Re: [PATCH v5 2/7] xen/arm: implement domU extended regions

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

On Fri, Apr 29, 2022 at 11:58 PM Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote:

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

Hello Stefano

[Sorry for the possible format issues]

 

Implement extended regions for dom0less domUs. The implementation is
based on the libxl implementation.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
---
Changes in v5:
- print the domain
- coding style
- simplify the code in find_domU_holes
- return error if no regions allocated in find_domU_holes
- use ROUNDUP
- uint64_t/paddr_t
---
 xen/arch/arm/domain_build.c | 56 +++++++++++++++++++++++++++++++------
 1 file changed, 48 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 8be01678de..34d3e5ce30 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1324,6 +1324,37 @@ out:
     return res;
 }

+static int __init find_domU_holes(const struct kernel_info *kinfo,
+                                  struct meminfo *ext_regions)
+{
+    unsigned int i;
+    paddr_t bankend;
+    const paddr_t bankbase[] = GUEST_RAM_BANK_BASES;
+    const paddr_t banksize[] = GUEST_RAM_BANK_SIZES;
+    int res = -ENOENT;
+
+    for ( i = 0; i < GUEST_RAM_BANKS; i++ )
+    {
+        struct membank *ext_bank = &(ext_regions->bank[ext_regions->nr_banks]);
+
+        ext_bank->start = ROUNDUP(bankbase[i] + kinfo->mem.bank[i].size,
+                                  SZ_2M);
+
+        bankend = ~0ULL >> (64 - p2m_ipa_bits);
+        bankend = min(bankend, bankbase[i] + banksize[i] - 1);
+        if ( bankend > ext_bank->start )
+            ext_bank->size = bankend - ext_bank->start + 1;
+
+        /* 64MB is the minimum size of an extended region */
+        if ( ext_bank->size < MB(64) )
+            continue;
+        ext_regions->nr_banks++;
+        res = 0;
+    }
+
+    return res;
+}
+
 static int __init make_hypervisor_node(struct domain *d,
                                        const struct kernel_info *kinfo,
                                        int addrcells, int sizecells)
@@ -1360,12 +1391,13 @@ static int __init make_hypervisor_node(struct domain *d,

     if ( !opt_ext_regions )

ok, I think, the comment for *opt_ext_regions* at the beginning of this file and the description for *ext_regions* in xen-command-line.pandoc need to be updated,

as they both mention Dom0 only.

 

     {
-        printk(XENLOG_INFO "The extended regions support is disabled\n");
+        printk(XENLOG_INFO "%pd: extended regions support is disabled\n", d);
         nr_ext_regions = 0;
     }
     else if ( is_32bit_domain(d) )
     {
-        printk(XENLOG_WARNING "The extended regions are only supported for 64-bit guest currently\n");
+        printk(XENLOG_WARNING "%pd: extended regions are only supported for 64-bit guest currently\n",
+               d);
         nr_ext_regions = 0;
     }
     else
@@ -1374,13 +1406,21 @@ static int __init make_hypervisor_node(struct domain *d,
         if ( !ext_regions )
             return -ENOMEM;

-        if ( !is_iommu_enabled(d) )
-            res = find_unallocated_memory(kinfo, ext_regions);
+        if ( is_domain_direct_mapped(d) )
+        {
+            if ( !is_iommu_enabled(d) )
+                res = find_unallocated_memory(kinfo, ext_regions);
+            else
+                res = find_memory_holes(kinfo, ext_regions);
+        }
         else
-            res = find_memory_holes(kinfo, ext_regions);
+        {
+            res = find_domU_holes(kinfo, ext_regions);
+        }

         if ( res )
-            printk(XENLOG_WARNING "Failed to allocate extended regions\n");
+            printk(XENLOG_WARNING "%pd: failed to allocate extended regions\n",
+                   d);
         nr_ext_regions = ext_regions->nr_banks;
     }

@@ -1401,8 +1441,8 @@ static int __init make_hypervisor_node(struct domain *d,
         u64 start = ext_regions->bank[i].start;
         u64 size = ext_regions->bank[i].size;

-        printk("Extended region %d: %#"PRIx64"->%#"PRIx64"\n",
-               i, start, start + size);
+        printk("%pd: extended region %d: %#"PRIx64"->%#"PRIx64"\n",
+               d, i, start, start + size);

         dt_child_set_range(&cells, addrcells, sizecells, start, size);
     }
--
2.25.1

--

Regards,

Oleksandr Tyshchenko