Re: [Xen-devel] [PATCH V2] x86/altp2m: add altp2m_vcpu_disable_notify

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 12/18/18 4:54 PM, Razvan Cojocaru wrote:
> Allow altp2m users to disable #VE/VMFUNC alone. Currently it is
> only possible to disable this functionality when we disable altp2m
> completely; #VE/VMFUNC can only be enabled once per altp2m session.
> 
> In addition to making things complete, disabling #VE is also a
> workaround for CFW116 ("When Virtualization Exceptions are Enabled,
> EPT Violations May Generate Erroneous Virtualization Exceptions")
> on Xeon E-2100 CPUs.
> 
> Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
> 
> ---
> Changes since V1:
>  - Updated the patch description to specify E-2100.
>  - Made trying to disable #VE when it's already disabled a no-op.
>  - Removed leftover uint32_t pad; from struct
>    xen_hvm_altp2m_vcpu_disable_notify.
> ---
>  tools/libxc/include/xenctrl.h   |  2 ++
>  tools/libxc/xc_altp2m.c         | 22 ++++++++++++++++++++++
>  xen/arch/x86/hvm/hvm.c          | 29 +++++++++++++++++++++++++++++
>  xen/include/public/hvm/hvm_op.h | 11 ++++++++++-
>  4 files changed, 63 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index 97ae965..31cdda7 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -1932,6 +1932,8 @@ int xc_altp2m_get_domain_state(xc_interface *handle, 
> uint32_t dom, bool *state);
>  int xc_altp2m_set_domain_state(xc_interface *handle, uint32_t dom, bool 
> state);
>  int xc_altp2m_set_vcpu_enable_notify(xc_interface *handle, uint32_t domid,
>                                       uint32_t vcpuid, xen_pfn_t gfn);
> +int xc_altp2m_set_vcpu_disable_notify(xc_interface *handle, uint32_t domid,
> +                                      uint32_t vcpuid);
>  int xc_altp2m_create_view(xc_interface *handle, uint32_t domid,
>                            xenmem_access_t default_access, uint16_t *view_id);
>  int xc_altp2m_destroy_view(xc_interface *handle, uint32_t domid,
> diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
> index 844b9f1..f8cd603 100644
> --- a/tools/libxc/xc_altp2m.c
> +++ b/tools/libxc/xc_altp2m.c
> @@ -91,6 +91,28 @@ int xc_altp2m_set_vcpu_enable_notify(xc_interface *handle, 
> uint32_t domid,
>      return rc;
>  }
>  
> +int xc_altp2m_set_vcpu_disable_notify(xc_interface *handle, uint32_t domid,
> +                                      uint32_t vcpuid)
> +{
> +    int rc;
> +    DECLARE_HYPERCALL_BUFFER(xen_hvm_altp2m_op_t, arg);
> +
> +    arg = xc_hypercall_buffer_alloc(handle, arg, sizeof(*arg));
> +    if ( arg == NULL )
> +        return -1;
> +
> +    arg->version = HVMOP_ALTP2M_INTERFACE_VERSION;
> +    arg->cmd = HVMOP_altp2m_vcpu_disable_notify;
> +    arg->domain = domid;
> +    arg->u.disable_notify.vcpu_id = vcpuid;
> +
> +    rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
> +               HYPERCALL_BUFFER_AS_ARG(arg));
> +
> +    xc_hypercall_buffer_free(handle, arg);
> +    return rc;
> +}
> +
>  int xc_altp2m_create_view(xc_interface *handle, uint32_t domid,
>                            xenmem_access_t default_access, uint16_t *view_id)
>  {
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index d64b6b6..424e4d1 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4485,6 +4485,7 @@ static int do_altp2m_op(
>      case HVMOP_altp2m_get_domain_state:
>      case HVMOP_altp2m_set_domain_state:
>      case HVMOP_altp2m_vcpu_enable_notify:
> +    case HVMOP_altp2m_vcpu_disable_notify:
>      case HVMOP_altp2m_create_p2m:
>      case HVMOP_altp2m_destroy_p2m:
>      case HVMOP_altp2m_switch_p2m:
> @@ -4602,6 +4603,34 @@ static int do_altp2m_op(
>          break;
>      }
>  
> +    case HVMOP_altp2m_vcpu_disable_notify:
> +    {
> +        struct vcpu *v;
> +
> +        if ( a.u.disable_notify.pad ||

Sorry, this should obviously have been removed as well. I'll re-send the
patch.


Thanks,
Razvan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel