Re: [PATCH v4 1/8] hw/pci/pci_host: Allow bypass iommu for pci host

[Xingang Wang]

Hi Eric,

On 2021/6/2 20:18, Eric Auger wrote:
> Hi Xingang,
>
> On 5/25/21 5:49 AM, Wang Xingang wrote:
> > From: Xingang Wang <wangxingang5@huawei.com>
> >
> > This add a bypass_iommu property for pci host, which indicates
> > whether devices attached to the pci root bus will bypass iommu.
> > In pci_device_iommu_address_space(), add a bypass_iommu check
> > to avoid getting iommu address space for devices bypass iommu.
> >
> > Signed-off-by: Xingang Wang <wangxingang5@huawei.com>
> > ---
> >   hw/pci/pci.c              | 18 +++++++++++++++++-
> >   hw/pci/pci_host.c         |  2 ++
> >   include/hw/pci/pci.h      |  1 +
> >   include/hw/pci/pci_host.h |  1 +
> >   4 files changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > index 377084f1a8..27d588e268 100644
> > --- a/hw/pci/pci.c
> > +++ b/hw/pci/pci.c
> > @@ -416,6 +416,22 @@ const char *pci_root_bus_path(PCIDevice *dev)
> >       return rootbus->qbus.name;
> >   }
> >   
> > +bool pci_bus_bypass_iommu(PCIBus *bus)
> > +{
> > +    PCIBus *rootbus = bus;
> > +    PCIHostState *host_bridge;
> > +
> > +    if (!pci_bus_is_root(bus)) {
> > +        rootbus = pci_device_root_bus(bus->parent_dev);
> > +    }
> > +
> > +    host_bridge = PCI_HOST_BRIDGE(rootbus->qbus.parent);
> > +
> > +    assert(host_bridge->bus == rootbus);
> > +
> > +    return host_bridge->bypass_iommu;
> > +}
> > +
> >   static void pci_root_bus_init(PCIBus *bus, DeviceState *parent,
> >                                 MemoryRegion *address_space_mem,
> >                                 MemoryRegion *address_space_io,
> > @@ -2718,7 +2734,7 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice 
> > *dev)
> >   
> >           iommu_bus = parent_bus;
> >       }
> > -    if (iommu_bus && iommu_bus->iommu_fn) {
> > +    if (!pci_bus_bypass_iommu(bus) && iommu_bus && iommu_bus->iommu_fn) {
> >           return iommu_bus->iommu_fn(bus, iommu_bus->iommu_opaque, devfn);
> >       }
> >       return &address_space_memory;
> > diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
> > index 8ca5fadcbd..2768db53e6 100644
> > --- a/hw/pci/pci_host.c
> > +++ b/hw/pci/pci_host.c
> > @@ -222,6 +222,8 @@ const VMStateDescription vmstate_pcihost = {
> >   static Property pci_host_properties_common[] = {
> >       DEFINE_PROP_BOOL("x-config-reg-migration-enabled", PCIHostState,
> >                        mig_enabled, true),
> > +    DEFINE_PROP_BOOL("pci-host-bypass-iommu", PCIHostState,
> > +                     bypass_iommu, false),
> "bypass-iommu" may be sufficient.

Thanks, will fix this.

> Besides:
>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Thanks
>
> Eric
>
> >       DEFINE_PROP_END_OF_LIST(),
> >   };
> >   
> > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> > index 6be4e0c460..f4d51b672b 100644
> > --- a/include/hw/pci/pci.h
> > +++ b/include/hw/pci/pci.h
> > @@ -480,6 +480,7 @@ void pci_for_each_bus(PCIBus *bus,
> >   
> >   PCIBus *pci_device_root_bus(const PCIDevice *d);
> >   const char *pci_root_bus_path(PCIDevice *dev);
> > +bool pci_bus_bypass_iommu(PCIBus *bus);
> >   PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn);
> >   int pci_qdev_find_device(const char *id, PCIDevice **pdev);
> >   void pci_bus_get_w64_range(PCIBus *bus, Range *range);
> > diff --git a/include/hw/pci/pci_host.h b/include/hw/pci/pci_host.h
> > index 52e038c019..c6f4eb4585 100644
> > --- a/include/hw/pci/pci_host.h
> > +++ b/include/hw/pci/pci_host.h
> > @@ -43,6 +43,7 @@ struct PCIHostState {
> >       uint32_t config_reg;
> >       bool mig_enabled;
> >       PCIBus *bus;
> > +    bool bypass_iommu;
> >   
> >       QLIST_ENTRY(PCIHostState) next;
> >   };
>
> .