Re: [Qemu-devel] [PATCH v1 1/2] hw/pvrdma: make DSR mapping idempotent in load_dsr()

[Marcel Apfelbaum <marcel.apfelbaum@gmail.com>]

On 8/28/19 5:23 PM, Sukrit Bhatnagar wrote:
> Map to DSR only when there is no mapping done already i.e., when
> dev->dsr_info.dsr is NULL. This allows the rest of mappings and
> ring inits to be done by calling load_dsr() when DSR has already
> been mapped to, somewhere else.
>
> Move free_dsr() out of load_dsr() and call it before the latter
> as and when needed. This aids the case where load_dsr() is called
> having DSR mapping already done, but the rest of map and init
> operations are pending, and prevents an unmap of the DSR.
>
> Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> Cc: Yuval Shaia <yuval.shaia@oracle.com>
> Signed-off-by: Sukrit Bhatnagar <skrtbhtngr@gmail.com>
> ---
>   hw/rdma/vmw/pvrdma_main.c | 17 +++++++++--------
>   1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
> index adcf79cd63..6c90db96f9 100644
> --- a/hw/rdma/vmw/pvrdma_main.c
> +++ b/hw/rdma/vmw/pvrdma_main.c
> @@ -172,15 +172,15 @@ static int load_dsr(PVRDMADev *dev)
>       DSRInfo *dsr_info;
>       struct pvrdma_device_shared_region *dsr;
>   
> -    free_dsr(dev);
> -
> -    /* Map to DSR */
> -    dev->dsr_info.dsr = rdma_pci_dma_map(pci_dev, dev->dsr_info.dma,
> -                              sizeof(struct pvrdma_device_shared_region));
>       if (!dev->dsr_info.dsr) {
> -        rdma_error_report("Failed to map to DSR");
> -        rc = -ENOMEM;
> -        goto out;
> +        /* Map to DSR */
> +        dev->dsr_info.dsr = rdma_pci_dma_map(pci_dev, dev->dsr_info.dma,
> +                                  sizeof(struct pvrdma_device_shared_region));
> +        if (!dev->dsr_info.dsr) {
> +            rdma_error_report("Failed to map to DSR");
> +            rc = -ENOMEM;
> +            goto out;
> +        }
>       }
>   
>       /* Shortcuts */
> @@ -402,6 +402,7 @@ static void pvrdma_regs_write(void *opaque, hwaddr addr, uint64_t val,
>       case PVRDMA_REG_DSRHIGH:
>           trace_pvrdma_regs_write(addr, val, "DSRHIGH", "");
>           dev->dsr_info.dma |= val << 32;
> +        free_dsr(dev);
>           load_dsr(dev);
>           init_dsr_dev_caps(dev);
>           break;

Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>

Thanks,
Marcel