Re: [Qemu-ppc] [PATCH v5 4/4] spapr_pci: populate ibm,loc-code

[Nikunj A Dadhania]

Alexey Kardashevskiy <address@hidden> writes:

> On 05/19/2015 06:26 PM, Nikunj A Dadhania wrote:
>> Each hardware instance has a platform unique location code.  The OF
>> device tree that describes a part of a hardware entity must include
>> the “ibm,loc-code” property with a value that represents the location
>> code for that hardware entity.
>>
>> Populate ibm,loc-code.
>>
>> 1) PCI passthru devices need to identify with its own ibm,loc-code
>>     available on the host. In failure cases use:
>>     vfio_<name>:<phb-index>:<slot>.<fn>
>>
>> 2) Emulated devices encode as following:
>>     qemu_<name>:<phb-index>:<slot>.<fn>
>>
>> Signed-off-by: Nikunj A Dadhania <address@hidden>
>> ---
>>   hw/ppc/spapr_pci.c | 81 
>> ++++++++++++++++++++++++++++++++++++++++++++++--------
>>   1 file changed, 69 insertions(+), 12 deletions(-)
>>
>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>> index 12f1b9c..dd77119 100644
>> --- a/hw/ppc/spapr_pci.c
>> +++ b/hw/ppc/spapr_pci.c
>> @@ -769,6 +769,61 @@ static uint32_t 
>> spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
>>       return drck->get_index(drc);
>>   }
>>
>> +static char *spapr_phb_vfio_get_loc_code(sPAPRPHBState *sphb,  PCIDevice 
>> *pdev)
>> +{
>> +    char *path = NULL, *buf = NULL;
>> +    char *host = NULL;
>
> Why not put them all in one line (or split into 3 lines :) )?

Sure.

>
>
>> +
>> +    /* Get the PCI VFIO host id */
>> +    host = object_property_get_str(OBJECT(pdev), "host", NULL);
>> +    if (!host) {
>> +        goto err_out;
>> +    }
>> +
>> +    /* Construct the path of the file that will give us the DT location */
>> +    path = g_strdup_printf("/sys/bus/pci/devices/%s/devspec", host);
>> +    g_free(host);
>> +    if (path && !g_file_get_contents(path, &buf, NULL, NULL)) {
>> +        goto err_out;
>> +    }
>> +    g_free(path);
>> +
>> +    /* Construct and read from host device tree the loc-code */
>> +    path = g_strdup_printf("/proc/device-tree%s/ibm,loc-code", buf);
>> +    g_free(buf);
>> +    if (path && !g_file_get_contents(path, &buf, NULL, NULL)) {
>
> If path==NULL, you'll return bad buf.

Oh, got it wrong.

>
>
>> +        goto err_out;
>> +    }
>> +    return buf;
>> +
>> +err_out:
>> +    g_free(path);
>> +    return NULL;
>> +}
>> +
>> +static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
>> +{
>> +    char *buf;
>> +    char devtype[16] = "qemu";
>
> I still like "const char *s = "qemu";" better.

Yes, was waiting for respin after review.

>
>
>> +
>> +    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
>> +        buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
>> +        if (buf) {
>> +            return buf;
>> +        }
>> +        snprintf(devtype, 4, "vfio");
>
> With "const", you could just do devtype = "vfio".
>
> Also,
> =====
> char devtype[16] = { 0xaa,  0xaa, 0xaa, 0xaa, 0xaa };
> snprintf(devtype, 4, "vfio");
> printf("%x %x %x\n", devtype[2], devtype[3], devtype[4]);
> ====
>
> produces on my laptop (gcc 4.9.2) this:
>
> address@hidden ~]$ ./a.out
> 69 0 ffffffaa
>
>
> Is it different where you tested this?
>
>
>> +    }
>> +    /*
>> +     * For emulated devices and VFIO-failure case, make up
>> +     * the loc-code.
>> +     */
>> +    buf = g_strdup_printf("%s_%s:%02d:%02d.%1d",
>
> How is "1d" different here from just "d"? If @devfn>10, all digits will be 
> printed.

A device can have only 8 functions, right ?

>
>
>> +                          devtype, pdev->name,
>> +                          sphb->index, PCI_SLOT(pdev->devfn),
>> +                          PCI_FUNC(pdev->devfn));
>> +    return buf;
>> +}
>> +
>>   /* Macros to operate with address in OF binding to PCI */
>>   #define b_x(x, p, l)    (((x) & ((1<<(l))-1)) << (p))
>>   #define b_n(x)          b_x((x), 31, 1) /* 0 if relocatable */
>> @@ -906,12 +961,12 @@ static void populate_resource_props(PCIDevice *d, 
>> ResourceProps *rp)
>>   }
>>
>>   static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int 
>> offset,
>> -                                       sPAPRPHBState *sphb,
>> -                                       const char *drc_name)
>> +                                       sPAPRPHBState *sphb)
>>   {
>>       ResourceProps rp;
>>       bool is_bridge = false;
>>       int pci_status;
>> +    char *buf = NULL;
>>       uint32_t drc_index = spapr_phb_get_pci_drc_index(sphb, dev);
>>
>>       if (pci_default_read_config(dev, PCI_HEADER_TYPE, 1) ==
>> @@ -973,9 +1028,13 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, 
>> void *fdt, int offset,
>>        * processed by OF beforehand
>>        */
>>       _FDT(fdt_setprop_string(fdt, offset, "name", "pci"));
>> -    if (drc_name) {
>> -        _FDT(fdt_setprop(fdt, offset, "ibm,loc-code", drc_name,
>> -                         strlen(drc_name)));
>> +    buf = spapr_phb_get_loc_code(sphb, dev);
>> +    if (!buf) {
>> +        error_report("Failed setting the ibm,loc-code");
>> +        return -1;
>> +    } else {
>
> No need in "else".

Yeah.

>
>> +        _FDT(fdt_setprop_string(fdt, offset, "ibm,loc-code", buf));
>> +        g_free(buf);
>>       }
>>       if (drc_index) {
>>           _FDT(fdt_setprop_cell(fdt, offset, "ibm,my-drc-index", drc_index));
>> @@ -1003,8 +1062,7 @@ typedef struct sPAPRFDT {
>>   } sPAPRFDT;
>>
>>   /* create OF node for pci device and required OF DT properties */
>> -static int spapr_create_pci_child_dt(PCIDevice *pdev, sPAPRFDT *p,
>> -                                     const char *drc_name)
>> +static int spapr_create_pci_child_dt(PCIDevice *pdev, sPAPRFDT *p)
>>   {
>>       int offset, ret;
>>       char nodename[64];
>> @@ -1017,8 +1075,8 @@ static int spapr_create_pci_child_dt(PCIDevice *pdev, 
>> sPAPRFDT *p,
>>           sprintf(nodename, "address@hidden", slot);
>>       }
>>       offset = fdt_add_subnode(p->fdt, p->node_off, nodename);
>> -    ret = spapr_populate_pci_child_dt(pdev, p->fdt, offset, p->sphb,
>> -                                      drc_name);
>> +
>> +    ret = spapr_populate_pci_child_dt(pdev, p->fdt, offset, p->sphb);
>>       g_assert(!ret);
>>       if (ret) {
>>           return 0;
>> @@ -1033,7 +1091,6 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector 
>> *drc,
>>   {
>>       sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
>>       DeviceState *dev = DEVICE(pdev);
>> -    const char *drc_name = drck->get_name(drc);
>>       int fdt_start_offset = 0, fdt_size;
>>       sPAPRFDT s_fdt = {NULL, 0, NULL};
>>
>> @@ -1041,7 +1098,7 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector 
>> *drc,
>>           s_fdt.fdt = create_device_tree(&fdt_size);
>>           s_fdt.sphb = phb;
>>           s_fdt.node_off = 0;
>> -        fdt_start_offset = spapr_create_pci_child_dt(pdev, &s_fdt, 
>> drc_name);
>> +        fdt_start_offset = spapr_create_pci_child_dt(pdev, &s_fdt);
>>           if (!fdt_start_offset) {
>>               error_setg(errp, "Failed to create pci child device tree 
>> node");
>>               goto out;
>> @@ -1519,7 +1576,7 @@ static void spapr_populate_pci_devices_dt(PCIBus *bus, 
>> PCIDevice *pdev,
>>       int offset;
>>       sPAPRFDT s_fdt;
>>
>> -    offset = spapr_create_pci_child_dt(pdev, p, NULL);
>> +    offset = spapr_create_pci_child_dt(pdev, p);
>>       if (!offset) {
>>           error_report("Failed to create pci child device tree node");
>>           return;
>>
>
>
> -- 
> Alexey