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authorRichard Henderson <richard.henderson@linaro.org>2023-03-06 01:26:29 +0300
committerRichard Henderson <richard.henderson@linaro.org>2023-03-28 15:23:10 -0700
commit95059f9c313a7fbd7f22e4cdc1977c0393addc7b (patch)
tree5cbda761db3d946f2dafca04afaab139077596dd /bsd-user
parenta3a67f54f0b4ec98ff2380a792e5bfeebc47d554 (diff)
downloadfocaccia-qemu-95059f9c313a7fbd7f22e4cdc1977c0393addc7b.tar.gz
focaccia-qemu-95059f9c313a7fbd7f22e4cdc1977c0393addc7b.zip
include/exec: Change reserved_va semantics to last byte
Change the semantics to be the last byte of the guest va, rather
than the following byte.  This avoids some overflow conditions.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'bsd-user')
-rw-r--r--bsd-user/main.c10
-rw-r--r--bsd-user/mmap.c4
2 files changed, 5 insertions, 9 deletions
diff --git a/bsd-user/main.c b/bsd-user/main.c
index 89f225dead..babc3b009b 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -68,13 +68,9 @@ bool have_guest_base;
 # if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
 #  if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \
       (TARGET_LONG_BITS == 32 || defined(TARGET_ABI32))
-/*
- * There are a number of places where we assign reserved_va to a variable
- * of type abi_ulong and expect it to fit.  Avoid the last page.
- */
-#   define MAX_RESERVED_VA  (0xfffffffful & TARGET_PAGE_MASK)
+#   define MAX_RESERVED_VA  0xfffffffful
 #  else
-#   define MAX_RESERVED_VA  (1ul << TARGET_VIRT_ADDR_SPACE_BITS)
+#   define MAX_RESERVED_VA  ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
 #  endif
 # else
 #  define MAX_RESERVED_VA  0
@@ -466,7 +462,7 @@ int main(int argc, char **argv)
     envlist_free(envlist);
 
     if (reserved_va) {
-            mmap_next_start = reserved_va;
+        mmap_next_start = reserved_va + 1;
     }
 
     {
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 696057551a..565b9f97ed 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -234,7 +234,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
     size = HOST_PAGE_ALIGN(size) + alignment;
     end_addr = start + size;
     if (end_addr > reserved_va) {
-        end_addr = reserved_va;
+        end_addr = reserved_va + 1;
     }
     addr = end_addr - qemu_host_page_size;
 
@@ -243,7 +243,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
             if (looped) {
                 return (abi_ulong)-1;
             }
-            end_addr = reserved_va;
+            end_addr = reserved_va + 1;
             addr = end_addr - qemu_host_page_size;
             looped = 1;
             continue;