Re: [PATCH 6/6] spapr_pci: add spapr msi read method

[Philippe Mathieu-Daudé]

On 6/17/20 7:39 AM, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> Add spapr msi mmio read method to avoid NULL pointer dereference
> issue.
> 
> Reported-by: Lei Sun <slei.casper@gmail.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/ppc/spapr_pci.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 83f1453096..d4193be205 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -52,6 +52,7 @@
>  #include "sysemu/kvm.h"
>  #include "sysemu/hostmem.h"
>  #include "sysemu/numa.h"
> +#include "qemu/log.h"
>  
>  /* Copied from the kernel arch/powerpc/platforms/pseries/msi.c */
>  #define RTAS_QUERY_FN           0
> @@ -738,6 +739,12 @@ static PCIINTxRoute spapr_route_intx_pin_to_irq(void 
> *opaque, int pin)
>      return route;
>  }
>  
> +static uint64_t spapr_msi_read(void *opaque, hwaddr addr, unsigned size)
> +{
> +    qemu_log_mask(LOG_UNIMP, "%s not implemented\n", __func__);
> +    return 0;
> +}
> +
>  /*
>   * MSI/MSIX memory region implementation.
>   * The handler handles both MSI and MSIX.
> @@ -756,7 +763,7 @@ static void spapr_msi_write(void *opaque, hwaddr addr,
>  
>  static const MemoryRegionOps spapr_msi_ops = {
>      /* There is no .read as the read result is undefined by PCI spec */

We probably want to implement .accepts handler instead.

> -    .read = NULL,
> +    .read = spapr_msi_read,
>      .write = spapr_msi_write,
>      .endianness = DEVICE_LITTLE_ENDIAN
>  };
>