[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 01/23] AMD/IOMMU: have callers specify the target level for page table walks
In order to be able to insert/remove super-pages we need to allow callers of the walking function to specify at which point to stop the walk. (For now at least gcc will instantiate just a variant of the function with the parameter eliminated, so effectively no change to generated code as far as the parameter addition goes.) Instead of merely adjusting a BUG_ON() condition, convert it into an error return - there's no reason to crash the entire host in that case. Leave an assertion though for spotting issues early in debug builds. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx> --- v3: Add ASSERT_UNREACHABLE(). Adjust a comment. --- a/xen/drivers/passthrough/amd/iommu_map.c +++ b/xen/drivers/passthrough/amd/iommu_map.c @@ -178,7 +178,8 @@ void __init iommu_dte_add_device_entry(s * page tables. */ static int iommu_pde_from_dfn(struct domain *d, unsigned long dfn, - unsigned long *pt_mfn, bool map) + unsigned int target, unsigned long *pt_mfn, + bool map) { union amd_iommu_pte *pde, *next_table_vaddr; unsigned long next_table_mfn; @@ -189,7 +190,11 @@ static int iommu_pde_from_dfn(struct dom table = hd->arch.amd.root_table; level = hd->arch.amd.paging_mode; - BUG_ON( table == NULL || level < 1 || level > 6 ); + if ( !table || target < 1 || level < target || level > 6 ) + { + ASSERT_UNREACHABLE(); + return 1; + } /* * A frame number past what the current page tables can represent can't @@ -200,7 +205,7 @@ static int iommu_pde_from_dfn(struct dom next_table_mfn = mfn_x(page_to_mfn(table)); - while ( level > 1 ) + while ( level > target ) { unsigned int next_level = level - 1; @@ -271,7 +276,7 @@ static int iommu_pde_from_dfn(struct dom level--; } - /* mfn of level 1 page table */ + /* mfn of target level page table */ *pt_mfn = next_table_mfn; return 0; } @@ -307,7 +312,7 @@ int amd_iommu_map_page(struct domain *d, return rc; } - if ( iommu_pde_from_dfn(d, dfn_x(dfn), &pt_mfn, true) || !pt_mfn ) + if ( iommu_pde_from_dfn(d, dfn_x(dfn), 1, &pt_mfn, true) || !pt_mfn ) { spin_unlock(&hd->arch.mapping_lock); AMD_IOMMU_ERROR("invalid IO pagetable entry dfn = %"PRI_dfn"\n", @@ -340,7 +345,7 @@ int amd_iommu_unmap_page(struct domain * return 0; } - if ( iommu_pde_from_dfn(d, dfn_x(dfn), &pt_mfn, false) ) + if ( iommu_pde_from_dfn(d, dfn_x(dfn), 1, &pt_mfn, false) ) { spin_unlock(&hd->arch.mapping_lock); AMD_IOMMU_ERROR("invalid IO pagetable entry dfn = %"PRI_dfn"\n",
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