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[xen staging] Revert "IOMMU/x86: perform PV Dom0 mappings in batches"



commit 81a739a99300ea325caedf696741c9814c5318f6
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Jun 10 10:22:00 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jun 10 10:22:00 2022 +0200

    Revert "IOMMU/x86: perform PV Dom0 mappings in batches"
    
    This reverts commit f3185c165d28901c3222becfc8be547263c53745.
    That change require preemption checking to first be in place in
    iommu_{,un}map().
---
 xen/arch/x86/pv/dom0_build.c        | 84 ++++---------------------------------
 xen/drivers/passthrough/x86/iommu.c | 41 +++++-------------
 2 files changed, 17 insertions(+), 108 deletions(-)

diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 04a4ea3c18..e501979a86 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -46,8 +46,7 @@ void __init dom0_update_physmap(bool compat, unsigned long 
pfn,
 static __init void mark_pv_pt_pages_rdonly(struct domain *d,
                                            l4_pgentry_t *l4start,
                                            unsigned long vpt_start,
-                                           unsigned long nr_pt_pages,
-                                           unsigned int *flush_flags)
+                                           unsigned long nr_pt_pages)
 {
     unsigned long count;
     struct page_info *page;
@@ -72,14 +71,6 @@ static __init void mark_pv_pt_pages_rdonly(struct domain *d,
         ASSERT((page->u.inuse.type_info & PGT_type_mask) <= 
PGT_root_page_table);
         ASSERT(!(page->u.inuse.type_info & ~(PGT_type_mask | PGT_pae_xen_l2)));
 
-        /*
-         * Page table pages need to be removed from the IOMMU again in case
-         * iommu_memory_setup() ended up mapping them.
-         */
-        if ( need_iommu_pt_sync(d) &&
-             iommu_unmap(d, _dfn(mfn_x(page_to_mfn(page))), 1, flush_flags) )
-            BUG();
-
         /* Read-only mapping + PGC_allocated + page-table page. */
         page->count_info         = PGC_allocated | 3;
         page->u.inuse.type_info |= PGT_validated | 1;
@@ -116,43 +107,11 @@ static __init void mark_pv_pt_pages_rdonly(struct domain 
*d,
     unmap_domain_page(pl3e);
 }
 
-static void __init iommu_memory_setup(struct domain *d, const char *what,
-                                      struct page_info *page, unsigned long nr,
-                                      unsigned int *flush_flags)
-{
-    int rc;
-    mfn_t mfn = page_to_mfn(page);
-
-    if ( !need_iommu_pt_sync(d) )
-        return;
-
-    rc = iommu_map(d, _dfn(mfn_x(mfn)), mfn, nr,
-                   IOMMUF_readable | IOMMUF_writable, flush_flags);
-    if ( rc )
-    {
-        printk(XENLOG_ERR "pre-mapping %s MFN [%lx,%lx) into IOMMU failed: 
%d\n",
-               what, mfn_x(mfn), mfn_x(mfn) + nr, rc);
-        return;
-    }
-
-    /*
-     * For successfully established IOMMU mappings the type of the page(s)
-     * needs to match (for _get_page_type() to unmap upon type change). Set
-     * the page(s) to writable with no type ref.
-     */
-    for ( ; nr--; ++page )
-    {
-        ASSERT(!page->u.inuse.type_info);
-        page->u.inuse.type_info = PGT_writable_page | PGT_validated;
-    }
-}
-
 static __init void setup_pv_physmap(struct domain *d, unsigned long pgtbl_pfn,
                                     unsigned long v_start, unsigned long v_end,
                                     unsigned long vphysmap_start,
                                     unsigned long vphysmap_end,
-                                    unsigned long nr_pages,
-                                    unsigned int *flush_flags)
+                                    unsigned long nr_pages)
 {
     struct page_info *page = NULL;
     l4_pgentry_t *pl4e, *l4start = map_domain_page(_mfn(pgtbl_pfn));
@@ -218,10 +177,6 @@ static __init void setup_pv_physmap(struct domain *d, 
unsigned long pgtbl_pfn,
                                              L3_PAGETABLE_SHIFT - PAGE_SHIFT,
                                              MEMF_no_scrub)) != NULL )
             {
-                iommu_memory_setup(d, "P2M 1G", page,
-                                   SUPERPAGE_PAGES * SUPERPAGE_PAGES,
-                                   flush_flags);
-
                 *pl3e = l3e_from_page(page, L1_PROT|_PAGE_DIRTY|_PAGE_PSE);
                 vphysmap_start += 1UL << L3_PAGETABLE_SHIFT;
                 continue;
@@ -248,9 +203,6 @@ static __init void setup_pv_physmap(struct domain *d, 
unsigned long pgtbl_pfn,
                                              L2_PAGETABLE_SHIFT - PAGE_SHIFT,
                                              MEMF_no_scrub)) != NULL )
             {
-                iommu_memory_setup(d, "P2M 2M", page, SUPERPAGE_PAGES,
-                                   flush_flags);
-
                 *pl2e = l2e_from_page(page, L1_PROT|_PAGE_DIRTY|_PAGE_PSE);
                 vphysmap_start += 1UL << L2_PAGETABLE_SHIFT;
                 continue;
@@ -359,7 +311,6 @@ int __init dom0_construct_pv(struct domain *d,
     unsigned long initrd_pfn = -1, initrd_mfn = 0;
     unsigned long count;
     struct page_info *page = NULL;
-    unsigned int flush_flags = 0;
     start_info_t *si;
     struct vcpu *v = d->vcpu[0];
     void *image_base = bootstrap_map(image);
@@ -622,9 +573,6 @@ int __init dom0_construct_pv(struct domain *d,
                     BUG();
         }
         initrd->mod_end = 0;
-
-        iommu_memory_setup(d, "initrd", mfn_to_page(_mfn(initrd_mfn)),
-                           PFN_UP(initrd_len), &flush_flags);
     }
 
     printk("PHYSICAL MEMORY ARRANGEMENT:\n"
@@ -658,13 +606,6 @@ int __init dom0_construct_pv(struct domain *d,
 
     process_pending_softirqs();
 
-    /*
-     * Map the full range here and then punch holes for page tables
-     * alongside marking them as such in mark_pv_pt_pages_rdonly().
-     */
-    iommu_memory_setup(d, "init-alloc", mfn_to_page(_mfn(alloc_spfn)),
-                       alloc_epfn - alloc_spfn, &flush_flags);
-
     mpt_alloc = (vpt_start - v_start) + pfn_to_paddr(alloc_spfn);
     if ( vinitrd_start )
         mpt_alloc -= PAGE_ALIGN(initrd_len);
@@ -749,8 +690,7 @@ int __init dom0_construct_pv(struct domain *d,
         l1tab++;
 
         page = mfn_to_page(_mfn(mfn));
-        if ( (!page->u.inuse.type_info ||
-              page->u.inuse.type_info == (PGT_writable_page | PGT_validated)) 
&&
+        if ( !page->u.inuse.type_info &&
              !get_page_and_type(page, d, PGT_writable_page) )
             BUG();
     }
@@ -779,7 +719,7 @@ int __init dom0_construct_pv(struct domain *d,
     }
 
     /* Pages that are part of page tables must be read only. */
-    mark_pv_pt_pages_rdonly(d, l4start, vpt_start, nr_pt_pages, &flush_flags);
+    mark_pv_pt_pages_rdonly(d, l4start, vpt_start, nr_pt_pages);
 
     /* Mask all upcalls... */
     for ( i = 0; i < XEN_LEGACY_MAX_VCPUS; i++ )
@@ -854,7 +794,7 @@ int __init dom0_construct_pv(struct domain *d,
     {
         pfn = pagetable_get_pfn(v->arch.guest_table);
         setup_pv_physmap(d, pfn, v_start, v_end, vphysmap_start, vphysmap_end,
-                         nr_pages, &flush_flags);
+                         nr_pages);
     }
 
     /* Write the phys->machine and machine->phys table entries. */
@@ -885,9 +825,7 @@ int __init dom0_construct_pv(struct domain *d,
         if ( get_gpfn_from_mfn(mfn) >= count )
         {
             BUG_ON(compat);
-            if ( (!page->u.inuse.type_info ||
-                  page->u.inuse.type_info == (PGT_writable_page |
-                                              PGT_validated)) &&
+            if ( !page->u.inuse.type_info &&
                  !get_page_and_type(page, d, PGT_writable_page) )
                 BUG();
 
@@ -903,12 +841,8 @@ int __init dom0_construct_pv(struct domain *d,
 #endif
     while ( pfn < nr_pages )
     {
-        count = domain_tot_pages(d);
-        if ( (page = alloc_chunk(d, nr_pages - count)) == NULL )
+        if ( (page = alloc_chunk(d, nr_pages - domain_tot_pages(d))) == NULL )
             panic("Not enough RAM for DOM0 reservation\n");
-
-        iommu_memory_setup(d, "chunk", page, domain_tot_pages(d) - count,
-                           &flush_flags);
         while ( pfn < domain_tot_pages(d) )
         {
             mfn = mfn_x(page_to_mfn(page));
@@ -923,10 +857,6 @@ int __init dom0_construct_pv(struct domain *d,
         }
     }
 
-    /* Use while() to avoid compiler warning. */
-    while ( iommu_iotlb_flush_all(d, flush_flags) )
-        break;
-
     if ( initrd_len != 0 )
     {
         si->mod_start = vinitrd_start ?: initrd_pfn;
diff --git a/xen/drivers/passthrough/x86/iommu.c 
b/xen/drivers/passthrough/x86/iommu.c
index 11a4f244e4..0ba95473c9 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -348,8 +348,8 @@ static unsigned int __hwdom_init hwdom_iommu_map(const 
struct domain *d,
 
 void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
 {
-    unsigned long i, top, max_pfn, start, count;
-    unsigned int flush_flags = 0, start_perms = 0;
+    unsigned long i, top, max_pfn;
+    unsigned int flush_flags = 0;
 
     BUG_ON(!is_hardware_domain(d));
 
@@ -380,9 +380,9 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
      * First Mb will get mapped in one go by pvh_populate_p2m(). Avoid
      * setting up potentially conflicting mappings here.
      */
-    start = paging_mode_translate(d) ? PFN_DOWN(MB(1)) : 0;
+    i = paging_mode_translate(d) ? PFN_DOWN(MB(1)) : 0;
 
-    for ( i = start, count = 0; i < top; )
+    for ( ; i < top; i++ )
     {
         unsigned long pfn = pdx_to_pfn(i);
         unsigned int perms = hwdom_iommu_map(d, pfn, max_pfn);
@@ -391,41 +391,20 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
         if ( !perms )
             rc = 0;
         else if ( paging_mode_translate(d) )
-        {
             rc = p2m_add_identity_entry(d, pfn,
                                         perms & IOMMUF_writable ? p2m_access_rw
                                                                 : p2m_access_r,
                                         0);
-            if ( rc )
-                printk(XENLOG_WARNING
-                       "%pd: identity mapping of %lx failed: %d\n",
-                       d, pfn, rc);
-        }
-        else if ( pfn != start + count || perms != start_perms )
-        {
-        commit:
-            rc = iommu_map(d, _dfn(start), _mfn(start), count, start_perms,
-                           &flush_flags);
-            if ( rc )
-                printk(XENLOG_WARNING
-                       "%pd: IOMMU identity mapping of [%lx,%lx) failed: %d\n",
-                       d, pfn, pfn + count, rc);
-            SWAP(start, pfn);
-            start_perms = perms;
-            count = 1;
-        }
         else
-        {
-            ++count;
-            rc = 0;
-        }
+            rc = iommu_map(d, _dfn(pfn), _mfn(pfn), 1ul << PAGE_ORDER_4K,
+                           perms, &flush_flags);
 
+        if ( rc )
+            printk(XENLOG_WARNING "%pd: identity %smapping of %lx failed: 
%d\n",
+                   d, !paging_mode_translate(d) ? "IOMMU " : "", pfn, rc);
 
-        if ( !(++i & 0xfffff) )
+        if (!(i & 0xfffff))
             process_pending_softirqs();
-
-        if ( i == top && count )
-            goto commit;
     }
 
     /* Use if to avoid compiler warning */
--
generated by git-patchbot for /home/xen/git/xen.git#staging



 


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