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


From: Alexey Kardashevskiy
Subject: Re: [Qemu-devel] [PATCH v4 4/4] spapr_pci: populate ibm,loc-code
Date: Tue, 19 May 2015 17:41:58 +1000
User-agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0

On 05/19/2015 04:56 PM, Nikunj A Dadhania wrote:
Alexey Kardashevskiy <address@hidden> writes:

On 05/19/2015 02:51 PM, Nikunj A Dadhania wrote:
Alexey Kardashevskiy <address@hidden> 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 <address@hidden>
---
    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));
+    }
+}


I'd do this but I do not insist :)

static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
{
    char *buf;
    char *devtype = "qemu";

    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
        buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
        if (buf) {
            return buf;
        }
        devtype = "vfio";
    }

    /*
     * In case of failures reading the loc-code, make it up
     * indicating a vfio device
     */
    buf = g_strdup_printf("%s_%s:%02d:%02d.%1d",
                          devtype, pdev->name,
                          sphb->index, PCI_SLOT(pdev->devfn),
                          PCI_FUNC(pdev->devfn));
    return buf;
}



--
Alexey



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