Re: [PATCH v2 1/5] target/ppc/kvm.c: do not return -1 on uint64_t return

[Cédric Le Goater]

On 7/6/22 21:31, Daniel Henrique Barboza wrote:

kvmppc_read_int_dt() and kvmppc_read_int_cpu_dt() return an uint64_t,
while returning -1 when an error occurs. kvmppc_read_int_cpu_dt() claims
that it will return 0 if anything wrong happens, but it's returning -1
if kmvppc_find_cpu_dt() fails.

The elephant in the room is that returning -1 while claiming that the
return is uint64_t, results in 18446744073709551615 for the callers.
This reason alone is enough to not return -1 under these circunstances.

We'll still have the problem of having to deal with a '0' return that
might, or might not be, an error. We'll make this distintion clear in
the next patches.

Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
---
  target/ppc/kvm.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 6eed466f80..109823136d 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -1907,7 +1907,7 @@ static uint64_t kvmppc_read_int_dt(const char *filename)

I would add an errp parameter and use error_setg_errno().

C.

f = fopen(filename, "rb");

      if (!f) {
-        return -1;
+        return 0;
      }

len = fread(&u, 1, sizeof(u), f);

@@ -1934,7 +1934,7 @@ static uint64_t kvmppc_read_int_cpu_dt(const char 
*propname)
      uint64_t val;

if (kvmppc_find_cpu_dt(buf, sizeof(buf))) {

-        return -1;
+        return 0;
      }

tmp = g_strdup_printf("%s/%s", buf, propname);