Re: [PATCH v3 1/2] amd/passthrough: Do not leak domain mappings from do_invalidate_dte()

[Suravee Suthikulanit <suravee.suthikulpanit@amd.com>]

On 12/4/2013 11:59 AM, Andrew Cooper wrote:
> Coverity ID: 1135379
>
> As the code stands, the domain mapping will be leaked on each error path.
>
> The mapping can be for a much shorter period of time, and all the relevent
> information can be pulled out at once.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Keir Fraser <keir@xen.org>
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
>
> ---
>
> Changes in v3:
>   * Dont break the pointer arithmatic on gdte
> ---
>   xen/drivers/passthrough/amd/iommu_guest.c |    9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/xen/drivers/passthrough/amd/iommu_guest.c b/xen/drivers/passthrough/amd/iommu_guest.c
> index 952600a..c1fa0ff 100644
> --- a/xen/drivers/passthrough/amd/iommu_guest.c
> +++ b/xen/drivers/passthrough/amd/iommu_guest.c
> @@ -430,6 +430,10 @@ static int do_invalidate_dte(struct domain *d, cmd_entry_t *cmd)
>   
>       gdom_id  = get_domid_from_dte(gdte);
>       gcr3_gfn = get_guest_cr3_from_dte(gdte);
> +    glx      = get_glx_from_dte(gdte);
> +    gv       = get_gv_from_dte(gdte);
> +
> +    unmap_domain_page(gdte);
Shouldn't this be "unmap_domain_page (dte_base)" instead?

>   
>       /* Do not update host dte before gcr3 has been set */
>       if ( gcr3_gfn == 0 )
> @@ -449,11 +453,6 @@ static int do_invalidate_dte(struct domain *d, cmd_entry_t *cmd)
>           return -ENODEV;
>       }
>   
> -    glx = get_glx_from_dte(gdte);
> -    gv = get_gv_from_dte(gdte);
> -
> -    unmap_domain_page(dte_base);
> -
>       /* Setup host device entry */
>       hdom_id = host_domid(d, gdom_id);
>       req_id = get_dma_requestor_id(iommu->seg, mbdf);
Also, the comment saying "/* Read guest dte information */ " should 
probably be moved as well.

Suravee