Re: [Xen-devel] [PATCH v3 2/2] passthrough/amd: Clean iommu_hap_pt_share enabled code

["Woods, Brian" <Brian.Woods@amd.com>]

On Tue, Jul 16, 2019 at 12:01:15PM +0000, Alexandru Stefan ISAILA wrote:
> At this moment IOMMU pt sharing is disabled by commit [1].
> 
> This patch cleans the unreachable code garded by iommu_hap_pt_share.
> 
> [1] c2ba3db31ef2d9f1e40e7b6c16cf3be3d671d555
> 
> Signed-off-by: Alexandru Isaila <aisaila@bitdefender.com>

Acked-by: Brian Woods <brian.woods@amd.com>

> ---
>  xen/drivers/passthrough/amd/iommu_map.c       | 28 -------------------
>  xen/drivers/passthrough/amd/pci_amd_iommu.c   |  4 ---
>  xen/include/asm-x86/hvm/svm/amd-iommu-proto.h |  3 --
>  3 files changed, 35 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/amd/iommu_map.c b/xen/drivers/passthrough/amd/iommu_map.c
> index cbf00e9e72..90cc7075c2 100644
> --- a/xen/drivers/passthrough/amd/iommu_map.c
> +++ b/xen/drivers/passthrough/amd/iommu_map.c
> @@ -364,9 +364,6 @@ int amd_iommu_map_page(struct domain *d, dfn_t dfn, mfn_t mfn,
>      int rc;
>      unsigned long pt_mfn[7];
>  
> -    if ( iommu_use_hap_pt(d) )
> -        return 0;
> -
>      memset(pt_mfn, 0, sizeof(pt_mfn));
>  
>      spin_lock(&hd->arch.mapping_lock);
> @@ -420,9 +417,6 @@ int amd_iommu_unmap_page(struct domain *d, dfn_t dfn,
>      unsigned long pt_mfn[7];
>      struct domain_iommu *hd = dom_iommu(d);
>  
> -    if ( iommu_use_hap_pt(d) )
> -        return 0;
> -
>      memset(pt_mfn, 0, sizeof(pt_mfn));
>  
>      spin_lock(&hd->arch.mapping_lock);
> @@ -558,28 +552,6 @@ int amd_iommu_reserve_domain_unity_map(struct domain *domain,
>      return rt;
>  }
>  
> -/* Share p2m table with iommu. */
> -void amd_iommu_share_p2m(struct domain *d)
> -{
> -    struct domain_iommu *hd = dom_iommu(d);
> -    struct page_info *p2m_table;
> -    mfn_t pgd_mfn;
> -
> -    pgd_mfn = pagetable_get_mfn(p2m_get_pagetable(p2m_get_hostp2m(d)));
> -    p2m_table = mfn_to_page(pgd_mfn);
> -
> -    if ( hd->arch.root_table != p2m_table )
> -    {
> -        free_amd_iommu_pgtable(hd->arch.root_table);
> -        hd->arch.root_table = p2m_table;
> -
> -        /* When sharing p2m with iommu, paging mode = 4 */
> -        hd->arch.paging_mode = 4;
> -        AMD_IOMMU_DEBUG("Share p2m table with iommu: p2m table = %#lx\n",
> -                        mfn_x(pgd_mfn));
> -    }
> -}
> -
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c b/xen/drivers/passthrough/amd/pci_amd_iommu.c
> index 4afbcd1609..be076210b6 100644
> --- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
> +++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
> @@ -396,9 +396,6 @@ static void deallocate_iommu_page_tables(struct domain *d)
>  {
>      struct domain_iommu *hd = dom_iommu(d);
>  
> -    if ( iommu_use_hap_pt(d) )
> -        return;
> -
>      spin_lock(&hd->arch.mapping_lock);
>      if ( hd->arch.root_table )
>      {
> @@ -566,7 +563,6 @@ static const struct iommu_ops __initconstrel _iommu_ops = {
>      .setup_hpet_msi = amd_setup_hpet_msi,
>      .suspend = amd_iommu_suspend,
>      .resume = amd_iommu_resume,
> -    .share_p2m = amd_iommu_share_p2m,
>      .crash_shutdown = amd_iommu_crash_shutdown,
>      .dump_p2m_table = amd_dump_p2m_table,
>  };
> diff --git a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
> index e0d5d23978..b832f564a7 100644
> --- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
> +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
> @@ -66,9 +66,6 @@ int __must_check amd_iommu_flush_iotlb_pages(struct domain *d, dfn_t dfn,
>                                               unsigned int flush_flags);
>  int __must_check amd_iommu_flush_iotlb_all(struct domain *d);
>  
> -/* Share p2m table with iommu */
> -void amd_iommu_share_p2m(struct domain *d);
> -
>  /* device table functions */
>  int get_dma_requestor_id(uint16_t seg, uint16_t bdf);
>  void amd_iommu_set_intremap_table(struct amd_iommu_dte *dte,
> -- 
> 2.17.1
> 

-- 
Brian Woods

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