[PATCH v4 16/16] xen/arm: p2m: Rework the interface of apply_p2m_changes and use typesafe

[Julien Grall <julien.grall@arm.com>]

Most of the callers of apply_p2m_changes have a GFN, a MFN and the
number of frame to change in hand.

Rather than asking each caller to convert the frame to an address,
rework the interfaces to pass the GFN, MFN and the number of frame.

Note that it would be possible to do more clean-up in apply_p2m_changes,
but this will be done in a follow-up series.

Signed-off-by: Julien Grall <julien.grall@arm.com>

---
    Changes in v4:
        - Patch added
---
 xen/arch/arm/p2m.c | 62 ++++++++++++++++++++++++------------------------------
 1 file changed, 28 insertions(+), 34 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 3d076de..6366e8f 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -906,25 +906,26 @@ static void update_reference_mapping(struct page_info *page,
 
 static int apply_p2m_changes(struct domain *d,
                      enum p2m_operation op,
-                     paddr_t start_gpaddr,
-                     paddr_t end_gpaddr,
-                     paddr_t maddr,
+                     gfn_t sgfn,
+                     unsigned long nr,
+                     mfn_t smfn,
                      int mattr,
                      uint32_t mask,
                      p2m_type_t t,
                      p2m_access_t a)
 {
+    paddr_t start_gpaddr = pfn_to_paddr(gfn_x(sgfn));
+    paddr_t end_gpaddr = pfn_to_paddr(gfn_x(sgfn) + nr);
+    paddr_t maddr = pfn_to_paddr(mfn_x(smfn));
     int rc, ret;
     struct p2m_domain *p2m = &d->arch.p2m;
     lpae_t *mappings[4] = { NULL, NULL, NULL, NULL };
     struct page_info *pages[4] = { NULL, NULL, NULL, NULL };
-    paddr_t addr, orig_maddr = maddr;
+    paddr_t addr;
     unsigned int level = 0;
     unsigned int cur_root_table = ~0;
     unsigned int cur_offset[4] = { ~0, ~0, ~0, ~0 };
     unsigned int count = 0;
-    const unsigned long sgfn = paddr_to_pfn(start_gpaddr),
-                        egfn = paddr_to_pfn(end_gpaddr);
     const unsigned int preempt_count_limit = (op == MEMACCESS) ? 1 : 0x2000;
     const bool_t preempt = !is_idle_vcpu(current);
     bool_t flush = false;
@@ -986,9 +987,9 @@ static int apply_p2m_changes(struct domain *d,
                  * Preempt setting mem_access permissions as required by XSA-89,
                  * if it's not the last iteration.
                  */
-                uint32_t progress = paddr_to_pfn(addr) - sgfn + 1;
+                uint32_t progress = paddr_to_pfn(addr) - gfn_x(sgfn) + 1;
 
-                if ( (egfn - sgfn) > progress && !(progress & mask) )
+                if ( nr > progress && !(progress & mask) )
                 {
                     rc = progress;
                     goto out;
@@ -1117,8 +1118,9 @@ static int apply_p2m_changes(struct domain *d,
 
     if ( op == INSERT )
     {
-        p2m->max_mapped_gfn = gfn_max(p2m->max_mapped_gfn, _gfn(egfn));
-        p2m->lowest_mapped_gfn = gfn_min(p2m->lowest_mapped_gfn, _gfn(sgfn));
+        p2m->max_mapped_gfn = gfn_max(p2m->max_mapped_gfn,
+                                      gfn_add(sgfn, nr));
+        p2m->lowest_mapped_gfn = gfn_min(p2m->lowest_mapped_gfn, sgfn);
     }
 
     rc = 0;
@@ -1127,7 +1129,7 @@ out:
     if ( flush )
     {
         flush_tlb_domain(d);
-        ret = iommu_iotlb_flush(d, sgfn, egfn - sgfn);
+        ret = iommu_iotlb_flush(d, gfn_x(sgfn), nr);
         if ( !rc )
             rc = ret;
     }
@@ -1146,12 +1148,14 @@ out:
     if ( rc < 0 && ( op == INSERT ) &&
          addr != start_gpaddr )
     {
+        unsigned long gfn = paddr_to_pfn(addr);
+
         BUG_ON(addr == end_gpaddr);
         /*
          * addr keeps the address of the end of the last successfully-inserted
          * mapping.
          */
-        apply_p2m_changes(d, REMOVE, start_gpaddr, addr, orig_maddr,
+        apply_p2m_changes(d, REMOVE, sgfn, gfn - gfn_x(sgfn), smfn,
                           mattr, 0, p2m_invalid, d->arch.p2m.default_access);
     }
 
@@ -1164,10 +1168,7 @@ static inline int p2m_insert_mapping(struct domain *d,
                                      mfn_t mfn,
                                      int mattr, p2m_type_t t)
 {
-    return apply_p2m_changes(d, INSERT,
-                             pfn_to_paddr(gfn_x(start_gfn)),
-                             pfn_to_paddr(gfn_x(start_gfn) + nr),
-                             pfn_to_paddr(mfn_x(mfn)),
+    return apply_p2m_changes(d, INSERT, start_gfn, nr, mfn,
                              mattr, 0, t, d->arch.p2m.default_access);
 }
 
@@ -1176,10 +1177,7 @@ static inline int p2m_remove_mapping(struct domain *d,
                                      unsigned long nr,
                                      mfn_t mfn)
 {
-    return apply_p2m_changes(d, REMOVE,
-                             pfn_to_paddr(gfn_x(start_gfn)),
-                             pfn_to_paddr(gfn_x(start_gfn) + nr),
-                             pfn_to_paddr(mfn_x(mfn)),
+    return apply_p2m_changes(d, REMOVE, start_gfn, nr, mfn,
                              /* arguments below not used when removing mapping */
                              MATTR_MEM, 0, p2m_invalid,
                              d->arch.p2m.default_access);
@@ -1399,13 +1397,13 @@ err:
 int relinquish_p2m_mapping(struct domain *d)
 {
     struct p2m_domain *p2m = &d->arch.p2m;
+    unsigned long nr;
 
-    return apply_p2m_changes(d, RELINQUISH,
-                              pfn_to_paddr(gfn_x(p2m->lowest_mapped_gfn)),
-                              pfn_to_paddr(gfn_x(p2m->max_mapped_gfn)),
-                              pfn_to_paddr(INVALID_MFN),
-                              MATTR_MEM, 0, p2m_invalid,
-                              d->arch.p2m.default_access);
+    nr = gfn_x(p2m->max_mapped_gfn) - gfn_x(p2m->lowest_mapped_gfn);
+
+    return apply_p2m_changes(d, RELINQUISH, p2m->lowest_mapped_gfn, nr,
+                             INVALID_MFN_T, MATTR_MEM, 0, p2m_invalid,
+                             d->arch.p2m.default_access);
 }
 
 int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr)
@@ -1416,10 +1414,7 @@ int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr)
     start = gfn_max(start, p2m->lowest_mapped_gfn);
     end = gfn_min(end, p2m->max_mapped_gfn);
 
-    return apply_p2m_changes(d, CACHEFLUSH,
-                             pfn_to_paddr(gfn_x(start)),
-                             pfn_to_paddr(gfn_x(end)),
-                             pfn_to_paddr(INVALID_MFN),
+    return apply_p2m_changes(d, CACHEFLUSH, start, nr, INVALID_MFN_T,
                              MATTR_MEM, 0, p2m_invalid,
                              d->arch.p2m.default_access);
 }
@@ -1828,10 +1823,9 @@ long p2m_set_mem_access(struct domain *d, gfn_t gfn, uint32_t nr,
         return 0;
     }
 
-    rc = apply_p2m_changes(d, MEMACCESS,
-                           pfn_to_paddr(gfn_x(gfn) + start),
-                           pfn_to_paddr(gfn_x(gfn) + nr),
-                           0, MATTR_MEM, mask, 0, a);
+    rc = apply_p2m_changes(d, MEMACCESS, gfn_add(gfn, start),
+                           (nr - start), _mfn(INVALID_MFN),
+                           MATTR_MEM, mask, 0, a);
     if ( rc < 0 )
         return rc;
     else if ( rc > 0 )
-- 
1.9.1


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