RE: [PATCH] x86/xen: support priv-mapping in an HVM tools domain

[Paul Durrant]

Apologies... I misformatted this. I will re-send.

  Paul
> -----Original Message-----
> From: Paul Durrant [mailto:paul.durrant@xxxxxxxxxx]
> Sent: 19 October 2017 16:24
> To: x86@xxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> Subject: [PATCH] x86/xen: support priv-mapping in an HVM tools domain
> 
> If the domain has XENFEAT_auto_translated_physmap then use of the PV-
> specific HYPERVISOR_mmu_update hypercall is clearly incorrect.
> 
> This patch adds checks in xen_remap_domain_gfn_array() and
> xen_unmap_domain_gfn_array() which call through to the approprate
> xlate_mmu function if the feature is present. A check is also added
> to xen_remap_domain_gfn_range() to fail with -EOPNOTSUPP since this
> should not be used in an HVM tools domain.
> 
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> ---
> Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Juergen Gross <jgross@xxxxxxxx>
> Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Ingo Molnar <mingo@xxxxxxxxxx>
> "H. Peter Anvin" <hpa@xxxxxxxxx>
> ---
>  arch/x86/xen/mmu.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 3e15345abfe7..d33e7dbe3129 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -172,6 +172,9 @@ int xen_remap_domain_gfn_range(struct
> vm_area_struct *vma,
>  			       pgprot_t prot, unsigned domid,
>  			       struct page **pages)
>  {
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return -EOPNOTSUPP;
> +
>  	return do_remap_gfn(vma, addr, &gfn, nr, NULL, prot, domid,
> pages);
>  }
>  EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
> @@ -182,6 +185,10 @@ int xen_remap_domain_gfn_array(struct
> vm_area_struct *vma,
>  			       int *err_ptr, pgprot_t prot,
>  			       unsigned domid, struct page **pages)
>  {
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return xen_xlate_remap_gfn_array(vma, addr, gfn, nr,
> err_ptr,
> +						 prot, domid, pages);
> +
>  	/* We BUG_ON because it's a programmer error to pass a NULL
> err_ptr,
>  	 * and the consequences later is quite hard to detect what the actual
>  	 * cause of "wrong memory was mapped in".
> @@ -193,9 +200,12 @@
> EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
> 
>  /* Returns: 0 success */
>  int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
> -			       int numpgs, struct page **pages)
> +			       int nr, struct page **pages)
>  {
> -	if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return xen_xlate_unmap_gfn_range(vma, nr, pages);
> +
> +	if (!pages)
>  		return 0;
> 
>  	return -EINVAL;
> --
> 2.11.0