From 1e1da7a963007d03a4e0e9a9e0ff17990bb1608d Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 21 Apr 2023 12:42:51 +0200
Subject: check for e820 conflict

Add support to check for overlaps with e820 entries.
In case the 64bit pci io window has conflicts move it down.

The only known case where this happens is AMD processors
with 1TB address space which has some space just below
1TB reserved for HT.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 src/e820map.c    | 15 +++++++++++++++
 src/e820map.h    |  1 +
 src/fw/pciinit.c |  2 ++
 3 files changed, 18 insertions(+)

diff --git a/src/e820map.c b/src/e820map.c
index 39445cf..c761e5e 100644
--- a/src/e820map.c
+++ b/src/e820map.c
@@ -150,3 +150,18 @@ e820_prepboot(void)
 {
     dump_map();
 }
+
+int
+e820_is_used(u64 start, u64 size)
+{
+    int i;
+    for (i=0; i<e820_count; i++) {
+        struct e820entry *e = &e820_list[i];
+        if (start + size <= e->start)
+            continue;
+        if (start >= e->start + e->size)
+            continue;
+        return 1;
+    }
+    return 0;
+}
diff --git a/src/e820map.h b/src/e820map.h
index de8b523..07ce16e 100644
--- a/src/e820map.h
+++ b/src/e820map.h
@@ -18,6 +18,7 @@ struct e820entry {
 void e820_add(u64 start, u64 size, u32 type);
 void e820_remove(u64 start, u64 size);
 void e820_prepboot(void);
+int e820_is_used(u64 start, u64 size);
 
 // e820 map storage
 extern struct e820entry e820_list[];
diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index b52bd1d..c7084f5 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -1140,6 +1140,8 @@ static void pci_bios_map_devices(struct pci_bus *busses)
             if (r64_mem.base < top - size) {
                 r64_mem.base = top - size;
             }
+            if (e820_is_used(r64_mem.base, size))
+                r64_mem.base -= size;
         }
         r64_mem.base = ALIGN(r64_mem.base, align_mem);
         r64_mem.base = ALIGN(r64_mem.base, (1LL<<30));    // 1G hugepage
-- 
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