Re: [Qemu-devel] [PATCH v4 4/4] spapr_pci: populate ibm,loc-code

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Alexey Kardashevskiy <aik@ozlabs.ru> writes:

> On 05/19/2015 02:51 PM, Nikunj A Dadhania wrote:
>> Alexey Kardashevskiy <aik@ozlabs.ru> writes:
>>
>>> On 05/07/2015 05:21 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 <nikunj@linux.vnet.ibm.com>
>>>> ---
>>>>    hw/ppc/spapr_pci.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++-------
>>>>    1 file changed, 86 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>>>> index 12f1b9c..d901007 100644
>>>> --- a/hw/ppc/spapr_pci.c
>>>> +++ b/hw/ppc/spapr_pci.c
>>>> @@ -769,6 +769,81 @@ static uint32_t spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
>>>>        return drck->get_index(drc);
>>>>    }
>>>>
>>>> +static bool spapr_phb_vfio_get_devspec_value(PCIDevice *pdev, char **value)
>>>
>>> Does it have to be a separate function?
>>
>> For better readability, i would prefer it this way.
>
> This is why I asked - I was having problems understanding the difference 
> between these two having 6 words names ;) Do not insist though.
>

This is what I have now, simplified:

+static char *spapr_phb_vfio_get_loc_code(sPAPRPHBState *sphb,  PCIDevice *pdev)
+{
+    char *path = NULL, *buf = NULL;
+    char *host = NULL;
+
+    /* 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)) {
+        goto err_out;
+    }
+    return buf;
+
+err_out:
+    g_free(path);
+    return NULL;
+}
+
+static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
+{
+    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
+        char *buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
+
+        /*
+         * In case of failures reading the loc-code, make it up
+         * indicating a vfio device
+         */
+        if (!buf) {
+            buf = g_strdup_printf("vfio_%s:%02d:%02d.%1d", pdev->name,
+                                  sphb->index, PCI_SLOT(pdev->devfn),
+                                  PCI_FUNC(pdev->devfn));
+        }
+        return buf;
+    } else {
+        return g_strdup_printf("qemu_%s:%02d:%02d.%1d", pdev->name,
+                               sphb->index, PCI_SLOT(pdev->devfn),
+                               PCI_FUNC(pdev->devfn));
+    }
+}
+

Regards
Nikunj