Prior to commit f2ce39b4f067 a MachineClass kvm_type method
only needed to be registered to ensure it would be executed.
With commit f2ce39b4f067 a kvm-type machine property must also
be specified. hw/arm/virt relies on the kvm_type method to pass
its selected IPA limit to KVM, but this is not exposed as a
machine property. Restore the previous functionality of invoking
kvm_type when it's present.

Fixes: f2ce39b4f067 ("vl: make qemu_get_machine_opts static")
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 accel/kvm/kvm-all.c | 2 ++
 include/hw/boards.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f88a52393fe0..37b0a1861e72 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2068,6 +2068,8 @@ static int kvm_init(MachineState *ms)
                                                             "kvm-type",
                                                             &error_abort);
         type = mc->kvm_type(ms, kvm_type);
+    } else if (mc->kvm_type) {
+        type = mc->kvm_type(ms, NULL);
     }
 
     do {
diff --git a/include/hw/boards.h b/include/hw/boards.h
index a46dfe5d1a6a..327949967609 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -128,6 +128,7 @@ typedef struct {
  * @kvm_type:
  *    Return the type of KVM corresponding to the kvm-type string option or
  *    computed based on other criteria such as the host kernel capabilities.
+ *    kvm-type may be NULL if it is not needed.
  * @numa_mem_supported:
  *    true if '--numa node.mem' option is supported and false otherwise
  * @smp_parse:
-- 
2.26.2

Hi Drew,

On 3/10/21 2:52 PM, Andrew Jones wrote:
> Prior to commit f2ce39b4f067 a MachineClass kvm_type method
> only needed to be registered to ensure it would be executed.
> With commit f2ce39b4f067 a kvm-type machine property must also
> be specified. hw/arm/virt relies on the kvm_type method to pass
> its selected IPA limit to KVM, but this is not exposed as a
> machine property. Restore the previous functionality of invoking
> kvm_type when it's present.

Ouch, good catch for this regression
> 
> Fixes: f2ce39b4f067 ("vl: make qemu_get_machine_opts static")
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 2 ++
>  include/hw/boards.h | 1 +
>  2 files changed, 3 insertions(+)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index f88a52393fe0..37b0a1861e72 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2068,6 +2068,8 @@ static int kvm_init(MachineState *ms)
>                                                              "kvm-type",
>                                                              &error_abort);
>          type = mc->kvm_type(ms, kvm_type);
> +    } else if (mc->kvm_type) {
> +        type = mc->kvm_type(ms, NULL);
>      }
>  
>      do {
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index a46dfe5d1a6a..327949967609 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -128,6 +128,7 @@ typedef struct {
>   * @kvm_type:
>   *    Return the type of KVM corresponding to the kvm-type string option or
>   *    computed based on other criteria such as the host kernel capabilities.
> + *    kvm-type may be NULL if it is not needed.
>   * @numa_mem_supported:
>   *    true if '--numa node.mem' option is supported and false otherwise
>   * @smp_parse:
> 
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric