Re: [RFC Patch v2 45/45] x86/hvm: Always set pending event injection when loading VMC[BS] state.

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 08/08/14 08:01, Wen Congyang wrote:
> In colo mode, secondary vm is running, so VM_ENTRY_INTR_INFO may
> valid before restoring vmcs. If there is no pending event after
> restoring vm, we should clear it.
>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>
> Also clear pending software exceptions.
> Copy the fix to SVM as well.
>
> Signed-off-by: Tim Deegan <tim@xen.org>
> ---
>  xen/arch/x86/hvm/svm/svm.c | 16 +++++++++-------
>  xen/arch/x86/hvm/vmx/vmx.c | 25 ++++++++++++-------------
>  2 files changed, 21 insertions(+), 20 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
> index 71b8a6a..f7a0cb8 100644
> --- a/xen/arch/x86/hvm/svm/svm.c
> +++ b/xen/arch/x86/hvm/svm/svm.c
> @@ -321,16 +321,18 @@ static int svm_vmcb_restore(struct vcpu *v, struct hvm_hw_cpu *c)
>          vmcb_set_h_cr3(vmcb, pagetable_get_paddr(p2m_get_pagetable(p2m)));
>      }
>  
> -    if ( c->pending_valid ) 
> +    if ( c->pending_valid
> +         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
>      {
>          gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
>                   c->pending_event, c->error_code);
> -
> -        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> -        {
> -            vmcb->eventinj.bytes = c->pending_event;
> -            vmcb->eventinj.fields.errorcode = c->error_code;
> -        }
> +        vmcb->eventinj.bytes = c->pending_event;
> +        vmcb->eventinj.fields.errorcode = c->error_code;
> +    }
> +    else
> +    {
> +        vmcb->eventinj.bytes = 0;
> +        vmcb->eventinj.fields.errorcode = 0;
>      }

vmcb->eventinj.bytes is part of a union which fully covers .fields. 
Explicitly setting errorcode=0 is redundant.

~Andrew

>  
>      vmcb->cleanbits.bytes = 0;
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index fb65c7d..5f143c0 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -509,23 +509,22 @@ static int vmx_vmcs_restore(struct vcpu *v, struct hvm_hw_cpu *c)
>  
>      __vmwrite(GUEST_DR7, c->dr7);
>  
> -    vmx_vmcs_exit(v);
> -
> -    paging_update_paging_modes(v);
> -
> -    if ( c->pending_valid )
> +    if ( c->pending_valid
> +         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
>      {
>          gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
>                   c->pending_event, c->error_code);
> -
> -        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
> -        {
> -            vmx_vmcs_enter(v);
> -            __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
> -            __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
> -            vmx_vmcs_exit(v);
> -        }
> +        __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
> +        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
>      }
> +    else
> +    {
> +        __vmwrite(VM_ENTRY_INTR_INFO, 0);
> +        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, 0);
> +    }
> +    vmx_vmcs_exit(v);
> +
> +    paging_update_paging_modes(v);
>  
>      return 0;
>  }