Symptoms:
- When a Linux virtual machine configured to use EFI firmware is rebooted, the operating system may appear to hang during boot. This is more likely to occur upon a third or subsequent reboot of a virtual machine, and is more likely to occur if the virtual machine is configured with at least several gigabytes of RAM. This problem has been noted to occur with recent patch releases of Red Hat Enterprise Linux 6.x and 7.x.
- If the virtual machine is configured to log to a console (for example, by adding a serial port and configuring the guest kernel to log to the serial port), a message similar to the following will appear in the console log:
WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing ____MB of RAM and the guest OS will panic with a trace similar to the following:
init_memory_mapping: 0000000000000000-00000000000a0000
0000000000 - 00000a0000 page 4k
kernel direct mapping tables up to a0000 @ 8000-b000
PANIC: early exception 0e rip 10:ffffffff8152e5fa error 0 cr2 ffff880001a8fff0
Pid: 0, comm: swapper Not tainted 2.6.32-642.el6.x86_64 #1
Call Trace:
[<ffffffff81046069>] ? native_read_cr2+0x9/0x10
[<ffffffff81c3a19e>] ? early_idt_handler+0x5e/0x71
[<ffffffff8152e5fa>] ? init_memory_mapping+0x3ba/0x6a0
[<ffffffff8152e5cb>] ? init_memory_mapping+0x38b/0x6a0
[<ffffffff81c407c0>] ? setup_arch+0x5e7/0xccb
[<ffffffff8107db7e>] ? vprintk_default+0xe/0x10
[<ffffffff81546f02>] ? printk+0x4f/0x55
[<ffffffff81c3adda>] ? start_kernel+0xdc/0x431
[<ffffffff81c3a33a>] ? x86_64_start_reservations+0x125/0x129
[<ffffffff81c3a453>] ? x86_64_start_kernel+0x115/0x124
RIP init_memory_mapping+0x3ba/0x6a0