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Re: [Qemu-devel] [PATCH 1/2] pcie_root_port: Allow ACS to be disabled
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] pcie_root_port: Allow ACS to be disabled |
Date: |
Tue, 30 Jul 2019 13:41:41 +0100 |
User-agent: |
Mutt/1.12.0 (2019-05-25) |
* Igor Mammedov (address@hidden) wrote:
> On Tue, 30 Jul 2019 12:13:06 +0100
> "Dr. David Alan Gilbert" <address@hidden> wrote:
>
> > * Igor Mammedov (address@hidden) wrote:
> > > On Tue, 30 Jul 2019 10:37:18 +0100
> > > "Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> > >
> > > > From: "Dr. David Alan Gilbert" <address@hidden>
> > > >
> > > > ACS was added in 4.0 unconditionally, this breaks migration
> > > > compatibility.
> > > > Allow ACS to be disabled by adding a property that's
> > > > checked by pcie_root_port.
> > > >
> > > > Unfortunately pcie-root-port doesn't have any instance data,
> > > > so there's no where for that flag to live, so stuff it into
> > > > PCIESlot.
> > > >
> > > > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > > > ---
> > > > hw/pci-bridge/pcie_root_port.c | 3 ++-
> > > > include/hw/pci/pcie_port.h | 2 ++
> > > > 2 files changed, 4 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/hw/pci-bridge/pcie_root_port.c
> > > > b/hw/pci-bridge/pcie_root_port.c
> > > > index 09019ca05d..1d8a778709 100644
> > > > --- a/hw/pci-bridge/pcie_root_port.c
> > > > +++ b/hw/pci-bridge/pcie_root_port.c
> > > > @@ -111,7 +111,7 @@ static void rp_realize(PCIDevice *d, Error **errp)
> > > > pcie_aer_root_init(d);
> > > > rp_aer_vector_update(d);
> > > >
> > > > - if (rpc->acs_offset) {
> > > > + if (rpc->acs_offset && !s->disable_acs) {
> > >
> > > it's not like it would be used per instance,
> > > so could we use class property and with rpc->disable_acs instead of
> > > PCIESlot?
> >
> > I'm not clear I understand how class properties help;
> > object_class_property_add_bool
> > takes a getter/setter that takes an Object * parameter;
> > my reading of that is that it's the instance data so has the same
> > problem.
>
> it's possible to reach class data from setter/getter,
> for example s390_cpu_model_class_register_props().
Ah OK.
> But it will be a bit more code than here and considering
> that it's only field in parent type which is reachable through
> root port specific property only it is also ok as is as a
> fix to 4.1, so if you prefer to keep it like now
>
> Reviewed-by: Igor Mammedov <address@hidden>
Thanks!
>
>
> > Dave
> >
> > > > pcie_acs_init(d, rpc->acs_offset);
> > > > }
> > > > return;
> > > > @@ -145,6 +145,7 @@ static void rp_exit(PCIDevice *d)
> > > > static Property rp_props[] = {
> > > > DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present,
> > > > QEMU_PCIE_SLTCAP_PCP_BITNR, true),
> > > > + DEFINE_PROP_BOOL("disable-acs", PCIESlot, disable_acs, false),
> > > > DEFINE_PROP_END_OF_LIST()
> > > > };
> > > >
> > > > diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
> > > > index 09586f4641..7515430087 100644
> > > > --- a/include/hw/pci/pcie_port.h
> > > > +++ b/include/hw/pci/pcie_port.h
> > > > @@ -53,6 +53,8 @@ struct PCIESlot {
> > > > PCIExpLinkSpeed speed;
> > > > PCIExpLinkWidth width;
> > > >
> > > > + /* Disable ACS (really for a pcie_root_port) */
> > > > + bool disable_acs;
> > > > QLIST_ENTRY(PCIESlot) next;
> > > > };
> > > >
> > >
> > --
> > Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
[Qemu-devel] [PATCH 2/2] pcie_root_port: Disable ACS on older machines, Dr. David Alan Gilbert (git), 2019/07/30