[PATCH 2/2] x86/cpu: Handle GUEST_MAXPHYADDR < HOST_MAXPHYADDR for hosts that don't support it

[Mohammed Gamal]

If the CPU doesn't support GUEST_MAXPHYADDR < HOST_MAXPHYADDR we
let QEMU choose to use the host MAXPHYADDR and print a warning to the
user.

Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
---
 target/i386/cpu.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index b1b311baa2..91c57117ce 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6589,6 +6589,17 @@ static void x86_cpu_realizefn(DeviceState *dev, Error 
**errp)
             uint32_t host_phys_bits = x86_host_phys_bits();
             static bool warned;
 
+           /*
+            * If host doesn't support setting physical bits on the guest,
+            * report it and return
+            */
+           if (cpu->phys_bits < host_phys_bits &&
+               !kvm_has_smaller_maxphyaddr()) {
+               warn_report("Host doesn't support setting smaller phys-bits."
+                           " Using host phys-bits\n");
+               cpu->phys_bits = host_phys_bits;
+           }
+
             /* Print a warning if the user set it to a value that's not the
              * host value.
              */
-- 
2.26.2