hw/ppc/spapr.c | 7 ++++++- hw/ppc/spapr_pci.c | 8 ++++++++ include/hw/pci-host/spapr.h | 1 + 3 files changed, 15 insertions(+), 1 deletion(-)
In certain cases, such as PCI-passthrough with VFIO, we cannot offload
MMIO accesses to KVM unless the BAR alignment matches the host. This
patch, in conjunction with a separately submitted patch for SLOF
which allows for control of this via the device-tree, allows us to
set this alignment via QEMU.
Cc: qemu-ppc@nongnu.org
Cc: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
hw/ppc/spapr.c | 7 ++++++-
hw/ppc/spapr_pci.c | 8 ++++++++
include/hw/pci-host/spapr.h | 1 +
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 81c6c1c..321951c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3121,7 +3121,12 @@ DEFINE_SPAPR_MACHINE(2_9, "2.9", true);
* pseries-2.8
*/
#define SPAPR_COMPAT_2_8 \
- HW_COMPAT_2_8
+ HW_COMPAT_2_8 \
+ { \
+ .driver = TYPE_SPAPR_PCI_HOST_BRIDGE, \
+ .property = "mem_bar_min_align", \
+ .value = "0", \
+ }, \
static void spapr_machine_2_8_instance_options(MachineState *machine)
{
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 2a3499e..fdfd494 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1660,6 +1660,10 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
return;
}
+ if (sphb->mem_bar_min_align == (uint64_t)-1) {
+ sphb->mem_bar_min_align = qemu_real_host_page_size;
+ }
+
sphb->dtbusname = g_strdup_printf("pci@%" PRIx64, sphb->buid);
namebuf = alloca(strlen(sphb->dtbusname) + 32);
@@ -1854,6 +1858,8 @@ static Property spapr_phb_properties[] = {
DEFINE_PROP_UINT32("numa_node", sPAPRPHBState, numa_node, -1),
DEFINE_PROP_BOOL("pre-2.8-migration", sPAPRPHBState,
pre_2_8_migration, false),
+ DEFINE_PROP_UINT64("mem_bar_min_align", sPAPRPHBState, mem_bar_min_align,
+ -1),
DEFINE_PROP_END_OF_LIST(),
};
@@ -2224,6 +2230,8 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
if (ret) {
return ret;
}
+ _FDT(fdt_setprop_cell(fdt, bus_off, "qemu,mem-bar-min-align",
+ phb->mem_bar_min_align));
return 0;
}
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index dfa7614..fa33346 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -79,6 +79,7 @@ struct sPAPRPHBState {
uint64_t dma64_win_addr;
uint32_t numa_node;
+ uint64_t mem_bar_min_align;
/* Fields for migration compatibility hacks */
bool pre_2_8_migration;
--
2.7.4
On Tue, Feb 28, 2017 at 06:56:47PM -0600, Michael Roth wrote: > In certain cases, such as PCI-passthrough with VFIO, we cannot offload > MMIO accesses to KVM unless the BAR alignment matches the host. This > patch, in conjunction with a separately submitted patch for SLOF > which allows for control of this via the device-tree, allows us to > set this alignment via QEMU. > > Cc: qemu-ppc@nongnu.org > Cc: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> > Cc: David Gibson <david@gibson.dropbear.id.au> > Cc: Alexey Kardashevskiy <aik@ozlabs.ru> > Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> > --- > hw/ppc/spapr.c | 7 ++++++- > hw/ppc/spapr_pci.c | 8 ++++++++ > include/hw/pci-host/spapr.h | 1 + > 3 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 81c6c1c..321951c 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -3121,7 +3121,12 @@ DEFINE_SPAPR_MACHINE(2_9, "2.9", true); > * pseries-2.8 > */ > #define SPAPR_COMPAT_2_8 \ > - HW_COMPAT_2_8 > + HW_COMPAT_2_8 \ > + { \ > + .driver = TYPE_SPAPR_PCI_HOST_BRIDGE, \ > + .property = "mem_bar_min_align", \ > + .value = "0", \ > + }, \ > > static void spapr_machine_2_8_instance_options(MachineState *machine) > { > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c > index 2a3499e..fdfd494 100644 > --- a/hw/ppc/spapr_pci.c > +++ b/hw/ppc/spapr_pci.c > @@ -1660,6 +1660,10 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp) > return; > } > > + if (sphb->mem_bar_min_align == (uint64_t)-1) { > + sphb->mem_bar_min_align = qemu_real_host_page_size; > + } > + > sphb->dtbusname = g_strdup_printf("pci@%" PRIx64, sphb->buid); > > namebuf = alloca(strlen(sphb->dtbusname) + 32); > @@ -1854,6 +1858,8 @@ static Property spapr_phb_properties[] = { > DEFINE_PROP_UINT32("numa_node", sPAPRPHBState, numa_node, -1), > DEFINE_PROP_BOOL("pre-2.8-migration", sPAPRPHBState, > pre_2_8_migration, false), > + DEFINE_PROP_UINT64("mem_bar_min_align", sPAPRPHBState, mem_bar_min_align, > + -1), > DEFINE_PROP_END_OF_LIST(), > }; > > @@ -2224,6 +2230,8 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb, > if (ret) { > return ret; > } > + _FDT(fdt_setprop_cell(fdt, bus_off, "qemu,mem-bar-min-align", > + phb->mem_bar_min_align)); AFAICT the sensible thing to do here is to leave the property out on older machine types. In which case you need an if (phb->mem_bar_min_align) here. > > return 0; > } > diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h > index dfa7614..fa33346 100644 > --- a/include/hw/pci-host/spapr.h > +++ b/include/hw/pci-host/spapr.h > @@ -79,6 +79,7 @@ struct sPAPRPHBState { > uint64_t dma64_win_addr; > > uint32_t numa_node; > + uint64_t mem_bar_min_align; > > /* Fields for migration compatibility hacks */ > bool pre_2_8_migration; -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
Quoting David Gibson (2017-02-28 20:56:44) > On Tue, Feb 28, 2017 at 06:56:47PM -0600, Michael Roth wrote: > > In certain cases, such as PCI-passthrough with VFIO, we cannot offload > > MMIO accesses to KVM unless the BAR alignment matches the host. This > > patch, in conjunction with a separately submitted patch for SLOF > > which allows for control of this via the device-tree, allows us to > > set this alignment via QEMU. > > > > Cc: qemu-ppc@nongnu.org > > Cc: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> > > Cc: David Gibson <david@gibson.dropbear.id.au> > > Cc: Alexey Kardashevskiy <aik@ozlabs.ru> > > Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> > > --- > > hw/ppc/spapr.c | 7 ++++++- > > hw/ppc/spapr_pci.c | 8 ++++++++ > > include/hw/pci-host/spapr.h | 1 + > > 3 files changed, 15 insertions(+), 1 deletion(-) > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > index 81c6c1c..321951c 100644 > > --- a/hw/ppc/spapr.c > > +++ b/hw/ppc/spapr.c > > @@ -3121,7 +3121,12 @@ DEFINE_SPAPR_MACHINE(2_9, "2.9", true); > > * pseries-2.8 > > */ > > #define SPAPR_COMPAT_2_8 \ > > - HW_COMPAT_2_8 > > + HW_COMPAT_2_8 \ > > + { \ > > + .driver = TYPE_SPAPR_PCI_HOST_BRIDGE, \ > > + .property = "mem_bar_min_align", \ > > + .value = "0", \ > > + }, \ > > > > static void spapr_machine_2_8_instance_options(MachineState *machine) > > { > > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c > > index 2a3499e..fdfd494 100644 > > --- a/hw/ppc/spapr_pci.c > > +++ b/hw/ppc/spapr_pci.c > > @@ -1660,6 +1660,10 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp) > > return; > > } > > > > + if (sphb->mem_bar_min_align == (uint64_t)-1) { > > + sphb->mem_bar_min_align = qemu_real_host_page_size; > > + } > > + > > sphb->dtbusname = g_strdup_printf("pci@%" PRIx64, sphb->buid); > > > > namebuf = alloca(strlen(sphb->dtbusname) + 32); > > @@ -1854,6 +1858,8 @@ static Property spapr_phb_properties[] = { > > DEFINE_PROP_UINT32("numa_node", sPAPRPHBState, numa_node, -1), > > DEFINE_PROP_BOOL("pre-2.8-migration", sPAPRPHBState, > > pre_2_8_migration, false), > > + DEFINE_PROP_UINT64("mem_bar_min_align", sPAPRPHBState, mem_bar_min_align, > > + -1), > > DEFINE_PROP_END_OF_LIST(), > > }; > > > > @@ -2224,6 +2230,8 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb, > > if (ret) { > > return ret; > > } > > + _FDT(fdt_setprop_cell(fdt, bus_off, "qemu,mem-bar-min-align", > > + phb->mem_bar_min_align)); > > AFAICT the sensible thing to do here is to leave the property out on > older machine types. In which case you need an if > (phb->mem_bar_min_align) here. Yah. On the SLOF side it seemed like 64K was the safer default, which made this more of an override. But that doesn't make much sense unless you're mix-and-matching SLOFs/QEMUs. Will change it for v2. > > > > return 0; > > } > > diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h > > index dfa7614..fa33346 100644 > > --- a/include/hw/pci-host/spapr.h > > +++ b/include/hw/pci-host/spapr.h > > @@ -79,6 +79,7 @@ struct sPAPRPHBState { > > uint64_t dma64_win_addr; > > > > uint32_t numa_node; > > + uint64_t mem_bar_min_align; > > > > /* Fields for migration compatibility hacks */ > > bool pre_2_8_migration; > > -- > David Gibson | I'll have my music baroque, and my code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson
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