stderr,
> > -                    "PPC KVM module is not loaded. Try modprobe kvm_%s.\n",
> > -                    (type == 2) ? "pr" : "hv");
> > +            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
> > +                        (type == 2) ? "pr" : "hv");
>
> Same here. A trailing punctuation. If possible, feel free to refer to
> the comment in [1].

vreport() adds a training newline, so I think its ok to remove the
training newline and replace with error_report().

>
> >          }
> >  #endif
>
> [snip]
>
> > @@ -2542,8 +2538,8 @@ static int kvm_init(MachineState *ms)
> >      }
> >      if (missing_cap) {
> >          ret = -EINVAL;
> > -        fprintf(stderr, "kvm does not support %s\n%s",
> > -                missing_cap->name, upgrade_note);
> > +        error_report("kvm does not support %s", missing_cap->name);
> > +        error_report("%s", upgrade_note);
>
> "upgrade_note" string also has the trailing punctuation, and it's
> also better to use error_printf() to replace the 2nd error_report().

Yes this looks ugly and I will replace this one with error_printf()

>
> For this patch, error_report() is already a big step forward, so I think
> these few nits doesn't block this patch.

Thanks but I will send another version with your tag added.

>
> Thank you for your patience.
> Zhao
>

Re: [PATCH v3 2/2] kvm: refactor core virtual machine creation into its own function

[Claudio Fontana]

gltm, thanks!

Reviewed-by: Claudio Fontana <cfontana@suse.de>

On 8/9/24 07:10, Ani Sinha wrote:
> Refactoring the core logic around KVM_CREATE_VM into its own separate function
> so that it can be called from other functions in subsequent patches. There is
> no functional change in this patch.
> 
> CC: pbonzini@redhat.com
> CC: zhao1.liu@intel.com
> CC: cfontana@suse.de
> CC: qemu-trivial@nongnu.org
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 86 ++++++++++++++++++++++++++++-----------------
>  1 file changed, 53 insertions(+), 33 deletions(-)
> 
> changelog:
> v2: s/fprintf/warn_report as suggested by zhao
> v3: s/warn_report/error_report. function names adjusted to conform to
> other names. fprintf -> error_report() moved to its own patch.
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index ac168b9663..610b3ead32 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2385,6 +2385,57 @@ uint32_t kvm_dirty_ring_size(void)
>      return kvm_state->kvm_dirty_ring_size;
>  }
>  
> +static int kvm_create_vm(MachineState *ms, KVMState *s, int type)
> +{
> +    int ret;
> +
> +    do {
> +        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
> +    } while (ret == -EINTR);
> +
> +    if (ret < 0) {
> +        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
> +                    strerror(-ret));
> +
> +#ifdef TARGET_S390X
> +        if (ret == -EINVAL) {
> +            error_report("Host kernel setup problem detected. Please verify:");
> +            error_report("- for kernels supporting the switch_amode or"
> +                        " user_mode parameters, whether");
> +            error_report("  user space is running in primary address space");
> +            error_report("- for kernels supporting the vm.allocate_pgste "
> +                        "sysctl, whether it is enabled");
> +        }
> +#elif defined(TARGET_PPC)
> +        if (ret == -EINVAL) {
> +            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
> +                        (type == 2) ? "pr" : "hv");
> +        }
> +#endif
> +    }
> +
> +    return ret;
> +}
> +
> +static int kvm_machine_type(MachineState *ms)
> +{
> +    MachineClass *mc = MACHINE_GET_CLASS(ms);
> +    int type;
> +
> +    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
> +        g_autofree char *kvm_type;
> +        kvm_type = object_property_get_str(OBJECT(current_machine),
> +                                           "kvm-type",
> +                                           &error_abort);
> +        type = mc->kvm_type(ms, kvm_type);
> +    } else if (mc->kvm_type) {
> +        type = mc->kvm_type(ms, NULL);
> +    } else {
> +        type = kvm_arch_get_default_type(ms);
> +    }
> +    return type;
> +}
> +
>  static int kvm_init(MachineState *ms)
>  {
>      MachineClass *mc = MACHINE_GET_CLASS(ms);
> @@ -2467,45 +2518,14 @@ static int kvm_init(MachineState *ms)
>      }
>      s->as = g_new0(struct KVMAs, s->nr_as);
>  
> -    if (object_property_find(OBJECT(current_machine), "kvm-type")) {
> -        g_autofree char *kvm_type = object_property_get_str(OBJECT(current_machine),
> -                                                            "kvm-type",
> -                                                            &error_abort);
> -        type = mc->kvm_type(ms, kvm_type);
> -    } else if (mc->kvm_type) {
> -        type = mc->kvm_type(ms, NULL);
> -    } else {
> -        type = kvm_arch_get_default_type(ms);
> -    }
> -
> +    type = kvm_machine_type(ms);
>      if (type < 0) {
>          ret = -EINVAL;
>          goto err;
>      }
>  
> -    do {
> -        ret = kvm_ioctl(s, KVM_CREATE_VM, type);
> -    } while (ret == -EINTR);
> -
> +    ret = kvm_create_vm(ms, s, type);
>      if (ret < 0) {
> -        error_report("ioctl(KVM_CREATE_VM) failed: %d %s", -ret,
> -                    strerror(-ret));
> -
> -#ifdef TARGET_S390X
> -        if (ret == -EINVAL) {
> -            error_report("Host kernel setup problem detected. Please verify:");
> -            error_report("- for kernels supporting the switch_amode or"
> -                        " user_mode parameters, whether");
> -            error_report("  user space is running in primary address space");
> -            error_report("- for kernels supporting the vm.allocate_pgste "
> -                        "sysctl, whether it is enabled");
> -        }
> -#elif defined(TARGET_PPC)
> -        if (ret == -EINVAL) {
> -            error_report("PPC KVM module is not loaded. Try modprobe kvm_%s.",
> -                        (type == 2) ? "pr" : "hv");
> -        }
> -#endif
>          goto err;
>      }
>