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Re: [Qemu-devel] [PATCH v2 1/3] boards.h: Define new flag ignore_memory_
From: |
Alistair Francis |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/3] boards.h: Define new flag ignore_memory_transaction_failures |
Date: |
Wed, 6 Sep 2017 16:16:44 -0700 |
On Tue, Sep 5, 2017 at 9:03 AM, Richard Henderson
<address@hidden> wrote:
> On 09/05/2017 08:53 AM, Peter Maydell wrote:
>> Define a new MachineClass field ignore_memory_transaction_failures.
>> If this is flag is true then the CPU will ignore memory transaction
>> failures which should cause the CPU to take an exception due to an
>> access to an unassigned physical address; the transaction will
>> instead return zero (for a read) or be ignored (for a write). This
>> should be set only by legacy board models which rely on the old
>> RAZ/WI behaviour for handling devices that QEMU does not yet model.
>> New board models should instead use "unimplemented-device" for all
>> memory ranges where the guest will attempt to probe for a device that
>> QEMU doesn't implement and a stub device is required.
>>
>> We need this for ARM boards, where we're about to implement support for
>> generating external aborts on memory transaction failures. Too many
>> of our legacy board models rely on the RAZ/WI behaviour and we
>> would break currently working guests when their "probe for device"
>> code provoked an external abort rather than a RAZ.
>>
>> Signed-off-by: Peter Maydell <address@hidden>
>> ---
>> include/hw/boards.h | 11 +++++++++++
>> include/qom/cpu.h | 7 ++++++-
>> qom/cpu.c | 16 ++++++++++++++++
>> 3 files changed, 33 insertions(+), 1 deletion(-)
>
> Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Alistair Francis <address@hidden>
Thanks,
Alistair
>
>
> r~
>