* [PATCH v3 1/2] hw/xen: detect when running inside stubdomain
2024-03-27 3:05 [PATCH v3 0/2] Changes necessary to work inside Xen device model stubdomain Marek Marczykowski-Górecki
@ 2024-03-27 3:05 ` Marek Marczykowski-Górecki
2024-04-03 15:38 ` Anthony PERARD
2024-03-27 3:05 ` [PATCH v3 2/2] xen: fix stubdom PCI addr Marek Marczykowski-Górecki
1 sibling, 1 reply; 5+ messages in thread
From: Marek Marczykowski-Górecki @ 2024-03-27 3:05 UTC (permalink / raw)
To: qemu-devel
Cc: Marek Marczykowski-Górecki, Stefano Stabellini,
Anthony Perard, Paul Durrant, Paolo Bonzini, Richard Henderson,
Eduardo Habkost, Michael S. Tsirkin, Marcel Apfelbaum,
open list:X86 Xen CPUs
Introduce global xen_is_stubdomain variable when qemu is running inside
a stubdomain instead of dom0. This will be relevant for subsequent
patches, as few things like accessing PCI config space need to be done
differently.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
Changes in v3:
- move to xen_hvm_init_pc()
- coding style
Changes in v2:
- use sigend int for domid to match xenstore_read_int() types
- fix code style
---
hw/i386/xen/xen-hvm.c | 22 ++++++++++++++++++++++
include/hw/xen/xen.h | 1 +
system/globals.c | 1 +
3 files changed, 24 insertions(+)
diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index 7745cb3..3291c17 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -583,6 +583,26 @@ static void xen_wakeup_notifier(Notifier *notifier, void *data)
xc_set_hvm_param(xen_xc, xen_domid, HVM_PARAM_ACPI_S_STATE, 0);
}
+static bool xen_check_stubdomain(struct xs_handle *xsh)
+{
+ char *dm_path = g_strdup_printf(
+ "/local/domain/%d/image/device-model-domid", xen_domid);
+ char *val;
+ int32_t dm_domid;
+ bool is_stubdom = false;
+
+ val = xs_read(xsh, 0, dm_path, NULL);
+ if (val) {
+ if (sscanf(val, "%d", &dm_domid) == 1) {
+ is_stubdom = dm_domid != 0;
+ }
+ free(val);
+ }
+
+ g_free(dm_path);
+ return is_stubdom;
+}
+
void xen_hvm_init_pc(PCMachineState *pcms, MemoryRegion **ram_memory)
{
MachineState *ms = MACHINE(pcms);
@@ -595,6 +615,8 @@ void xen_hvm_init_pc(PCMachineState *pcms, MemoryRegion **ram_memory)
xen_register_ioreq(state, max_cpus, &xen_memory_listener);
+ xen_is_stubdomain = xen_check_stubdomain(state->xenstore);
+
QLIST_INIT(&xen_physmap);
xen_read_physmap(state);
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index 37ecc91..ecb89ec 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -36,6 +36,7 @@ enum xen_mode {
extern uint32_t xen_domid;
extern enum xen_mode xen_mode;
extern bool xen_domid_restrict;
+extern bool xen_is_stubdomain;
int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num);
int xen_set_pci_link_route(uint8_t link, uint8_t irq);
diff --git a/system/globals.c b/system/globals.c
index e353584..d602a04 100644
--- a/system/globals.c
+++ b/system/globals.c
@@ -60,6 +60,7 @@ bool qemu_uuid_set;
uint32_t xen_domid;
enum xen_mode xen_mode = XEN_DISABLED;
bool xen_domid_restrict;
+bool xen_is_stubdomain;
struct evtchn_backend_ops *xen_evtchn_ops;
struct gnttab_backend_ops *xen_gnttab_ops;
struct foreignmem_backend_ops *xen_foreignmem_ops;
--
git-series 0.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v3 2/2] xen: fix stubdom PCI addr
2024-03-27 3:05 [PATCH v3 0/2] Changes necessary to work inside Xen device model stubdomain Marek Marczykowski-Górecki
2024-03-27 3:05 ` [PATCH v3 1/2] hw/xen: detect when running inside stubdomain Marek Marczykowski-Górecki
@ 2024-03-27 3:05 ` Marek Marczykowski-Górecki
2024-04-03 15:43 ` Anthony PERARD
1 sibling, 1 reply; 5+ messages in thread
From: Marek Marczykowski-Górecki @ 2024-03-27 3:05 UTC (permalink / raw)
To: qemu-devel
Cc: Marek Marczykowski-Górecki, Stefano Stabellini,
Anthony Perard, Paul Durrant, open list:X86 Xen CPUs
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 <marmarek@invisiblethingslab.com>
---
Changes in v3:
- reduce 'path' size
- add two missing error_setg() calls
- coding style
Changes in v2:
- use xs_node_scanf
- use %d instead of %u to read values written as %d
- add a comment from another iteration of this patch by Jason Andryuk
---
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 8c6e9a1..eaf32f2 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 4d8d34e..270dcb2 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;
--
git-series 0.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread