Re: [PATCH 03/26] confidential guest support: Add kvm_init() and kvm_reset() in class

[Philippe Mathieu-Daudé]

Hi Xiaoyao,

On 22/3/24 19:10, Paolo Bonzini wrote:
> From: Xiaoyao Li <xiaoyao.li@intel.com>
>
> Different confidential VMs in different architectures all have the same
> needs to do their specific initialization (and maybe resetting) stuffs
> with KVM. Currently each of them exposes individual *_kvm_init()
> functions and let machine code or kvm code to call it.
>
> To facilitate the introduction of confidential guest technology from
> different x86 vendors, add two virtual functions, kvm_init() and kvm_reset()
> in ConfidentialGuestSupportClass, and expose two helpers functions for
> invodking them.
>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> Message-Id: <20240229060038.606591-1-xiaoyao.li@intel.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   include/exec/confidential-guest-support.h | 34 ++++++++++++++++++++++-
>   1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/include/exec/confidential-guest-support.h 
> b/include/exec/confidential-guest-support.h
> index ba2dd4b5dfc..e5b188cffbf 100644
> --- a/include/exec/confidential-guest-support.h
> +++ b/include/exec/confidential-guest-support.h
> @@ -23,7 +23,10 @@
>   #include "qom/object.h"
>   
>   #define TYPE_CONFIDENTIAL_GUEST_SUPPORT "confidential-guest-support"
> -OBJECT_DECLARE_SIMPLE_TYPE(ConfidentialGuestSupport, 
> CONFIDENTIAL_GUEST_SUPPORT)
> +OBJECT_DECLARE_TYPE(ConfidentialGuestSupport,
> +                    ConfidentialGuestSupportClass,
> +                    CONFIDENTIAL_GUEST_SUPPORT)
> +
>   
>   struct ConfidentialGuestSupport {
>       Object parent;
> @@ -55,8 +58,37 @@ struct ConfidentialGuestSupport {
>   
>   typedef struct ConfidentialGuestSupportClass {
>       ObjectClass parent;
> +
> +    int (*kvm_init)(ConfidentialGuestSupport *cgs, Error **errp);
> +    int (*kvm_reset)(ConfidentialGuestSupport *cgs, Error **errp);

Can we get a docstring indicating what these functions return?
Looking at the next patch, the KVM specific return value doesn't
seem used, so can we return a boolean instead?

>   } ConfidentialGuestSupportClass;

I suppose it will be easy enough to refactor for future other
HW accelerators.

Regards,

Phil.