Re: shared memory mechanism other than ivshmem

[Sanjeev Kumar]

Hey Gustavo,

Hope you are doing good. I am trying to increase the size of shared memory to 18MB. But i am getting below error.

"qemu-system-aarch64: -device ivshmem-flat,chardev=ivshmem_flat,x-bus-address-iomem=0x400FF000,x-bus-address-shmem=0x40100000,shmem-size=18874368: Can't map shmem fd: shmem size different from device size!"

i started ivshmem-server with below command

sudo ivshmem-server -l 18874368 -F

it is working fine with 8MB (shmem-size=8388608) but with 18MB(shmem-size=18874368), it is failing.

help please.

On Fri, May 17, 2024 at 7:07 PM Gustavo Romero <gustavo.romero@linaro.org> wrote:

Hi Sanjeev,

On 5/17/24 3:02 PM, Sanjeev Kumar wrote:
> Hi Gustavo,
> I understood difference between the two patchsets. thanks for the ivshmem-flat. i will try to get info from QNX side how to access the memory location in QNX. with the ivshmem-flat enabled, i am able to see shmem in "info qtree" as below
> (qemu) info qtree
> bus: main-system-bus
>    type System
>    dev: ivshmem-flat, id ""
>      gpio-out "sysbus-irq" 1
>      chardev = "ivshmem_flat"
>      shmem-size = 4194304 (0x400000)
>      x-irq-qompath = "/machine/unattached/device[4]/gic/unnamed-gpio-in[0]"
>      x-bus-address-iomem = 1074786304 (0x400ff000)
>      x-bus-address-shmem = 1074790400 (0x40100000)
>      mmio 00000000400ff000/0000000000000010
>      mmio 0000000040100000/0000000000400000
>
> now need to explore in guest os(QNX) on how to read this memory location.

It looks like all is set for QNX. Cool.

I'm on vacation for the next two weeks so I'll be slow replying. Good luck!


Cheers,
Gustavo