Re: [PATCH v2 03/11] IOMMU/MMU: enhance the call trees of IOMMU unmapping and mapping

From: "Jan Beulich" <JBeulich@suse.com>
To: Quan Xu <quan.xu@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	"dario.faggioli@citrix.com" <dario.faggioli@citrix.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Jun Nakajima <jun.nakajima@intel.com>
Subject: Re: [PATCH v2 03/11] IOMMU/MMU: enhance the call trees of IOMMU unmapping and mapping
Date: Wed, 27 Apr 2016 08:06:50 -0600	[thread overview]
Message-ID: <5720E39A02000078000E65C3@prv-mh.provo.novell.com> (raw)
In-Reply-To: <945CA011AD5F084CBEA3E851C0AB28894B895B91@SHSMSX101.ccr.corp.intel.com>

>>> On 27.04.16 at 15:10, <quan.xu@intel.com> wrote:
> Then this code is:
> 
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -2467,7 +2467,7 @@ static int __get_page_type(struct page_info *page, unsigned long type,
>                             int preemptible)
>  {
>      unsigned long nx, x, y = page->u.inuse.type_info;
> -    int rc = 0;
> +    int rc = 0, ret = 0;
> 
>      ASSERT(!(type & ~(PGT_type_mask | PGT_pae_xen_l2)));
> 
> @@ -2578,11 +2578,11 @@ static int __get_page_type(struct page_info *page, unsigned long type,
>          if ( d && is_pv_domain(d) && unlikely(need_iommu(d)) )
>          {
>              if ( (x & PGT_type_mask) == PGT_writable_page )
> -                iommu_unmap_page(d, mfn_to_gmfn(d, page_to_mfn(page)));
> +                ret = iommu_unmap_page(d, mfn_to_gmfn(d, page_to_mfn(page)));
>              else if ( type == PGT_writable_page )
> -                iommu_map_page(d, mfn_to_gmfn(d, page_to_mfn(page)),
> -                               page_to_mfn(page),
> -                               IOMMUF_readable|IOMMUF_writable);
> +                ret = iommu_map_page(d, mfn_to_gmfn(d, page_to_mfn(page)),
> +                                     page_to_mfn(page),
> +                                     IOMMUF_readable|IOMMUF_writable);
>          }
>      }
> 
> @@ -2594,6 +2594,9 @@ static int __get_page_type(struct page_info *page, unsigned long type,
>              page->partial_pte = 0;
>          }
>          rc = alloc_page_type(page, type, preemptible);
> +
> +        if ( !rc )
> +            rc = ret;
>      }
> 
>      if ( (x & PGT_partial) && !(nx & PGT_partial) )

Looks okay now.

Jan

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