RE: [PATCH 1/1] xlnx-versal-ospi: disable reentrancy detection for iomem_dac

[Boddu, Sai Pavan]

Hi Peter,

>-----Original Message-----
>From: Peter Maydell <peter.maydell@linaro.org>
>Sent: Tuesday, December 12, 2023 10:12 PM
>To: Boddu, Sai Pavan <sai.pavan.boddu@amd.com>
>Cc: qemu-devel@nongnu.org; qemu-arm@nongnu.org; qemu-
>block@nongnu.org; Alistair Francis <alistair@alistair23.me>; Edgar E. Iglesias
><edgar.iglesias@gmail.com>; Kevin Wolf <kwolf@redhat.com>; Francisco
>Iglesias <frasse.iglesias@gmail.com>; saipavanboddu@gmail.com
>Subject: Re: [PATCH 1/1] xlnx-versal-ospi: disable reentrancy detection for
>iomem_dac
>
>On Tue, 5 Dec 2023 at 10:08, Sai Pavan Boddu <sai.pavan.boddu@amd.com>
>wrote:
>>
>> The OSPI DMA reads flash data through the OSPI linear address space
>> (the iomem_dac region), because of this the reentrancy guard
>> introduced in commit a2e1753b ("memory: prevent dma-reentracy issues")
>> is disabled for the memory region.
>>
>> Signed-off-by: Sai Pavan Boddu <sai.pavan.boddu@amd.com>
>> ---
>>  hw/ssi/xlnx-versal-ospi.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/hw/ssi/xlnx-versal-ospi.c b/hw/ssi/xlnx-versal-ospi.c
>> index 1a61679c2f..5123e7dde7 100644
>> --- a/hw/ssi/xlnx-versal-ospi.c
>> +++ b/hw/ssi/xlnx-versal-ospi.c
>> @@ -1772,6 +1772,7 @@ static void xlnx_versal_ospi_init(Object *obj)
>>      memory_region_init_io(&s->iomem_dac, obj, &ospi_dac_ops, s,
>>                            TYPE_XILINX_VERSAL_OSPI "-dac", 0x20000000);
>>      sysbus_init_mmio(sbd, &s->iomem_dac);
>> +    s->iomem_dac.disable_reentrancy_guard = true;
>
>Where we set this flag we should have a comment explaining why we need to
>do it, please.
[Boddu, Sai Pavan] Sure, I will send a V2 on this.

Regards,
Sai pavan
>
>PS: for a single patch you don't need to use a separate cover letter; cover 
>letters
>are only needed for multi-patch series.
>
>thanks
>-- PMM