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Re: [Qemu-ppc] [PATCH qemu v2 4/4] spapr: Support NVIDIA V100 GPU with N
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From: |
Alexey Kardashevskiy |
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Subject: |
Re: [Qemu-ppc] [PATCH qemu v2 4/4] spapr: Support NVIDIA V100 GPU with NVLink2 |
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Date: |
Fri, 15 Feb 2019 15:42:56 +1100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 |
On 15/02/2019 14:22, David Gibson wrote:
> On Thu, Feb 14, 2019 at 04:21:44PM +1100, Alexey Kardashevskiy wrote:
>> NVIDIA V100 GPUs have on-board RAM which is mapped into the host memory
>> space and accessible as normal RAM via an NVLink bus. The VFIO-PCI driver
>> implements special regions for such GPUs and emulates an NVLink bridge.
>> NVLink2-enabled POWER9 CPUs also provide address translation services
>> which includes an ATS shootdown (ATSD) register exported via the NVLink
>> bridge device.
>>
>> This adds a quirk to VFIO to map the GPU memory and create an MR;
>> the new MR is stored in a PCI device as a QOM link. The sPAPR PCI uses
>> this to get the MR and map it to the system address space.
>> Another quirk does the same for ATSD.
>>
>> This adds 4 additional steps to the FDT builder in spapr-pci:
>>
>> 1. Search for specific GPUs and NPUs and collect findings in
>> sPAPRPHBState::nvgpus;
>>
>> 2. Add properties in the device tree such as "ibm,npu", "ibm,gpu",
>> "memory-block" and others to advertise the NVLink2 function to the guest;
>>
>> 3. Add new memory blocks with an extra "linux,memory-usable" to prevent
>> the guest OS from accessing the new memory until it is online by the GPU
>> driver in the guest;
>>
>> 4. Add a npuphb# node representing an NPU unit for every vPHB as
>> the GPU driver uses it to detect NPU2 hardware and discover links; this
>> is not backed by any QEMU device as it does need to.
>>
>> This allocates space for GPU RAM and ATSD like we do for MMIOs by
>> adding 2 new parameters to the phb_placement() hook. Older machine types
>> set these to zero.
>>
>> This puts new memory nodes in a separate NUMA node to replicate the host
>> system setup as the GPU driver relies on this.
>>
>> This adds requirement similar to EEH - one IOMMU group per vPHB.
>> The reason for this is that ATSD registers belong to a physical NPU
>> so they cannot invalidate translations on GPUs attached to another NPU.
>> It is guaranteed by the host platform as it does not mix NVLink bridges
>> or GPUs from different NPU in the same IOMMU group. If more than one
>> IOMMU group is detected on a vPHB, this disables ATSD support for that
>> vPHB and prints a warning.
>>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>> ---
>>
>> The example command line for redbud system:
>>
>> pbuild/qemu-aiku1804le-ppc64/ppc64-softmmu/qemu-system-ppc64 \
>> -nodefaults \
>> -chardev stdio,id=STDIO0,signal=off,mux=on \
>> -device spapr-vty,id=svty0,reg=0x71000110,chardev=STDIO0 \
>> -mon id=MON0,chardev=STDIO0,mode=readline -nographic -vga none \
>> -enable-kvm -m 384G \
>> -chardev socket,id=SOCKET0,server,nowait,host=localhost,port=40000 \
>> -mon chardev=SOCKET0,mode=control \
>> -smp 80,sockets=1,threads=4 \
>> -netdev "tap,id=TAP0,helper=/home/aik/qemu-bridge-helper --br=br0" \
>> -device "virtio-net-pci,id=vnet0,mac=52:54:00:12:34:56,netdev=TAP0" \
>> img/vdisk0.img \
>> -device "vfio-pci,id=vfio0004_04_00_0,host=0004:04:00.0" \
>> -device "vfio-pci,id=vfio0006_00_00_0,host=0006:00:00.0" \
>> -device "vfio-pci,id=vfio0006_00_00_1,host=0006:00:00.1" \
>> -device "vfio-pci,id=vfio0006_00_00_2,host=0006:00:00.2" \
>> -device "vfio-pci,id=vfio0004_05_00_0,host=0004:05:00.0" \
>> -device "vfio-pci,id=vfio0006_00_01_0,host=0006:00:01.0" \
>> -device "vfio-pci,id=vfio0006_00_01_1,host=0006:00:01.1" \
>> -device "vfio-pci,id=vfio0006_00_01_2,host=0006:00:01.2" \
>> -device spapr-pci-host-bridge,id=phb1,index=1 \
>> -device "vfio-pci,id=vfio0035_03_00_0,host=0035:03:00.0" \
>> -device "vfio-pci,id=vfio0007_00_00_0,host=0007:00:00.0" \
>> -device "vfio-pci,id=vfio0007_00_00_1,host=0007:00:00.1" \
>> -device "vfio-pci,id=vfio0007_00_00_2,host=0007:00:00.2" \
>> -device "vfio-pci,id=vfio0035_04_00_0,host=0035:04:00.0" \
>> -device "vfio-pci,id=vfio0007_00_01_0,host=0007:00:01.0" \
>> -device "vfio-pci,id=vfio0007_00_01_1,host=0007:00:01.1" \
>> -device "vfio-pci,id=vfio0007_00_01_2,host=0007:00:01.2" -snapshot \
>> -machine pseries \
>> -L /home/aik/t/qemu-ppc64-bios/ -d guest_errors
>>
>> Note that QEMU attaches PCI devices to the last added vPHB so first
>> 8 devices - 4:04:00.0 till 6:00:01.2 - go to the default vPHB, and
>> 35:03:00.0..7:00:01.2 to the vPHB with id=phb1.
>> ---
>> hw/vfio/pci.h | 2 +
>> include/hw/pci-host/spapr.h | 9 +
>> include/hw/ppc/spapr.h | 3 +-
>> hw/ppc/spapr.c | 25 ++-
>> hw/ppc/spapr_pci.c | 333 +++++++++++++++++++++++++++++++++++-
>> hw/vfio/pci-quirks.c | 120 +++++++++++++
>> hw/vfio/pci.c | 14 ++
>> hw/vfio/trace-events | 4 +
>> 8 files changed, 506 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
>> index b1ae4c0..706c304 100644
>> --- a/hw/vfio/pci.h
>> +++ b/hw/vfio/pci.h
>> @@ -194,6 +194,8 @@ int vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp);
>> int vfio_pci_igd_opregion_init(VFIOPCIDevice *vdev,
>> struct vfio_region_info *info,
>> Error **errp);
>> +int vfio_pci_nvidia_v100_ram_init(VFIOPCIDevice *vdev, Error **errp);
>> +int vfio_pci_nvlink2_init(VFIOPCIDevice *vdev, Error **errp);
>>
>> void vfio_display_reset(VFIOPCIDevice *vdev);
>> int vfio_display_probe(VFIOPCIDevice *vdev, Error **errp);
>> diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
>> index 51d81c4..4a665cb 100644
>> --- a/include/hw/pci-host/spapr.h
>> +++ b/include/hw/pci-host/spapr.h
>> @@ -87,6 +87,9 @@ struct sPAPRPHBState {
>> uint32_t mig_liobn;
>> hwaddr mig_mem_win_addr, mig_mem_win_size;
>> hwaddr mig_io_win_addr, mig_io_win_size;
>> + hwaddr nv2_gpa_win_addr;
>> + hwaddr nv2_atsd_win_addr;
>> + struct spapr_phb_pci_nvgpu_config *nvgpus;
>> };
>>
>> #define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
>> @@ -105,6 +108,12 @@ struct sPAPRPHBState {
>>
>> #define SPAPR_PCI_MSI_WINDOW 0x40000000000ULL
>>
>> +#define SPAPR_PCI_NV2RAM64_WIN_BASE 0x10000000000ULL /* 1 TiB */
>
> This is not a good choice - we have POWER machines with well over 1
> TiB RAM, and so it's also plausible we can get guests with over 1 TiB
> RAM which will collide with this. Especially likely with the sort of
> giant HPC guests that are most likely to have the GPUs passed through
> to them.
>
> This is why we already moved the main PCI MMIO windows up to 32 TiB
> from the lower address they used to have.
How much space do you want to leave for the guest RAM ideally? Or it is
that 32TiB and I better move GPU RAM above that?
>
>> +#define SPAPR_PCI_NV2RAM64_WIN_SIZE 0x10000000000ULL /* 1 TiB for all
>> 6xGPUs */
>> +
>> +#define SPAPR_PCI_NV2ATSD_WIN_BASE SPAPR_PCI_LIMIT
>> +#define SPAPR_PCI_NV2ATSD_WIN_SIZE (16 * 0x10000)
>> +
>> static inline qemu_irq spapr_phb_lsi_qirq(struct sPAPRPHBState *phb, int
>> pin)
>> {
>> sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index cbd276e..d9edf23 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -112,7 +112,8 @@ struct sPAPRMachineClass {
>> void (*phb_placement)(sPAPRMachineState *spapr, uint32_t index,
>> uint64_t *buid, hwaddr *pio,
>> hwaddr *mmio32, hwaddr *mmio64,
>> - unsigned n_dma, uint32_t *liobns, Error **errp);
>> + unsigned n_dma, uint32_t *liobns, hwaddr *nv2gpa,
>> + hwaddr *nv2atsd, Error **errp);
>> sPAPRResizeHPT resize_hpt_default;
>> sPAPRCapabilities default_caps;
>> sPAPRIrq *irq;
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index b967024..d18834c 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -3844,7 +3844,8 @@ static const CPUArchIdList
>> *spapr_possible_cpu_arch_ids(MachineState *machine)
>> static void spapr_phb_placement(sPAPRMachineState *spapr, uint32_t index,
>> uint64_t *buid, hwaddr *pio,
>> hwaddr *mmio32, hwaddr *mmio64,
>> - unsigned n_dma, uint32_t *liobns, Error
>> **errp)
>> + unsigned n_dma, uint32_t *liobns,
>> + hwaddr *nv2gpa, hwaddr *nv2atsd, Error
>> **errp)
>> {
>> /*
>> * New-style PHB window placement.
>> @@ -3889,6 +3890,9 @@ static void spapr_phb_placement(sPAPRMachineState
>> *spapr, uint32_t index,
>> *pio = SPAPR_PCI_BASE + index * SPAPR_PCI_IO_WIN_SIZE;
>> *mmio32 = SPAPR_PCI_BASE + (index + 1) * SPAPR_PCI_MEM32_WIN_SIZE;
>> *mmio64 = SPAPR_PCI_BASE + (index + 1) * SPAPR_PCI_MEM64_WIN_SIZE;
>> +
>> + *nv2gpa = SPAPR_PCI_NV2RAM64_WIN_BASE + index *
>> SPAPR_PCI_NV2RAM64_WIN_SIZE;
>> + *nv2atsd = SPAPR_PCI_NV2ATSD_WIN_BASE + index *
>> SPAPR_PCI_NV2ATSD_WIN_SIZE;
>> }
>>
>> static ICSState *spapr_ics_get(XICSFabric *dev, int irq)
>> @@ -4090,6 +4094,18 @@ DEFINE_SPAPR_MACHINE(4_0, "4.0", true);
>> /*
>> * pseries-3.1
>> */
>> +static void phb_placement_3_1(sPAPRMachineState *spapr, uint32_t index,
>> + uint64_t *buid, hwaddr *pio,
>> + hwaddr *mmio32, hwaddr *mmio64,
>> + unsigned n_dma, uint32_t *liobns,
>> + hwaddr *nv2gpa, hwaddr *nv2atsd, Error **errp)
>> +{
>> + spapr_phb_placement(spapr, index, buid, pio, mmio32, mmio64, n_dma,
>> liobns,
>> + nv2gpa, nv2atsd, errp);
>> + *nv2gpa = 0;
>> + *nv2atsd = 0;
>> +}
>> +
>> static void spapr_machine_3_1_class_options(MachineClass *mc)
>> {
>> sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
>> @@ -4098,6 +4114,7 @@ static void
>> spapr_machine_3_1_class_options(MachineClass *mc)
>> compat_props_add(mc->compat_props, hw_compat_3_1, hw_compat_3_1_len);
>> mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");
>> smc->update_dt_enabled = false;
>> + smc->phb_placement = phb_placement_3_1;
>> }
>>
>> DEFINE_SPAPR_MACHINE(3_1, "3.1", false);
>> @@ -4229,7 +4246,8 @@ DEFINE_SPAPR_MACHINE(2_8, "2.8", false);
>> static void phb_placement_2_7(sPAPRMachineState *spapr, uint32_t index,
>> uint64_t *buid, hwaddr *pio,
>> hwaddr *mmio32, hwaddr *mmio64,
>> - unsigned n_dma, uint32_t *liobns, Error
>> **errp)
>> + unsigned n_dma, uint32_t *liobns,
>> + hwaddr *nv2gpa, hwaddr *nv2atsd, Error **errp)
>> {
>> /* Legacy PHB placement for pseries-2.7 and earlier machine types */
>> const uint64_t base_buid = 0x800000020000000ULL;
>> @@ -4273,6 +4291,9 @@ static void phb_placement_2_7(sPAPRMachineState
>> *spapr, uint32_t index,
>> * fallback behaviour of automatically splitting a large "32-bit"
>> * window into contiguous 32-bit and 64-bit windows
>> */
>> +
>> + *nv2gpa = 0;
>> + *nv2atsd = 0;
>> }
>>
>> static void spapr_machine_2_7_class_options(MachineClass *mc)
>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>> index c3fb0ac..04a679e 100644
>> --- a/hw/ppc/spapr_pci.c
>> +++ b/hw/ppc/spapr_pci.c
>> @@ -50,6 +50,46 @@
>> #include "sysemu/hostmem.h"
>> #include "sysemu/numa.h"
>>
>> +#define PHANDLE_PCIDEV(phb, pdev) (0x12000000 | \
>> + (((phb)->index) << 16) |
>> ((pdev)->devfn))
>> +#define PHANDLE_GPURAM(phb, n) (0x110000FF | ((n) << 8) | \
>> + (((phb)->index) << 16))
>> +/* NVLink2 wants a separate NUMA node for its RAM */
>> +#define GPURAM_ASSOCIATIVITY(phb, n) (255 - ((phb)->index * 3 + (n)))
>
> IIUC this gives you non zero-based indices for the associtivity
> property. That's going to make a real mess of
> ibm,max-associativity-domains.
? It does not on the host which I mimic here. And a bunch of CUDA tests
actually rely on node numbers (which is not a huge deal but it will be
annoying for the users).
>
>> +#define PHANDLE_NVLINK(phb, gn, nn) (0x00130000 | (((phb)->index) << 8) | \
>> + ((gn) << 4) | (nn))
>> +
>> +/* Max number of these GPUs per a physical box */
>> +#define NVGPU_MAX_NUM 6
>> +
>> +/* Max number of NVLinks per GPU in any physical box */
>> +#define NVGPU_MAX_LINKS 3
>> +
>> +/*
>> + * One NVLink bridge provides one ATSD register so it should be 18.
>> + * In practice though since we allow only one group per vPHB
>
> Uh.. we do? Do you mean iommu group here? We used to enforce one per
> vPHB, but that's no longer the case. Or have you reintroduced that
> restriction?
Sort of. This is for ATSD (invalidation registers), these are advertised
to the guest via a PHB's property:
/sys/firmware/devicetree/base/address@hidden/ibm\,mmio-atsd
where /sys/firmware/devicetree/base/address@hidden is a node for
that skiboot emulated "IBM Device 04ea" bridge which represents nvlinks.
We have 2 of these bridges per a machine. ATSD registers from one NPU
cannot work on another NPU. Hence the limitation.
I mean it is still possible to put GPUs in whatever combination but if
this happens, ATSD will be disabled (i.e. not advertised). Which is not
extremely useful though.
>> which equals
>> + * to an NPU2 which has maximum 6 NVLink bridges.
>> + */
>> +#define NVGPU_MAX_ATSD 6
>> +
>> +struct spapr_phb_pci_nvgpu_config {
>> + uint64_t nv2_ram_current;
>> + uint64_t nv2_atsd_current;
>> + int num; /* number of valid entries in gpus[] */
>> + int gpunum; /* number of entries in gpus[] with gpdev!=NULL */
>> + struct {
>> + int links;
>> + uint64_t tgt;
>> + uint64_t gpa;
>> + PCIDevice *gpdev;
>> + uint64_t atsd_gpa[NVGPU_MAX_LINKS];
>> + PCIDevice *npdev[NVGPU_MAX_LINKS];
>> + uint32_t link_speed[NVGPU_MAX_LINKS];
>> + } gpus[NVGPU_MAX_NUM];
>> + uint64_t atsd_prop[NVGPU_MAX_ATSD]; /* Big Endian for DT */
>> + int atsd_num;
>> +};
>> +
>> /* Copied from the kernel arch/powerpc/platforms/pseries/msi.c */
>> #define RTAS_QUERY_FN 0
>> #define RTAS_CHANGE_FN 1
>> @@ -1255,6 +1295,7 @@ static uint32_t
>> spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
>> static void spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int
>> offset,
>> sPAPRPHBState *sphb)
>> {
>> + int i, j;
>> ResourceProps rp;
>> bool is_bridge = false;
>> int pci_status;
>> @@ -1355,6 +1396,60 @@ static void spapr_populate_pci_child_dt(PCIDevice
>> *dev, void *fdt, int offset,
>> if (sphb->pcie_ecs && pci_is_express(dev)) {
>> _FDT(fdt_setprop_cell(fdt, offset, "ibm,pci-config-space-type",
>> 0x1));
>> }
>> +
>> + if (sphb->nvgpus) {
>> + for (i = 0; i < sphb->nvgpus->num; ++i) {
>
> So, if nvgpus->num is the number of valid entries in the table..
>
>> + PCIDevice *gpdev = sphb->nvgpus->gpus[i].gpdev;
>> +
>> + if (!gpdev) {
>
> ..but you can also have gaps, couldn't you miss some if the table is sparse?
Well, nvgpus->num is the number of partially populated entries. Some
might have only GPUs, some only NPUs - whatever a creative user passed,
I just advertise it all to the guest.
Perhaps some sanity checking won't hurt but I cannot do much more here
than just making sure that we only properly advertise NPU bridges which
have a GPU attached as any other config is quite valid (like a GPU with
no nvlink or with just one nvlink).
>
>> + continue;
>> + }
>> + if (dev == gpdev) {
>> + uint32_t npus[sphb->nvgpus->gpus[i].links];
>> +
>> + for (j = 0; j < sphb->nvgpus->gpus[i].links; ++j) {
>> + PCIDevice *npdev = sphb->nvgpus->gpus[i].npdev[j];
>> +
>> + npus[j] = cpu_to_be32(PHANDLE_PCIDEV(sphb, npdev));
>> + }
>> + _FDT(fdt_setprop(fdt, offset, "ibm,npu", npus,
>> + j * sizeof(npus[0])));
>> + _FDT((fdt_setprop_cell(fdt, offset, "phandle",
>> + PHANDLE_PCIDEV(sphb, dev))));
>> + continue;
>> + }
>> + for (j = 0; j < sphb->nvgpus->gpus[i].links; ++j) {
>> + if (dev != sphb->nvgpus->gpus[i].npdev[j]) {
>> + continue;
>> + }
>> +
>> + _FDT((fdt_setprop_cell(fdt, offset, "phandle",
>> + PHANDLE_PCIDEV(sphb, dev))));
>> +
>> + _FDT(fdt_setprop_cell(fdt, offset, "ibm,gpu",
>> + PHANDLE_PCIDEV(sphb, gpdev)));
>> +
>> + _FDT((fdt_setprop_cell(fdt, offset, "ibm,nvlink",
>> + PHANDLE_NVLINK(sphb, i, j))));
>> +
>> + /*
>> + * If we ever want to emulate GPU RAM at the same location
>> as on
>> + * the host - here is the encoding GPA->TGT:
>> + *
>> + * gta = ((sphb->nv2_gpa >> 42) & 0x1) << 42;
>> + * gta |= ((sphb->nv2_gpa >> 45) & 0x3) << 43;
>> + * gta |= ((sphb->nv2_gpa >> 49) & 0x3) << 45;
>> + * gta |= sphb->nv2_gpa & ((1UL << 43) - 1);
>> + */
>> + _FDT(fdt_setprop_cell(fdt, offset, "memory-region",
>> + PHANDLE_GPURAM(sphb, i)));
>> + _FDT(fdt_setprop_u64(fdt, offset, "ibm,device-tgt-addr",
>> + sphb->nvgpus->gpus[i].tgt));
>> + _FDT(fdt_setprop_cell(fdt, offset, "ibm,nvlink-speed",
>> + sphb->nvgpus->gpus[i].link_speed[j]));
>> + }
>> + }
>> + }
>> }
>>
>> /* create OF node for pci device and required OF DT properties */
>> @@ -1596,7 +1691,9 @@ static void spapr_phb_realize(DeviceState *dev, Error
>> **errp)
>> smc->phb_placement(spapr, sphb->index,
>> &sphb->buid, &sphb->io_win_addr,
>> &sphb->mem_win_addr, &sphb->mem64_win_addr,
>> - windows_supported, sphb->dma_liobn, &local_err);
>> + windows_supported, sphb->dma_liobn,
>> + &sphb->nv2_gpa_win_addr,
>> + &sphb->nv2_atsd_win_addr, &local_err);
>> if (local_err) {
>> error_propagate(errp, local_err);
>> return;
>> @@ -1843,6 +1940,8 @@ static Property spapr_phb_properties[] = {
>> pre_2_8_migration, false),
>> DEFINE_PROP_BOOL("pcie-extended-configuration-space", sPAPRPHBState,
>> pcie_ecs, true),
>> + DEFINE_PROP_UINT64("gpa", sPAPRPHBState, nv2_gpa_win_addr, 0),
>> + DEFINE_PROP_UINT64("atsd", sPAPRPHBState, nv2_atsd_win_addr, 0),
>
> Now that index is mandatory it's probably not essential to have these
> properties, although I guess they don't hurt.
>
>> DEFINE_PROP_END_OF_LIST(),
>> };
>>
>> @@ -2069,6 +2168,80 @@ static void spapr_phb_pci_enumerate(sPAPRPHBState
>> *phb)
>>
>> }
>>
>> +static void spapr_phb_pci_find_nvgpu(PCIBus *bus, PCIDevice *pdev, void
>> *opaque)
>> +{
>> + struct spapr_phb_pci_nvgpu_config *nvgpus = opaque;
>> + PCIBus *sec_bus;
>> + Object *mr_gpu, *mr_npu;
>> + uint64_t tgt = 0, gpa, atsd = 0;
>> + int i;
>> +
>> + mr_gpu = object_property_get_link(OBJECT(pdev), "nvlink2-mr[0]", NULL);
>> + mr_npu = object_property_get_link(OBJECT(pdev), "nvlink2-atsd-mr[0]",
>> NULL);
>> + if (mr_gpu) {
>> + gpa = nvgpus->nv2_ram_current;
>> + nvgpus->nv2_ram_current +=
>> memory_region_size(MEMORY_REGION(mr_gpu));
>
> Hrm. Changing persistent state in a function called "find" makes me
> nervous.
"Gather"? "Collect"? "Scan"?
>> + } else if (mr_npu) {
>> + if (nvgpus->atsd_num == ARRAY_SIZE(nvgpus->atsd_prop)) {
>> + warn_report("Found too many ATSD registers per vPHB");
>> + } else {
>> + atsd = nvgpus->nv2_atsd_current;
>> + nvgpus->atsd_prop[nvgpus->atsd_num] = cpu_to_be64(atsd);
>> + ++nvgpus->atsd_num;
>> + nvgpus->nv2_atsd_current +=
>> + memory_region_size(MEMORY_REGION(mr_npu));
>> + }
>> + }
>> +
>> + tgt = object_property_get_uint(OBJECT(pdev), "tgt", NULL);
>
> It seems like you ought to have an object_dynamic_cast() up the top of
> here to see if is a device you care about. I guess you'd get away
> with it in practice because other devices won't have the properties
> you test for, but I'd prefer not to rely on that (especially since
> "tgt" is such a brief, generic name, which come to think of it might
> be a good idea to change anyway).
> This would probably also be clearer if you have the recursing over
> bridges in one function and the handling of a single specific device
> you're interested in delegated to a another function.
>
>> + if (tgt) {
>> + for (i = 0; i < nvgpus->num; ++i) {
>> + if (nvgpus->gpus[i].tgt == tgt) {
>> + break;
>> + }
>> + }
>> +
>> + if (i == nvgpus->num) {
>> + if (nvgpus->num == ARRAY_SIZE(nvgpus->gpus)) {
>> + warn_report("Found too many NVLink bridges per GPU");
>> + return;
>> + }
>> + ++nvgpus->num;
>> + }
>> +
>> + nvgpus->gpus[i].tgt = tgt;
>> + if (mr_gpu) {
>> + g_assert(!nvgpus->gpus[i].gpdev);
>> + nvgpus->gpus[i].gpdev = pdev;
>> + nvgpus->gpus[i].gpa = gpa;
>> + ++nvgpus->gpunum;
>> + } else {
>> + int j = nvgpus->gpus[i].links;
>> +
>> + ++nvgpus->gpus[i].links;
>> +
>> + g_assert(!nvgpus->gpus[i].npdev[j]);
>> + nvgpus->gpus[i].npdev[j] = pdev;
>> + nvgpus->gpus[i].atsd_gpa[j] = atsd;
>> + nvgpus->gpus[i].link_speed[j] =
>> + object_property_get_uint(OBJECT(pdev), "link_speed",
>> NULL);
>> + }
>> + }
>> +
>> + if ((pci_default_read_config(pdev, PCI_HEADER_TYPE, 1) !=
>> + PCI_HEADER_TYPE_BRIDGE)) {
>> + return;
>> + }
>> +
>> + sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
>> + if (!sec_bus) {
>> + return;
>> + }
>> +
>> + pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
>> + spapr_phb_pci_find_nvgpu, opaque);
>> +}
>> +
>> int spapr_populate_pci_dt(sPAPRPHBState *phb, uint32_t intc_phandle, void
>> *fdt,
>> uint32_t nr_msis)
>> {
>> @@ -2187,6 +2360,69 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
>> uint32_t intc_phandle, void *fdt,
>> spapr_phb_pci_enumerate(phb);
>> _FDT(fdt_setprop_cell(fdt, bus_off, "qemu,phb-enumerated", 0x1));
>>
>> + /* If there are existing NVLink2 MRs, unmap those before recreating */
>
> Unmapping regions shouldn't be in a function that's about populating
> the dt, it probably wants to be part of the reset path.
>
>> + if (phb->nvgpus) {
>> + for (i = 0; i < phb->nvgpus->num; ++i) {
>> + PCIDevice *gpdev = phb->nvgpus->gpus[i].gpdev;
>> + Object *nv_mrobj = object_property_get_link(OBJECT(gpdev),
>> + "nvlink2-mr[0]",
>> NULL);
>> +
>> + if (nv_mrobj) {
>> + memory_region_del_subregion(get_system_memory(),
>> + MEMORY_REGION(nv_mrobj));
>> + }
>> + for (j = 0; j < phb->nvgpus->gpus[i].links; ++j) {
>> + PCIDevice *npdev = phb->nvgpus->gpus[i].npdev[j];
>> + Object *atsd_mrobj;
>> + atsd_mrobj = object_property_get_link(OBJECT(npdev),
>> +
>> "nvlink2-atsd-mr[0]",
>> + NULL);
>> + if (atsd_mrobj) {
>> + memory_region_del_subregion(get_system_memory(),
>> + MEMORY_REGION(atsd_mrobj));
>> + }
>> + }
>> + }
>> + g_free(phb->nvgpus);
>> + phb->nvgpus = NULL;
>> + }
>> +
>> + /* Search for GPUs and NPUs */
>> + if (phb->nv2_gpa_win_addr && phb->nv2_atsd_win_addr) {
>> + phb->nvgpus = g_new0(struct spapr_phb_pci_nvgpu_config, 1);
>
> Likewise creating this internal state shouldn't be in a dt creation
> function.
>
>> + phb->nvgpus->nv2_ram_current = phb->nv2_gpa_win_addr;
>> + phb->nvgpus->nv2_atsd_current = phb->nv2_atsd_win_addr;
>> +
>> + pci_for_each_device(bus, pci_bus_num(bus),
>> + spapr_phb_pci_find_nvgpu, phb->nvgpus);
>> +
>> + if (!phb->nvgpus->gpunum) {
>> + /* We did not find any interesting GPU */
>> + g_free(phb->nvgpus);
>> + phb->nvgpus = NULL;
>> + } else {
>> + /*
>> + * ibm,mmio-atsd contains ATSD registers; these belong to an
>> NPU PHB
>> + * which we do not emulate as a separate device. Instead we put
>> + * ibm,mmio-atsd to the vPHB with GPU and make sure that we do
>> not
>> + * put GPUs from different IOMMU groups to the same vPHB to
>> ensure
>> + * that the guest will use ATSDs from the corresponding NPU.
>> + */
>> + if (!spapr_phb_eeh_available(phb)) {
>
> That's making assumptions about what spapr_phb_eeh_available() tests
> which might not always be warranted.
Correct. I could globally rename these helpers to "is_single_iommugroup"
to test if there is just a single IOMMU group per vPHB unless there is a
better idea may be?
>
>> + warn_report("ATSD requires a separate vPHB per GPU IOMMU
>> group");
>> + } else if (!phb->nvgpus->atsd_num) {
>> + warn_report("No ATSD registers found");
>> + } else if (phb->nvgpus->atsd_num > 8) {
>> + warn_report("Bogus ATSD configuration is found");
>> + } else {
>> + _FDT((fdt_setprop(fdt, bus_off, "ibm,mmio-atsd",
>> + phb->nvgpus->atsd_prop,
>> + phb->nvgpus->atsd_num *
>> + sizeof(phb->nvgpus->atsd_prop[0]))));
>> + }
>> + }
>> + }
>> +
>> /* Populate tree nodes with PCI devices attached */
>> s_fdt.fdt = fdt;
>> s_fdt.node_off = bus_off;
>> @@ -2201,6 +2437,101 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
>> uint32_t intc_phandle, void *fdt,
>> return ret;
>> }
>>
>> + if (phb->nvgpus) {
>> + /* Add memory nodes for GPU RAM and mark them unusable */
>> + for (i = 0; i < phb->nvgpus->num; ++i) {
>> + PCIDevice *gpdev = phb->nvgpus->gpus[i].gpdev;
>> + Object *nv_mrobj = object_property_get_link(OBJECT(gpdev),
>> + "nvlink2-mr[0]",
>> NULL);
>> + char *mem_name;
>> + int off;
>> + uint32_t at = cpu_to_be32(GPURAM_ASSOCIATIVITY(phb, i));
>> + uint32_t associativity[] = { cpu_to_be32(0x4), at, at, at, at };
>
> Putting at at every level of the associativity property seems bogus.
>
> I mean it's kind of bogus we have 4 or 5 levels of associativity
> anyway (I think that was just copied from a PowerVM setup). At
> present level 4 is the qemu node, and the ones above it are always 0.
>
> Possibly it would make sense for one of the higher levels to indicate
> system vs. NVLink RAM (0 or 1), then a single value for which NVLink
> node at level 4.
The only reason I did this in this way was the existing powernv config.
Perhaps the nvidia driver can cope with what you proposed, I'll give it
a try.
>
>> + uint64_t nv2_size = object_property_get_uint(nv_mrobj,
>> + "size", NULL);
>> + uint64_t mem_reg_property[2] = {
>
> If there's a newline here..
>
>> + cpu_to_be64(phb->nvgpus->gpus[i].gpa),
>> cpu_to_be64(nv2_size) };
>
> ..there should be one here
> ...................................................^
>
>> +
>> + mem_name = g_strdup_printf("address@hidden",
>> phb->nvgpus->gpus[i].gpa);
>> + off = fdt_add_subnode(fdt, 0, mem_name);
>> + _FDT(off);
>> + _FDT((fdt_setprop_string(fdt, off, "device_type", "memory")));
>> + _FDT((fdt_setprop(fdt, off, "reg", mem_reg_property,
>> + sizeof(mem_reg_property))));
>> + _FDT((fdt_setprop(fdt, off, "ibm,associativity", associativity,
>> + sizeof(associativity))));
>> +
>> + _FDT((fdt_setprop_string(fdt, off, "compatible",
>> + "ibm,coherent-device-memory")));
>> + mem_reg_property[1] = 0;
>> + _FDT((fdt_setprop(fdt, off, "linux,usable-memory",
>> mem_reg_property,
>> + sizeof(mem_reg_property))));
>> + _FDT((fdt_setprop_cell(fdt, off, "phandle",
>> + PHANDLE_GPURAM(phb, i))));
>> +
>> + g_free(mem_name);
>> + }
>> +
>> + /* Add NPUs with links underneath */
>> + if (phb->nvgpus->num) {
>> + char *npuname = g_strdup_printf("npuphb%d", phb->index);
>> + int npuoff = fdt_add_subnode(fdt, 0, npuname);
>> + int linkidx = 0;
>> +
>> + _FDT(npuoff);
>> + _FDT(fdt_setprop_cell(fdt, npuoff, "#address-cells", 1));
>> + _FDT(fdt_setprop_cell(fdt, npuoff, "#size-cells", 0));
>> + /* Advertise NPU as POWER9 so the guest can enable NPU2
>> contexts */
>> + _FDT((fdt_setprop_string(fdt, npuoff, "compatible",
>> + "ibm,power9-npu")));
>> + g_free(npuname);
>> +
>> + for (i = 0; i < phb->nvgpus->num; ++i) {
>> + for (j = 0; j < phb->nvgpus->gpus[i].links; ++j) {
>
> Here you assume that every entry up to nvgpus->num is populated, which
> you didn't elsewhere in the code.
Populated or half populated. Here I expose one NVLink per one passed
through IBM bridge, this ignores whether or not there is a GPU. There
should be a GPU and if there is none, then skiboot won't create the
bridges so I can have additional tests here but they won't fail and not
having them won't break things apart.
>
>> + char *linkname = g_strdup_printf("address@hidden",
>> linkidx);
>> + int off = fdt_add_subnode(fdt, npuoff, linkname);
>> +
>> + _FDT(off);
>> + _FDT((fdt_setprop_cell(fdt, off, "reg", linkidx)));
>
> Generally it's better to base 'reg' off some absolute property rather
> than arbitrary index. Could you derive linkidx from i & j instead?
I can probably just ditch this one.
>
>> + _FDT((fdt_setprop_string(fdt, off, "compatible",
>> + "ibm,npu-link")));
>> + _FDT((fdt_setprop_cell(fdt, off, "phandle",
>> + PHANDLE_NVLINK(phb, i, j))));
>> + _FDT((fdt_setprop_cell(fdt, off, "ibm,npu-link-index",
>> + linkidx)));
>> + g_free(linkname);
>> + ++linkidx;
>> + }
>> + }
>> + }
>> +
>> + /* Finally, when we finished with the device tree, map subregions */
>
> Shouldn't be in a device tree function.
>
>> + for (i = 0; i < phb->nvgpus->num; ++i) {
>> + PCIDevice *gpdev = phb->nvgpus->gpus[i].gpdev;
>> + Object *nv_mrobj = object_property_get_link(OBJECT(gpdev),
>> + "nvlink2-mr[0]",
>> NULL);
>> +
>> + if (nv_mrobj) {
>> + memory_region_add_subregion(get_system_memory(),
>> + phb->nvgpus->gpus[i].gpa,
>> + MEMORY_REGION(nv_mrobj));
>> + }
>> + for (j = 0; j < phb->nvgpus->gpus[i].links; ++j) {
>> + PCIDevice *npdev = phb->nvgpus->gpus[i].npdev[j];
>> + Object *atsd_mrobj;
>> + atsd_mrobj = object_property_get_link(OBJECT(npdev),
>> + "nvlink2-atsd-mr[0]",
>> + NULL);
>> + if (atsd_mrobj) {
>> + hwaddr atsd_gpa = phb->nvgpus->gpus[i].atsd_gpa[j];
>> +
>> + memory_region_add_subregion(get_system_memory(),
>> atsd_gpa,
>> + MEMORY_REGION(atsd_mrobj));
>> + }
>> + }
>> + }
>> + } /* if (phb->nvgpus) */
>> +
>> return 0;
>> }
>>
>> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
>> index 40a1200..faeb9c5 100644
>> --- a/hw/vfio/pci-quirks.c
>> +++ b/hw/vfio/pci-quirks.c
>> @@ -2180,3 +2180,123 @@ int vfio_add_virt_caps(VFIOPCIDevice *vdev, Error
>> **errp)
>>
>> return 0;
>> }
>> +
>> +static void vfio_pci_nvlink2_get_tgt(Object *obj, Visitor *v,
>> + const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + uint64_t tgt = (uint64_t) opaque;
>> + visit_type_uint64(v, name, &tgt, errp);
>> +}
>> +
>> +static void vfio_pci_nvlink2_get_link_speed(Object *obj, Visitor *v,
>> + const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + uint32_t link_speed = (uint32_t)(uint64_t) opaque;
>> + visit_type_uint32(v, name, &link_speed, errp);
>> +}
>> +
>> +int vfio_pci_nvidia_v100_ram_init(VFIOPCIDevice *vdev, Error **errp)
>> +{
>> + int ret;
>> + void *p;
>> + struct vfio_region_info *nv2region = NULL;
>> + struct vfio_info_cap_header *hdr;
>> + MemoryRegion *nv2mr = g_malloc0(sizeof(*nv2mr));
>> +
>> + ret = vfio_get_dev_region_info(&vdev->vbasedev,
>> + VFIO_REGION_TYPE_PCI_VENDOR_TYPE |
>> + PCI_VENDOR_ID_NVIDIA,
>> + VFIO_REGION_SUBTYPE_NVIDIA_NVLINK2_RAM,
>> + &nv2region);
>> + if (ret) {
>> + return ret;
>> + }
>> +
>> + p = mmap(NULL, nv2region->size, PROT_READ | PROT_WRITE | PROT_EXEC,
>> + MAP_SHARED, vdev->vbasedev.fd, nv2region->offset);
>> +
>> + if (!p) {
>> + return -errno;
>> + }
>> +
>> + memory_region_init_ram_ptr(nv2mr, OBJECT(vdev), "nvlink2-mr",
>> + nv2region->size, p);
>> +
>> + hdr = vfio_get_region_info_cap(nv2region,
>> + VFIO_REGION_INFO_CAP_NVLINK2_SSATGT);
>> + if (hdr) {
>> + struct vfio_region_info_cap_nvlink2_ssatgt *cap = (void *) hdr;
>> +
>> + object_property_add(OBJECT(vdev), "tgt", "uint64",
>> + vfio_pci_nvlink2_get_tgt, NULL, NULL,
>> + (void *) cap->tgt, NULL);
>> + trace_vfio_pci_nvidia_gpu_setup_quirk(vdev->vbasedev.name, cap->tgt,
>> + nv2region->size);
>> + }
>> + g_free(nv2region);
>> +
>> + return 0;
>> +}
>> +
>> +int vfio_pci_nvlink2_init(VFIOPCIDevice *vdev, Error **errp)
>> +{
>> + int ret;
>> + void *p;
>> + struct vfio_region_info *atsd_region = NULL;
>> + struct vfio_info_cap_header *hdr;
>> +
>> + ret = vfio_get_dev_region_info(&vdev->vbasedev,
>> + VFIO_REGION_TYPE_PCI_VENDOR_TYPE |
>> + PCI_VENDOR_ID_IBM,
>> + VFIO_REGION_SUBTYPE_IBM_NVLINK2_ATSD,
>> + &atsd_region);
>> + if (ret) {
>> + return ret;
>> + }
>> +
>> + /* Some NVLink bridges come without assigned ATSD, skip MR part */
>> + if (atsd_region->size) {
>> + MemoryRegion *atsd_mr = g_malloc0(sizeof(*atsd_mr));
>> +
>> + p = mmap(NULL, atsd_region->size, PROT_READ | PROT_WRITE |
>> PROT_EXEC,
>
> PROT_EXEC ?
Yes, why? We can execute from that memory (nothing does now or probably
ever will but still can).
>
>> + MAP_SHARED, vdev->vbasedev.fd, atsd_region->offset);
>> +
>> + if (!p) {
>> + return -errno;
>> + }
>> +
>> + memory_region_init_ram_device_ptr(atsd_mr, OBJECT(vdev),
>> + "nvlink2-atsd-mr",
>> + atsd_region->size,
>> + p);
>> + }
>> +
>> + hdr = vfio_get_region_info_cap(atsd_region,
>> + VFIO_REGION_INFO_CAP_NVLINK2_SSATGT);
>> + if (hdr) {
>> + struct vfio_region_info_cap_nvlink2_ssatgt *cap = (void *) hdr;
>> +
>> + object_property_add(OBJECT(vdev), "tgt", "uint64",
>> + vfio_pci_nvlink2_get_tgt, NULL, NULL,
>> + (void *) cap->tgt, NULL);
>> + trace_vfio_pci_nvlink2_setup_quirk_ssatgt(vdev->vbasedev.name,
>> cap->tgt,
>> + atsd_region->size);
>> + }
>> +
>> + hdr = vfio_get_region_info_cap(atsd_region,
>> + VFIO_REGION_INFO_CAP_NVLINK2_LNKSPD);
>> + if (hdr) {
>> + struct vfio_region_info_cap_nvlink2_lnkspd *cap = (void *) hdr;
>> +
>> + object_property_add(OBJECT(vdev), "link_speed", "uint32",
>> + vfio_pci_nvlink2_get_link_speed, NULL, NULL,
>> + (void *) (uint64_t) cap->link_speed, NULL);
>> + trace_vfio_pci_nvlink2_setup_quirk_lnkspd(vdev->vbasedev.name,
>> + cap->link_speed);
>> + }
>> + g_free(atsd_region);
>> +
>> + return 0;
>> +}
>> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>> index dd12f36..07aa141 100644
>> --- a/hw/vfio/pci.c
>> +++ b/hw/vfio/pci.c
>> @@ -3069,6 +3069,20 @@ static void vfio_realize(PCIDevice *pdev, Error
>> **errp)
>> goto out_teardown;
>> }
>>
>> + if (vdev->vendor_id == PCI_VENDOR_ID_NVIDIA) {
>
> Surely we should be checking device id as well as vendor. nVidia
> makes a lot of cards and most of them don't do nvlink2.
If they do not - the host driver will return an error, end of story. Why
is this approach exactly bad?
>
>> + ret = vfio_pci_nvidia_v100_ram_init(vdev, errp);
>> + if (ret && ret != -ENODEV) {
>> + error_report("Failed to setup NVIDIA V100 GPU RAM");
>> + }
>> + }
>> +
>> + if (vdev->vendor_id == PCI_VENDOR_ID_IBM) {
>
> And IBM makes even more.
Same here - the driver just errors out.
I'll fix the rest of the comments. Thanks,
>
>> + ret = vfio_pci_nvlink2_init(vdev, errp);
>> + if (ret && ret != -ENODEV) {
>> + error_report("Failed to setup NVlink2 bridge");
>> + }
>> + }
>> +
>> vfio_register_err_notifier(vdev);
>> vfio_register_req_notifier(vdev);
>> vfio_setup_resetfn_quirk(vdev);
>> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
>> index 579be19..6866884 100644
>> --- a/hw/vfio/trace-events
>> +++ b/hw/vfio/trace-events
>> @@ -87,6 +87,10 @@ vfio_pci_igd_opregion_enabled(const char *name) "%s"
>> vfio_pci_igd_host_bridge_enabled(const char *name) "%s"
>> vfio_pci_igd_lpc_bridge_enabled(const char *name) "%s"
>>
>> +vfio_pci_nvidia_gpu_setup_quirk(const char *name, uint64_t tgt, uint64_t
>> size) "%s tgt=0x%"PRIx64" size=0x%"PRIx64
>> +vfio_pci_nvlink2_setup_quirk_ssatgt(const char *name, uint64_t tgt,
>> uint64_t size) "%s tgt=0x%"PRIx64" size=0x%"PRIx64
>> +vfio_pci_nvlink2_setup_quirk_lnkspd(const char *name, uint32_t link_speed)
>> "%s link_speed=0x%x"
>> +
>> # hw/vfio/common.c
>> vfio_region_write(const char *name, int index, uint64_t addr, uint64_t
>> data, unsigned size) " (%s:region%d+0x%"PRIx64", 0x%"PRIx64 ", %d)"
>> vfio_region_read(char *name, int index, uint64_t addr, unsigned size,
>> uint64_t data) " (%s:region%d+0x%"PRIx64", %d) = 0x%"PRIx64
>
--
Alexey
[Qemu-ppc] [PATCH qemu v2 2/4] vfio/spapr: Rename local systempagesize variable, Alexey Kardashevskiy, 2019/02/14
Re: [Qemu-ppc] [PATCH qemu v2 0/4] spapr_pci, vfio: NVIDIA V100 + POWER9 passthrough, Alex Williamson, 2019/02/14