Re: [PATCH] kvm: selftests: avoid type punning

[Thomas Huth]

On 20/05/2019 15.38, Paolo Bonzini wrote:
> Avoid warnings from -Wstrict-aliasing by using memcpy.
> 
> Signed-off-by: Paolo Bonzini 
> ---
>  tools/testing/selftests/kvm/lib/ucall.c| 2 +-
>  tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/lib/ucall.c 
> b/tools/testing/selftests/kvm/lib/ucall.c
> index a2ab38be2f47..b701a01cfcb6 100644
> --- a/tools/testing/selftests/kvm/lib/ucall.c
> +++ b/tools/testing/selftests/kvm/lib/ucall.c
> @@ -142,7 +142,7 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, 
> struct ucall *uc)
>   vm_vaddr_t gva;
>   TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8,
>   "Unexpected ucall exit mmio address access");
> - gva = *(vm_vaddr_t *)run->mmio.data;
> + memcpy(&gva, run->mmio.data, sizeof(gva));
>   memcpy(uc, addr_gva2hva(vm, gva), sizeof(*uc));
>   }
>  
> diff --git a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c 
> b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
> index 61a2163cf9f1..9d62e2c7e024 100644
> --- a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
> @@ -75,7 +75,7 @@ void set_revision_id_for_vmcs12(struct kvm_nested_state 
> *state,
>   u32 vmcs12_revision)
>  {
>   /* Set revision_id in vmcs12 to vmcs12_revision. */
> - *(u32 *)(state->data) = vmcs12_revision;
> + memcpy(state->data, &vmcs12_revision, sizeof(u32));
>  }
>  
>  void set_default_state(struct kvm_nested_state *state)
> 

Reviewed-by: Thomas Huth 

[PATCH] kvm: selftests: avoid type punning

[Paolo Bonzini]

Avoid warnings from -Wstrict-aliasing by using memcpy.

Signed-off-by: Paolo Bonzini 
---
 tools/testing/selftests/kvm/lib/ucall.c| 2 +-
 tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/ucall.c 
b/tools/testing/selftests/kvm/lib/ucall.c
index a2ab38be2f47..b701a01cfcb6 100644
--- a/tools/testing/selftests/kvm/lib/ucall.c
+++ b/tools/testing/selftests/kvm/lib/ucall.c
@@ -142,7 +142,7 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, 
struct ucall *uc)
vm_vaddr_t gva;
TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8,
"Unexpected ucall exit mmio address access");
-   gva = *(vm_vaddr_t *)run->mmio.data;
+   memcpy(&gva, run->mmio.data, sizeof(gva));
memcpy(uc, addr_gva2hva(vm, gva), sizeof(*uc));
}
 
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c 
b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
index 61a2163cf9f1..9d62e2c7e024 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
@@ -75,7 +75,7 @@ void set_revision_id_for_vmcs12(struct kvm_nested_state 
*state,
u32 vmcs12_revision)
 {
/* Set revision_id in vmcs12 to vmcs12_revision. */
-   *(u32 *)(state->data) = vmcs12_revision;
+   memcpy(state->data, &vmcs12_revision, sizeof(u32));
 }
 
 void set_default_state(struct kvm_nested_state *state)
-- 
1.8.3.1