Cc'ing PCI maintainers On 8/11/20 1:41 PM, P J P wrote: > From: Prasad J Pandit <p...@fedoraproject.org> > > Add spapr msi mmio read method to avoid NULL pointer dereference > issue. > > Reported-by: Lei Sun <slei.cas...@gmail.com> > Acked-by: David Gibson <da...@gibson.dropbear.id.au> > Reviewed-by: Li Qiang <liq...@gmail.com> > Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> > --- > hw/ppc/spapr_pci.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > Update v4: fix multi-line comment and log guest_error > -> https://lists.nongnu.org/archive/html/qemu-devel/2020-07/msg05311.html > > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c > index 363cdb3f7b..53dfd3d8c6 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_GUEST_ERROR, "%s: invalid access\n", __func__); > + return 0; > +} > + > /* > * MSI/MSIX memory region implementation. > * The handler handles both MSI and MSIX. > @@ -755,8 +762,11 @@ 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 */ > - .read = NULL, > + /* > + * .read result is undefined by PCI spec. > + * define .read method to avoid assert failure in memory_region_init_io > + */ > + .read = spapr_msi_read,
Shouldn't this be a read_with_attrs handler returning MEMTX_ERROR instead? Maybe we need another MemTxResult which does not yet exist. > .write = spapr_msi_write, > .endianness = DEVICE_LITTLE_ENDIAN > }; >
