From: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>
When running in a stubdomain, the config space access via sysfs needs to
use BDF as seen inside stubdomain (connected via xen-pcifront), which is
different from the real BDF. For other purposes (hypercall parameters
etc), the real BDF needs to be used.
Get the in-stubdomain BDF by looking up relevant PV PCI xenstore
entries.
Signed-off-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>
Reviewed-by: Anthony PERARD <anthony.per...@citrix.com>
Message-Id:
<35049e99da634a74578a1ff2cb3ae4cc436ede33.1711506237.git-series.marma...@invisiblethingslab.com>
Signed-off-by: Anthony PERARD <anth...@xenproject.org>
---
hw/xen/xen-host-pci-device.c | 76 +++++++++++++++++++++++++++++++++++-
hw/xen/xen-host-pci-device.h | 6 +++
2 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c
index 8c6e9a1716..eaf32f2710 100644
--- a/hw/xen/xen-host-pci-device.c
+++ b/hw/xen/xen-host-pci-device.c
@@ -9,6 +9,8 @@
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/cutils.h"
+#include "hw/xen/xen-legacy-backend.h"
+#include "hw/xen/xen-bus-helper.h"
#include "xen-host-pci-device.h"
#define XEN_HOST_PCI_MAX_EXT_CAP \
@@ -33,13 +35,73 @@
#define IORESOURCE_PREFETCH 0x00001000 /* No side effects */
#define IORESOURCE_MEM_64 0x00100000
+/*
+ * Non-passthrough (dom0) accesses are local PCI devices and use the given BDF
+ * Passthough (stubdom) accesses are through PV frontend PCI device. Those
+ * either have a BDF identical to the backend's BDF (xen-backend.passthrough=1)
+ * or a local virtual BDF (xen-backend.passthrough=0)
+ *
+ * We are always given the backend's BDF and need to lookup the appropriate
+ * local BDF for sysfs access.
+ */
+static void xen_host_pci_fill_local_addr(XenHostPCIDevice *d, Error **errp)
+{
+ unsigned int num_devs, len, i;
+ unsigned int domain, bus, dev, func;
+ char *be_path = NULL;
+ char path[16];
+
+ be_path = qemu_xen_xs_read(xenstore, 0, "device/pci/0/backend", &len);
+ if (!be_path) {
+ error_setg(errp, "Failed to read device/pci/0/backend");
+ goto out;
+ }
+
+ if (xs_node_scanf(xenstore, 0, be_path, "num_devs", NULL,
+ "%d", &num_devs) != 1) {
+ error_setg(errp, "Failed to read or parse %s/num_devs", be_path);
+ goto out;
+ }
+
+ for (i = 0; i < num_devs; i++) {
+ snprintf(path, sizeof(path), "dev-%d", i);
+ if (xs_node_scanf(xenstore, 0, be_path, path, NULL,
+ "%x:%x:%x.%x", &domain, &bus, &dev, &func) != 4) {
+ error_setg(errp, "Failed to read or parse %s/%s", be_path, path);
+ goto out;
+ }
+ if (domain != d->domain ||
+ bus != d->bus ||
+ dev != d->dev ||
+ func != d->func)
+ continue;
+ snprintf(path, sizeof(path), "vdev-%d", i);
+ if (xs_node_scanf(xenstore, 0, be_path, path, NULL,
+ "%x:%x:%x.%x", &domain, &bus, &dev, &func) != 4) {
+ error_setg(errp, "Failed to read or parse %s/%s", be_path, path);
+ goto out;
+ }
+ d->local_domain = domain;
+ d->local_bus = bus;
+ d->local_dev = dev;
+ d->local_func = func;
+ goto out;
+ }
+ error_setg(errp, "Failed to find PCI device %x:%x:%x.%x in xenstore",
+ d->domain, d->bus, d->dev, d->func);
+
+out:
+ free(be_path);
+}
+
static void xen_host_pci_sysfs_path(const XenHostPCIDevice *d,
const char *name, char *buf, ssize_t size)
{
int rc;
rc = snprintf(buf, size, "/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
- d->domain, d->bus, d->dev, d->func, name);
+ d->local_domain, d->local_bus, d->local_dev, d->local_func,
+ name);
assert(rc >= 0 && rc < size);
}
@@ -342,6 +404,18 @@ void xen_host_pci_device_get(XenHostPCIDevice *d, uint16_t
domain,
d->dev = dev;
d->func = func;
+ if (xen_is_stubdomain) {
+ xen_host_pci_fill_local_addr(d, errp);
+ if (*errp) {
+ goto error;
+ }
+ } else {
+ d->local_domain = d->domain;
+ d->local_bus = d->bus;
+ d->local_dev = d->dev;
+ d->local_func = d->func;
+ }
+
xen_host_pci_config_open(d, errp);
if (*errp) {
goto error;
diff --git a/hw/xen/xen-host-pci-device.h b/hw/xen/xen-host-pci-device.h
index 4d8d34ecb0..270dcb27f7 100644
--- a/hw/xen/xen-host-pci-device.h
+++ b/hw/xen/xen-host-pci-device.h
@@ -23,6 +23,12 @@ typedef struct XenHostPCIDevice {
uint8_t dev;
uint8_t func;
+ /* different from the above in case of stubdomain */
+ uint16_t local_domain;
+ uint8_t local_bus;
+ uint8_t local_dev;
+ uint8_t local_func;
+
uint16_t vendor_id;
uint16_t device_id;
uint32_t class_code;
--
Anthony PERARD
