On Wed, Jun 08, 2016 at 04:09:57PM +1000, Alexey Kardashevskiy wrote:
> On 08/06/16 15:57, David Gibson wrote:
> > On Mon, Jun 06, 2016 at 06:12:58PM +1000, Alexey Kardashevskiy wrote:
> >> On 06/06/16 15:57, David Gibson wrote:
> >>> On Wed, Jun 01, 2016 at 06:57:42PM +1000, Alexey Kardashevskiy wrote:
> >>>> This adds support for Dynamic DMA Windows (DDW) option defined by
> >>>> the SPAPR specification which allows to have additional DMA window(s)
> >>>>
> >>>> The "ddw" property is enabled by default on a PHB but for compatibility
> >>>> the pseries-2.5 machine (TODO: update version) and older disable it.
> >>>
> >>> Looks like your todo is now todone, but you need to update the commit
> >>> message.
> >>>
> >>>> This also creates a single DMA window for the older machines to
> >>>> maintain backward migration.
> >>>>
> >>>> This implements DDW for PHB with emulated and VFIO devices. The host
> >>>> kernel support is required. The advertised IOMMU page sizes are 4K and
> >>>> 64K; 16M pages are supported but not advertised by default, in order to
> >>>> enable them, the user has to specify "pgsz" property for PHB and
> >>>> enable huge pages for RAM.
> >>>>
> >>>> The existing linux guests try creating one additional huge DMA window
> >>>> with 64K or 16MB pages and map the entire guest RAM to. If succeeded,
> >>>> the guest switches to dma_direct_ops and never calls TCE hypercalls
> >>>> (H_PUT_TCE,...) again. This enables VFIO devices to use the entire RAM
> >>>> and not waste time on map/unmap later. This adds a "dma64_win_addr"
> >>>> property which is a bus address for the 64bit window and by default
> >>>> set to 0x800.0000.0000.0000 as this is what the modern POWER8 hardware
> >>>> uses and this allows having emulated and VFIO devices on the same bus.
> >>>>
> >>>> This adds 4 RTAS handlers:
> >>>> * ibm,query-pe-dma-window
> >>>> * ibm,create-pe-dma-window
> >>>> * ibm,remove-pe-dma-window
> >>>> * ibm,reset-pe-dma-window
> >>>> These are registered from type_init() callback.
> >>>>
> >>>> These RTAS handlers are implemented in a separate file to avoid polluting
> >>>> spapr_iommu.c with PCI.
> >>>>
> >>>> This changes sPAPRPHBState::dma_liobn to an array to allow 2 LIOBNs.
> >>>>
> >>>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> >>>
> >>> Looks pretty close to ready.
> >>>
> >>> There are a handful of nits and one real error noted below.
> >>>
> >>>> ---
> >>>> Changes:
> >>>> v17:
> >>>> * fixed: "query" did return non-page-shifted value when memory hotplug
> >>>> is enabled
> >>>>
> >>>> v16:
> >>>> * s/dma_liobn/dma_liobn[SPAPR_PCI_DMA_MAX_WINDOWS]/
> >>>> * s/SPAPR_PCI_LIOBN()/dma_liobn[]/
> >>>>
> >>>> v15:
> >>>> * moved page mask filtering to PHB realize(), use "-mempath" to know
> >>>> if there are huge pages
> >>>> * fixed error reporting in RTAS handlers
> >>>> * max window size accounts now hotpluggable memory boundaries
> >>>> ---
> >>>> hw/ppc/Makefile.objs | 1 +
> >>>> hw/ppc/spapr.c | 5 +
> >>>> hw/ppc/spapr_pci.c | 77 +++++++++---
> >>>> hw/ppc/spapr_rtas_ddw.c | 293
> >>>> ++++++++++++++++++++++++++++++++++++++++++++
> >>>> include/hw/pci-host/spapr.h | 8 +-
> >>>> include/hw/ppc/spapr.h | 16 ++-
> >>>> trace-events | 4 +
> >>>> 7 files changed, 383 insertions(+), 21 deletions(-)
> >>>> create mode 100644 hw/ppc/spapr_rtas_ddw.c
> >>>>
> >>>> diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
> >>>> index c1ffc77..986b36f 100644
> >>>> --- a/hw/ppc/Makefile.objs
> >>>> +++ b/hw/ppc/Makefile.objs
> >>>> @@ -7,6 +7,7 @@ obj-$(CONFIG_PSERIES) += spapr_pci.o spapr_rtc.o
> >>>> spapr_drc.o spapr_rng.o
> >>>> ifeq ($(CONFIG_PCI)$(CONFIG_PSERIES)$(CONFIG_LINUX), yyy)
> >>>> obj-y += spapr_pci_vfio.o
> >>>> endif
> >>>> +obj-$(CONFIG_PSERIES) += spapr_rtas_ddw.o
> >>>> # PowerPC 4xx boards
> >>>> obj-y += ppc405_boards.o ppc4xx_devs.o ppc405_uc.o ppc440_bamboo.o
> >>>> obj-y += ppc4xx_pci.o
> >>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> >>>> index 44e401a..6ddcda9 100644
> >>>> --- a/hw/ppc/spapr.c
> >>>> +++ b/hw/ppc/spapr.c
> >>>> @@ -2366,6 +2366,11 @@ DEFINE_SPAPR_MACHINE(2_6, "2.6", true);
> >>>> .driver = "spapr-vlan", \
> >>>> .property = "use-rx-buffer-pools", \
> >>>> .value = "off", \
> >>>> + }, \
> >>>> + {\
> >>>> + .driver = TYPE_SPAPR_PCI_HOST_BRIDGE,\
> >>>> + .property = "ddw",\
> >>>> + .value = stringify(off),\
> >>>> },
> >>>>
> >>>> static void spapr_machine_2_5_instance_options(MachineState *machine)
> >>>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> >>>> index 68de523..bcf0360 100644
> >>>> --- a/hw/ppc/spapr_pci.c
> >>>> +++ b/hw/ppc/spapr_pci.c
> >>>> @@ -35,6 +35,7 @@
> >>>> #include "hw/ppc/spapr.h"
> >>>> #include "hw/pci-host/spapr.h"
> >>>> #include "exec/address-spaces.h"
> >>>> +#include "exec/ram_addr.h"
> >>>> #include <libfdt.h>
> >>>> #include "trace.h"
> >>>> #include "qemu/error-report.h"
> >>>> @@ -45,6 +46,7 @@
> >>>> #include "hw/ppc/spapr_drc.h"
> >>>> #include "sysemu/device_tree.h"
> >>>> #include "sysemu/kvm.h"
> >>>> +#include "sysemu/hostmem.h"
> >>>>
> >>>> #include "hw/vfio/vfio.h"
> >>>>
> >>>> @@ -1088,7 +1090,7 @@ static void
> >>>> spapr_phb_add_pci_device(sPAPRDRConnector *drc,
> >>>> int fdt_start_offset = 0, fdt_size;
> >>>>
> >>>> if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
> >>>> - sPAPRTCETable *tcet = spapr_tce_find_by_liobn(phb->dma_liobn);
> >>>> + sPAPRTCETable *tcet =
> >>>> spapr_tce_find_by_liobn(phb->dma_liobn[0]);
> >>>>
> >>>> spapr_tce_set_need_vfio(tcet, true);
> >>>> }
> >>>
> >>> Hang on.. I thought you'd got rid of the need for this explicit
> >>> set_need_vfio() stuff.
> >>
> >>
> >> It is in 12/12 (which I'll split in 2 halves when I respin this), I moved
> >> it to the end as it is not essential for DDW itself.
> >
> > Yes, sorry, I saw that shortly after writing this.
> >
> >>>> @@ -1310,11 +1312,14 @@ static void spapr_phb_realize(DeviceState *dev,
> >>>> Error **errp)
> >>>> PCIBus *bus;
> >>>> uint64_t msi_window_size = 4096;
> >>>> sPAPRTCETable *tcet;
> >>>> + const unsigned windows_supported =
> >>>> + sphb->ddw_enabled ? SPAPR_PCI_DMA_MAX_WINDOWS : 1;
> >>>>
> >>>> if (sphb->index != (uint32_t)-1) {
> >>>> hwaddr windows_base;
> >>>>
> >>>> - if ((sphb->buid != (uint64_t)-1) || (sphb->dma_liobn !=
> >>>> (uint32_t)-1)
> >>>> + if ((sphb->buid != (uint64_t)-1) || (sphb->dma_liobn[0] !=
> >>>> (uint32_t)-1)
> >>>> + || ((sphb->dma_liobn[1] != (uint32_t)-1) &&
> >>>> (windows_supported > 1))
> >>>> || (sphb->mem_win_addr != (hwaddr)-1)
> >>>> || (sphb->io_win_addr != (hwaddr)-1)) {
> >>>> error_setg(errp, "Either \"index\" or other parameters must"
> >>>> @@ -1329,7 +1334,9 @@ static void spapr_phb_realize(DeviceState *dev,
> >>>> Error **errp)
> >>>> }
> >>>>
> >>>> sphb->buid = SPAPR_PCI_BASE_BUID + sphb->index;
> >>>> - sphb->dma_liobn = SPAPR_PCI_LIOBN(sphb->index, 0);
> >>>> + for (i = 0; i < windows_supported; ++i) {
> >>>> + sphb->dma_liobn[i] = SPAPR_PCI_LIOBN(sphb->index, i);
> >>>> + }
> >>>>
> >>>> windows_base = SPAPR_PCI_WINDOW_BASE
> >>>> + sphb->index * SPAPR_PCI_WINDOW_SPACING;
> >>>> @@ -1342,8 +1349,9 @@ static void spapr_phb_realize(DeviceState *dev,
> >>>> Error **errp)
> >>>> return;
> >>>> }
> >>>>
> >>>> - if (sphb->dma_liobn == (uint32_t)-1) {
> >>>> - error_setg(errp, "LIOBN not specified for PHB");
> >>>> + if ((sphb->dma_liobn[0] == (uint32_t)-1) ||
> >>>> + ((sphb->dma_liobn[1] == (uint32_t)-1) && (windows_supported >
> >>>> 1))) {
> >>>> + error_setg(errp, "LIOBN(s) not specified for PHB");
> >>>> return;
> >>>> }
> >>>
> >>> Hrm.. there's a bit of false generality here, since this would break
> >>> if windows_supported > 2, and dma_liobn[2] was not specified. Not
> >>> urgent for the initial commit though.
> >>
> >>
> >> Is s/windows_supported > 1/windows_supported == 2/ any better here?
> >
> > Not really. Unless you also have a windows_supported > 2 case (which
> > could just error / abort / whatever).
>
>
> It cannot be >2 as SPAPR_PCI_DMA_MAX_WINDOWS is defined as "2" now and it
> is quite unlikely to change in the future.
Yes, I know, but the value of MAX_WINDOWS isn't obvious if you're just
looking at this code. My point is that a casual look at this code
suggests it will handle arbitrary windows_supported values, but that's
not actually the case. This is generally bad practice.
> What do I do right now? :)
Well, as I said it's not urgent for the first commit. Just leave it
as it is and we'll deal with the consequences later.
--
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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