From: Michal Privoznik <mprivozn@redhat.com>
Date: Fri, 20 Oct 2023 08:14:39 +0000 (+0200)
Subject: virhostmem: Get total memory on macOS properly
X-Git-Tag: v9.10.0-rc1~99
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69cdb11fba9e6a6a8c2d518111fe7dc44d622bbd;p=thirdparty%2Flibvirt.git

virhostmem: Get total memory on macOS properly

Problem with HW_PHYSMEM sysctl on 64-bit macOS is that it
returns a 32-bit signed value. Thus it overflows. Switching to
HW_MEMSIZE is recommended as it's of an uint_64 type [1].

1: https://github.com/apple-oss-distributions/xnu/blob/xnu-10002.1.13/bsd/sys/sysctl.h

Reported-by: Jaroslav Suchanek <jsuchane@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---

diff --git a/src/util/virhostmem.c b/src/util/virhostmem.c
index 1da2759ac3..a7027af835 100644
--- a/src/util/virhostmem.c
+++ b/src/util/virhostmem.c
@@ -617,7 +617,10 @@ virHostMemGetTotal(void)
     unsigned long long physmem = 0;
     size_t len = sizeof(physmem);
 
-    if (sysctlbyname("hw.physmem", &physmem, &len, NULL, 0) < 0) {
+    /* On macOS hw.physmem is int32_t which doesn't fly with >4GiB of memory.
+     * But hw.memsize is uint64_t. */
+    if (sysctlbyname("hw.memsize", &physmem, &len, NULL, 0) < 0 &&
+        sysctlbyname("hw.physmem", &physmem, &len, NULL, 0) < 0) {
         virReportSystemError(errno, "%s",
                              _("Unable to query memory total"));
         return 0;