resume: Don't attempt to use generic reboot mechanisms on QEMU
On QEMU it's necessary to manually reset the BIOS memory region
between 0xc0000-0x100000 on a reboot. After this manual memory reset
is completed, it's not valid to use the generic reset mechanisms.
Rename qemu_prep_reset() to qemu_reboot() and change the function to
immediately reboot after the code memcpy.
This fixes a bug that could cause code corruption on reboots - calling
the udelay() function (as invoked by i8042_reboot and/or pci_reboot)
was not valid after the BIOS was memcpy'd.
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/src/fw/shadow.c b/src/fw/shadow.c
index cd02d3a..c80b266 100644
--- a/src/fw/shadow.c
+++ b/src/fw/shadow.c
@@ -167,7 +167,7 @@
}
void
-qemu_prep_reset(void)
+qemu_reboot(void)
{
if (!CONFIG_QEMU || runningOnXen())
return;
@@ -187,4 +187,16 @@
memcpy(hrp + 4, hrp + 4 + BIOS_SRC_OFFSET, cend - (hrp + 4));
barrier();
HaveRunPost = 0;
+ barrier();
+
+ // Request a QEMU system reset. Do the reset in this function as
+ // the BIOS code was overwritten above and not all BIOS
+ // functionality may be available.
+
+ // Attempt PCI style reset
+ outb(0x02, PORT_PCI_REBOOT);
+ outb(0x06, PORT_PCI_REBOOT);
+
+ // Next try triple faulting the CPU to force a reset
+ asm volatile("int3");
}