[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] hw/mips: malta: Don't boot from flash with KVM
From: |
James Hogan |
Subject: |
Re: [Qemu-devel] [PATCH] hw/mips: malta: Don't boot from flash with KVM T&E |
Date: |
Fri, 20 Jun 2014 14:35:17 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 |
On 20/06/14 14:17, Andreas Färber wrote:
> Hi,
>
> Am 20.06.2014 13:47, schrieb James Hogan:
>> In KVM trap & emulate (T&E) 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 <address@hidden>
>> Signed-off-by: James Hogan <address@hidden>
>> Cc: Paolo Bonzini <address@hidden>
>> ---
>> hw/mips/mips_malta.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>
> Previous commits have used just "mips_malta:", so suggest to do the same
> for consistency - or clean hw/mips/ dir up by renaming the file to just
> malta.c and use "mips/malta:".
>
> http://git.qemu-project.org/?p=qemu.git;a=history;f=hw/mips/mips_malta.c;h=f4a7d47129526f6762eccc47251c8cf3cd27f928;hb=HEAD
Noted
>
> That said,
>
>> diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
>> index 8bc5392b4223..91b0ce566111 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 T&E guest */
>> + if (kvm_enabled()) {
>> + error_report("KVM enabled but no -kernel argument was
>> specified. "
>> + "Booting from flash is not supported with KVM
>> T&E.");
>> + exit(1);
>> + }
>> /* Load firmware from flash. */
>> if (!dinfo) {
>> /* Load a BIOS image. */
>
> Reviewed-by: Andreas Färber <address@hidden>
>
> Are users expected to know/understand "KVM T&E"? You don't test for that
> T&E mode here, so you could either shorten the message to just "KVM" or
> replace the check with a more specific one.
Yeh, not mentioning T&E at all would be better actually. The limitation
is technically a MIPS KVM one rather than being T&E specific.
I'll post a v2.
Thanks for reviewing
James
> Since qtest does not use KVM on MIPS today, exiting without -kernel
> should be fine, but may need updating if we ever get to that.
>
> Regards,
> Andreas
>