Re: [Xen-devel] [PATCH v5 3/3] x86/altp2m: Add a hvmop for querying the suppress #VE bit

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Mon, Sep 3, 2018 at 9:48 AM Adrian Pop <apop@xxxxxxxxxxxxxxx> wrote:
>
> Signed-off-by: Adrian Pop <apop@xxxxxxxxxxxxxxx>

Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>

> ---
>  tools/libxc/include/xenctrl.h   |  2 ++
>  tools/libxc/xc_altp2m.c         | 26 +++++++++++++++++++
>  xen/arch/x86/hvm/hvm.c          | 19 ++++++++++++++
>  xen/arch/x86/mm/mem_access.c    | 45 +++++++++++++++++++++++++++++++++
>  xen/include/public/hvm/hvm_op.h |  2 ++
>  xen/include/xen/mem_access.h    |  3 +++
>  6 files changed, 97 insertions(+)
>
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index cc8b3e7dce..59955f0357 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -1954,6 +1954,8 @@ int xc_altp2m_switch_to_view(xc_interface *handle, 
> uint32_t domid,
>                               uint16_t view_id);
>  int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
>                                uint16_t view_id, xen_pfn_t gfn, bool sve);
> +int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
> +                              uint16_t view_id, xen_pfn_t gfn, bool *sve);
>  int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
>                               uint16_t view_id, xen_pfn_t gfn,
>                               xenmem_access_t access);
> diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
> index f883d0b392..1c9b572e2b 100644
> --- a/tools/libxc/xc_altp2m.c
> +++ b/tools/libxc/xc_altp2m.c
> @@ -163,6 +163,32 @@ int xc_altp2m_switch_to_view(xc_interface *handle, 
> uint32_t domid,
>      return rc;
>  }
>
> +int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
> +                              uint16_t view_id, xen_pfn_t gfn, bool *sve)
> +{
> +    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_get_suppress_ve;
> +    arg->domain = domid;
> +    arg->u.suppress_ve.view = view_id;
> +    arg->u.suppress_ve.gfn = gfn;
> +
> +    rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
> +                  HYPERCALL_BUFFER_AS_ARG(arg));
> +
> +    if ( !rc )
> +        *sve = arg->u.suppress_ve.suppress_ve;
> +
> +    xc_hypercall_buffer_free(handle, arg);
> +    return rc;
> +}
> +
>  int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
>                                uint16_t view_id, xen_pfn_t gfn, bool sve)
>  {
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 64ab36ff53..6f6efb0d8a 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4525,6 +4525,7 @@ static int do_altp2m_op(
>      case HVMOP_altp2m_destroy_p2m:
>      case HVMOP_altp2m_switch_p2m:
>      case HVMOP_altp2m_set_suppress_ve:
> +    case HVMOP_altp2m_get_suppress_ve:
>      case HVMOP_altp2m_set_mem_access:
>      case HVMOP_altp2m_set_mem_access_multi:
>      case HVMOP_altp2m_change_gfn:
> @@ -4655,6 +4656,24 @@ static int do_altp2m_op(
>          }
>          break;
>
> +    case HVMOP_altp2m_get_suppress_ve:
> +        if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
> +            rc = -EINVAL;
> +        else
> +        {
> +            gfn_t gfn = _gfn(a.u.suppress_ve.gfn);
> +            unsigned int altp2m_idx = a.u.suppress_ve.view;
> +            bool suppress_ve;
> +
> +            rc = p2m_get_suppress_ve(d, gfn, &suppress_ve, altp2m_idx);
> +            if ( !rc )
> +            {
> +                a.u.suppress_ve.suppress_ve = suppress_ve;
> +                rc = __copy_to_guest(arg, &a, 1) ? -EFAULT : 0;
> +            }
> +        }
> +        break;
> +
>      case HVMOP_altp2m_set_mem_access:
>          if ( a.u.set_mem_access.pad )
>              rc = -EINVAL;
> diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
> index 4d49025cbe..df78c93cfd 100644
> --- a/xen/arch/x86/mm/mem_access.c
> +++ b/xen/arch/x86/mm/mem_access.c
> @@ -550,6 +550,51 @@ out:
>      return rc;
>  }
>
> +int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
> +                        unsigned int altp2m_idx)
> +{
> +    struct p2m_domain *host_p2m = p2m_get_hostp2m(d);
> +    struct p2m_domain *ap2m = NULL;
> +    struct p2m_domain *p2m;
> +    mfn_t mfn;
> +    p2m_access_t a;
> +    p2m_type_t t;
> +
> +    if ( !cpu_has_vmx_virt_exceptions )
> +        return -EOPNOTSUPP;
> +
> +    /* #VE should be enabled for this vcpu. */
> +    if ( gfn_eq(vcpu_altp2m(current).veinfo_gfn, INVALID_GFN) )
> +        return -ENXIO;
> +
> +    if ( altp2m_idx > 0 )
> +    {
> +        if ( altp2m_idx >= MAX_ALTP2M ||
> +             d->arch.altp2m_eptp[altp2m_idx] == mfn_x(INVALID_MFN) )
> +            return -EINVAL;
> +
> +        p2m = ap2m = d->arch.altp2m_p2m[altp2m_idx];
> +    }
> +    else
> +        p2m = host_p2m;
> +
> +    gfn_lock(host_p2m, gfn, 0);
> +
> +    if ( ap2m )
> +        p2m_lock(ap2m);
> +
> +    mfn = p2m->get_entry(p2m, gfn, &t, &a, 0, NULL, suppress_ve);
> +    if ( !mfn_valid(mfn) )
> +        return -ESRCH;
> +
> +    if ( ap2m )
> +        p2m_unlock(ap2m);
> +
> +    gfn_unlock(host_p2m, gfn, 0);
> +
> +    return 0;
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
> index 14d29d1700..cf00cad164 100644
> --- a/xen/include/public/hvm/hvm_op.h
> +++ b/xen/include/public/hvm/hvm_op.h
> @@ -306,6 +306,8 @@ struct xen_hvm_altp2m_op {
>  #define HVMOP_altp2m_set_mem_access_multi 9
>  /* Set the "Suppress #VE" bit on a page */
>  #define HVMOP_altp2m_set_suppress_ve      10
> +/* Get the "Suppress #VE" bit of a page */
> +#define HVMOP_altp2m_get_suppress_ve      11
>      domid_t domain;
>      uint16_t pad1;
>      uint32_t pad2;
> diff --git a/xen/include/xen/mem_access.h b/xen/include/xen/mem_access.h
> index a8d38b90e6..28cab673da 100644
> --- a/xen/include/xen/mem_access.h
> +++ b/xen/include/xen/mem_access.h
> @@ -75,6 +75,9 @@ long p2m_set_mem_access_multi(struct domain *d,
>  int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, bool suppress_ve,
>                          unsigned int altp2m_idx);
>
> +int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
> +                        unsigned int altp2m_idx);
> +
>  /*
>   * Get access type for a gfn.
>   * If gfn == INVALID_GFN, gets the default access type.
> --
> 2.18.0

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