Re: [PATCH v3 19/70] i386/tdx: Introduce is_tdx_vm() helper and cache tdx_guest object

[Isaku Yamahata]

On Wed, Nov 15, 2023 at 02:14:28AM -0500,
Xiaoyao Li <xiaoyao.li@intel.com> wrote:

> It will need special handling for TDX VMs all around the QEMU.
> Introduce is_tdx_vm() helper to query if it's a TDX VM.
> 
> Cache tdx_guest object thus no need to cast from ms->cgs every time.
> 
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
> changes in v3:
> - replace object_dynamic_cast with TDX_GUEST();
> ---
>  target/i386/kvm/tdx.c | 15 ++++++++++++++-
>  target/i386/kvm/tdx.h | 10 ++++++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
> index cb0040187b27..cf8889f0a8f9 100644
> --- a/target/i386/kvm/tdx.c
> +++ b/target/i386/kvm/tdx.c
> @@ -21,8 +21,16 @@
>  #include "kvm_i386.h"
>  #include "tdx.h"
>  
> +static TdxGuest *tdx_guest;
> +
>  static struct kvm_tdx_capabilities *tdx_caps;
>  
> +/* It's valid after kvm_confidential_guest_init()->kvm_tdx_init() */
> +bool is_tdx_vm(void)
> +{
> +    return !!tdx_guest;
> +}
> +
>  enum tdx_ioctl_level{
>      TDX_PLATFORM_IOCTL,
>      TDX_VM_IOCTL,
> @@ -114,15 +122,20 @@ static int get_tdx_capabilities(Error **errp)
>  
>  int tdx_kvm_init(MachineState *ms, Error **errp)
>  {
> +    TdxGuest *tdx = TDX_GUEST(OBJECT(ms->cgs));
>      int r = 0;
>  
>      ms->require_guest_memfd = true;
>  
>      if (!tdx_caps) {
>          r = get_tdx_capabilities(errp);
> +        if (r) {
> +            return r;
> +        }
>      }
>  
> -    return r;
> +    tdx_guest = tdx;
> +    return 0;
>  }
>  
>  /* tdx guest */
> diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
> index c8a23d95258d..4036ca2f3f99 100644
> --- a/target/i386/kvm/tdx.h
> +++ b/target/i386/kvm/tdx.h
> @@ -1,6 +1,10 @@
>  #ifndef QEMU_I386_TDX_H
>  #define QEMU_I386_TDX_H
>  
> +#ifndef CONFIG_USER_ONLY
> +#include CONFIG_DEVICES /* CONFIG_TDX */
> +#endif
> +
>  #include "exec/confidential-guest-support.h"
>  
>  #define TYPE_TDX_GUEST "tdx-guest"
> @@ -16,6 +20,12 @@ typedef struct TdxGuest {
>      uint64_t attributes;    /* TD attributes */
>  } TdxGuest;
>  
> +#ifdef CONFIG_TDX
> +bool is_tdx_vm(void);
> +#else
> +#define is_tdx_vm() 0
> +#endif /* CONFIG_TDX */
> +
>  int tdx_kvm_init(MachineState *ms, Error **errp);
>  
>  #endif /* QEMU_I386_TDX_H */
> -- 
> 2.34.1
> 
> 

Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
-- 
Isaku Yamahata <isaku.yamahata@linux.intel.com>