[Qemu-devel] [PATCH v2] mips_malta: Don't boot from flash with KVM

[James Hogan <james.hogan@imgtec.com>]

In KVM mode the flash reset region at 0xbfc00000 isn't executable, which
is why the minimal kernel bootloader is loaded and executed from the
last 1MB of DRAM instead.

Therefore if no kernel is provided on the command line and KVM is
enabled, exit with an error since booting from flash will fail.

Reported-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
---
Changes in v2:
 - Remove mention of T&E. There is currently no distinction since VZ
   isn't supported, and technically the limitation isn't T&E specific.
   (Andreas Färber)
---
 hw/mips/mips_malta.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index 8bc5392b4223..a54ed65a6b73 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -1052,6 +1052,12 @@ void mips_malta_init(MachineState *machine)
                              bootloader_run_addr, kernel_entry);
         }
     } else {
+        /* The flash region isn't executable from a KVM guest */
+        if (kvm_enabled()) {
+            error_report("KVM enabled but no -kernel argument was specified. "
+                         "Booting from flash is not supported with KVM.");
+            exit(1);
+        }
         /* Load firmware from flash. */
         if (!dinfo) {
             /* Load a BIOS image. */
-- 
1.9.3