Re: [PATCH v5 7/8] x86/hvm: Introduce viridian_save_vcpu_ctxt_one() func

[Paul Durrant <Paul.Durrant@citrix.com>]

> -----Original Message-----
> From: Alexandru Isaila [mailto:aisaila@bitdefender.com]
> Sent: 29 May 2018 15:59
> To: xen-devel@lists.xen.org
> Cc: Ian Jackson <Ian.Jackson@citrix.com>; Wei Liu <wei.liu2@citrix.com>;
> jbeulich@suse.com; Andrew Cooper <Andrew.Cooper3@citrix.com>; Paul
> Durrant <Paul.Durrant@citrix.com>; Alexandru Isaila
> <aisaila@bitdefender.com>
> Subject: [PATCH v5 7/8] x86/hvm: Introduce viridian_save_vcpu_ctxt_one()
> func
> 
> This is used to save data from a single instance.
> 
> Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>
> ---
>  xen/arch/x86/hvm/viridian.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
> index 694eae6..d22c8ac 100644
> --- a/xen/arch/x86/hvm/viridian.c
> +++ b/xen/arch/x86/hvm/viridian.c
> @@ -1026,6 +1026,13 @@ static int viridian_load_domain_ctxt(struct domain
> *d, hvm_domain_context_t *h)
>  HVM_REGISTER_SAVE_RESTORE(VIRIDIAN_DOMAIN,
> viridian_save_domain_ctxt,
>                            viridian_load_domain_ctxt, 1, HVMSR_PER_DOM);
> 
> +static void viridian_save_vcpu_ctxt_one(struct vcpu *v, struct
> hvm_viridian_vcpu_context *ctxt)
> +{
> +    ctxt->vp_assist_msr = v->arch.hvm_vcpu.viridian.vp_assist.msr.raw;
> +    ctxt->vp_assist_pending = v->arch.hvm_vcpu.viridian.vp_assist.pending;
> +    *ctxt->_pad = 0;

I'd prefer a memset() to zero the context prior to setting fields. It's more robust if fields (and more padding) are added in future.

  Paul

> +}
> +
>  static int viridian_save_vcpu_ctxt(struct domain *d, hvm_domain_context_t
> *h)
>  {
>      struct vcpu *v;
> @@ -1034,10 +1041,9 @@ static int viridian_save_vcpu_ctxt(struct domain
> *d, hvm_domain_context_t *h)
>          return 0;
> 
>      for_each_vcpu( d, v ) {
> -        struct hvm_viridian_vcpu_context ctxt = {
> -            .vp_assist_msr = v->arch.hvm_vcpu.viridian.vp_assist.msr.raw,
> -            .vp_assist_pending = v->arch.hvm_vcpu.viridian.vp_assist.pending,
> -        };
> +        struct hvm_viridian_vcpu_context ctxt;
> +
> +        viridian_save_vcpu_ctxt_one(v, &ctxt);
> 
>          if ( hvm_save_entry(VIRIDIAN_VCPU, v->vcpu_id, h, &ctxt) != 0 )
>              return 1;
> --
> 2.7.4


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