[Qemu-devel] [QEMU][RFC PATCH 4/6] xen-pci: Register PCI in Xen

[Julien Grall]

QEMU will now register PCI in Xen. It will usefull to forward
IO config space to the right QEMU.

Before to register a PCI device, QEMU will check with XenStore if it is
autorized to register the PCI associate to a given BDF.

Signed-off-by: Julien Grall <address@hidden>
---
 hw/pci.c  |    6 +++++
 xen-all.c |   70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 0 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index bf046bf..4df4449 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -31,6 +31,7 @@
 #include "loader.h"
 #include "range.h"
 #include "qmp-commands.h"
+#include "xen.h"
 
 //#define DEBUG_PCI
 #ifdef DEBUG_PCI
@@ -764,6 +765,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev, PCIBus *bus,
     pci_dev->devfn = devfn;
     pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
     pci_dev->irq_state = 0;
+
+    if (xen_enabled() && xen_register_pcidev(pci_dev)) {
+        return NULL;
+    }
+
     pci_config_alloc(pci_dev);
 
     pci_config_set_vendor_id(pci_dev->config, pc->vendor_id);
diff --git a/xen-all.c b/xen-all.c
index 366bafe..2f5405c 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -107,6 +107,76 @@ void xen_piix3_set_irq(void *opaque, int irq_num, int 
level)
                               irq_num & 3, level);
 }
 
+static uint32_t str_to_bdf(const char *str)
+{
+    /* We assume that bdf is valid */
+    char *buf;
+    uint32_t bdf;
+    uint32_t tmp;
+
+    bdf = strtol(str, &buf, 16);
+    buf++;
+
+    str = buf;
+    tmp = strtol(str, &buf, 16);
+    bdf = (bdf << 16) | (tmp << 11);
+    buf++;
+
+    str = buf;
+    tmp = strtol(str, &buf, 16);
+    bdf = bdf | (tmp << 8);
+
+    return bdf;
+}
+
+int xen_register_pcidev(PCIDevice *pci_dev)
+{
+    struct xs_handle *xs = NULL;
+    uint32_t bdf = 0;
+    uint32_t allowed_bdf = 0;
+    char **dir;
+    char path[50];
+    unsigned int nb;
+    unsigned int i;
+    unsigned int len;
+    char *str;
+    int rc = 0;
+
+
+    /* Fix : missing bus id to be more generic */
+    bdf |= pci_dev->devfn << 8;
+
+    xs = xs_open(0);
+    if (!xs) {
+        fprintf(stderr, "pci_register: Unable to open xenstore\n");
+        return 1;
+    }
+
+    snprintf(path, sizeof (path), "/local/domain/%u/image/dms/%u/pci",
+             xen_domid, xen_dmid);
+
+    dir = xs_directory(xs, XBT_NULL, path, &nb);
+    if (dir) {
+        for (i = 0; i < nb; i++) {
+            snprintf(path, sizeof (path), 
"/local/domain/%u/image/dms/%u/pci/%s",
+                     xen_domid, xen_dmid, dir[i]);
+            str = xs_read(xs, XBT_NULL, path, &len);
+            allowed_bdf = str_to_bdf(str);
+            free(str);
+            if (bdf == allowed_bdf)
+            {
+                rc = xc_hvm_register_pcidev(xen_xc, xen_domid, serverid, bdf);
+                break;
+            }
+        }
+        free(dir);
+    }
+
+    xs_close(xs);
+
+    return rc;
+}
+
 void xen_piix_pci_write_config_client(uint32_t address, uint32_t val, int len)
 {
     int i;
-- 
Julien Grall