[PATCH 6/6] tools/arm: exclude iomem from domU extended regions

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

When a device is passed through to a xl domU, the iomem ranges may
overlap with the extended regions. Remove iomem from extended regions.

Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
---
Not sure if we need a Fixes: tag, but if we do:
Fixes: 57f87857dc2d ("libxl/arm: Add handling of extended regions for DomU")
---
 tools/libs/light/libxl_arm.c | 118 +++++++++++++++++++++++++++++------
 1 file changed, 99 insertions(+), 19 deletions(-)

diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
index 75c811053c7c..8ae16a1726fc 100644
--- a/tools/libs/light/libxl_arm.c
+++ b/tools/libs/light/libxl_arm.c
@@ -798,6 +798,8 @@ static int make_timer_node(libxl__gc *gc, void *fdt,
     return 0;
 }
 
+#define MAX_NR_EXT_REGIONS   256
+
 static int make_hypervisor_node(libxl__gc *gc, void *fdt,
                                 const libxl_version_info *vers)
 {
@@ -821,7 +823,7 @@ static int make_hypervisor_node(libxl__gc *gc, void *fdt,
      */
     res = fdt_property_reg_placeholder(gc, fdt, GUEST_ROOT_ADDRESS_CELLS,
                                        GUEST_ROOT_SIZE_CELLS,
-                                       GUEST_RAM_BANKS + 1);
+                                       MAX_NR_EXT_REGIONS + 1);
     if (res) return res;
 
     /*
@@ -1517,17 +1519,29 @@ static void finalise_one_node(libxl__gc *gc, void *fdt, 
const char *uname,
 
 #define EXT_REGION_MIN_SIZE   xen_mk_ullong(0x0004000000) /* 64MB */
 
-static int finalize_hypervisor_node(libxl__gc *gc, struct xc_dom_image *dom)
+static int compare_iomem(const void *a, const void *b)
+{
+    const libxl_iomem_range *x = a, *y = b;
+
+    if (x->gfn < y->gfn)
+        return -1;
+    if (x->gfn > y->gfn)
+        return 1;
+    return 0;
+}
+
+static int finalize_hypervisor_node(libxl__gc *gc,
+                                    libxl_domain_build_info *b_info,
+                                    struct xc_dom_image *dom)
 {
     void *fdt = dom->devicetree_blob;
-    uint64_t region_size[GUEST_RAM_BANKS] = {0}, region_base[GUEST_RAM_BANKS],
-        bankend[GUEST_RAM_BANKS];
+    uint64_t region_base[MAX_NR_EXT_REGIONS], region_size[MAX_NR_EXT_REGIONS];
     uint32_t regs[(GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS) *
-                  (GUEST_RAM_BANKS + 1)];
+                  (MAX_NR_EXT_REGIONS + 1)];
     be32 *cells = &regs[0];
     const uint64_t bankbase[] = GUEST_RAM_BANK_BASES;
     const uint64_t banksize[] = GUEST_RAM_BANK_SIZES;
-    unsigned int i, len, nr_regions = 0;
+    unsigned int i, j, len, nr_regions = 0;
     libxl_dominfo info;
     int offset, rc;
 
@@ -1542,20 +1556,90 @@ static int finalize_hypervisor_node(libxl__gc *gc, 
struct xc_dom_image *dom)
     if (info.gpaddr_bits > 64)
         return ERROR_INVAL;
 
+    qsort(b_info->iomem, b_info->num_iomem, sizeof(libxl_iomem_range),
+          compare_iomem);
+
     /*
      * Try to allocate separate 2MB-aligned extended regions from the first
      * and second RAM banks taking into the account the maximum supported
      * guest physical address space size and the amount of memory assigned
      * to the guest.
      */
-    for (i = 0; i < GUEST_RAM_BANKS; i++) {
-        region_base[i] = bankbase[i] +
+    for (i = 0; i < GUEST_RAM_BANKS && nr_regions < MAX_NR_EXT_REGIONS; i++) {
+        struct {
+            uint64_t start;
+            uint64_t end; /* inclusive */
+        } unallocated;
+        uint64_t size = 0;
+
+        unallocated.start = bankbase[i] +
             ALIGN_UP_TO_2MB((uint64_t)dom->rambank_size[i] << XC_PAGE_SHIFT);
 
-        bankend[i] = ~0ULL >> (64 - info.gpaddr_bits);
-        bankend[i] = min(bankend[i], bankbase[i] + banksize[i] - 1);
-        if (bankend[i] > region_base[i])
-            region_size[i] = bankend[i] - region_base[i] + 1;
+        unallocated.end = ~0ULL >> (64 - info.gpaddr_bits);
+        unallocated.end = min(unallocated.end, bankbase[i] + banksize[i] - 1);
+
+        if (unallocated.end > unallocated.start)
+            size = unallocated.end - unallocated.start + 1;
+
+        if (size < EXT_REGION_MIN_SIZE)
+            continue;
+
+        /* Exclude iomem */
+        for (j = 0; j < b_info->num_iomem && nr_regions < MAX_NR_EXT_REGIONS;
+             j++) {
+            struct {
+                uint64_t start;
+                uint64_t end; /* inclusive */
+            } iomem;
+
+            iomem.start = b_info->iomem[j].gfn << XC_PAGE_SHIFT;
+            iomem.end = ((b_info->iomem[j].gfn + b_info->iomem[j].number)
+                         << XC_PAGE_SHIFT) - 1;
+
+            if (iomem.end >= unallocated.start
+                && iomem.start <= unallocated.end) {
+
+                if (iomem.start <= unallocated.start) {
+                    unallocated.start = iomem.end + 1;
+
+                    if (iomem.end >= unallocated.end)
+                        /* Complete overlap, discard unallocated region */
+                        break;
+
+                    /* Beginning overlap */
+                    continue;
+                }
+
+                if (iomem.start > unallocated.start) {
+                    assert(unallocated.end > unallocated.start);
+                    size = iomem.start - unallocated.start;
+
+                    if (size >= EXT_REGION_MIN_SIZE) {
+                        region_base[nr_regions] = unallocated.start;
+                        region_size[nr_regions] = size;
+                        nr_regions++;
+                    }
+
+                    unallocated.start = iomem.end + 1;
+
+                    if (iomem.end >= unallocated.end)
+                        /* End overlap, discard remaining unallocated region */
+                        break;
+                }
+            }
+        }
+
+        if (unallocated.end > unallocated.start
+            && nr_regions < MAX_NR_EXT_REGIONS)
+        {
+            size = unallocated.end - unallocated.start + 1;
+
+            if (size >= EXT_REGION_MIN_SIZE) {
+                region_base[nr_regions] = unallocated.start;
+                region_size[nr_regions] = size;
+                nr_regions++;
+            }
+        }
     }
 
     /*
@@ -1565,16 +1649,12 @@ static int finalize_hypervisor_node(libxl__gc *gc, 
struct xc_dom_image *dom)
     set_range(&cells, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
               GUEST_GNTTAB_BASE, GUEST_GNTTAB_SIZE);
 
-    for (i = 0; i < GUEST_RAM_BANKS; i++) {
-        if (region_size[i] < EXT_REGION_MIN_SIZE)
-            continue;
-
+    for (i = 0; i < nr_regions; i++) {
         LOG(DEBUG, "Extended region %u: %#"PRIx64"->%#"PRIx64"",
-            nr_regions, region_base[i], region_base[i] + region_size[i]);
+            i, region_base[i], region_base[i] + region_size[i]);
 
         set_range(&cells, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
                   region_base[i], region_size[i]);
-        nr_regions++;
     }
 
     if (!nr_regions)
@@ -1626,7 +1706,7 @@ int libxl__arch_domain_finalise_hw_description(libxl__gc 
*gc,
 
     }
 
-    res = finalize_hypervisor_node(gc, dom);
+    res = finalize_hypervisor_node(gc, &d_config->b_info, dom);
     if (res)
         return res;
 
-- 
2.49.0