| Message ID | 20240305191312.321127-2-marmarek@invisiblethingslab.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] hw/xen: detect when running inside stubdomain | expand |
On Tue, Mar 5, 2024 at 2:13 PM Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> wrote: > > From: Frédéric Pierret (fepitre) <frederic.pierret@qubes-os.org> Needs to be changed to Marek. > 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 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 | 69 +++++++++++++++++++++++++++++++++++- > hw/xen/xen-host-pci-device.h | 6 ++++ > 2 files changed, 74 insertions(+), 1 deletion(-) > > diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c > index 8c6e9a1716..8ea2a5a4af 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 +35,67 @@ > #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[80]; path is now only used for dev/vdev-%d, so 80 could be reduced. > + > + be_path = qemu_xen_xs_read(xenstore, 0, "device/pci/0/backend", &len); > + if (!be_path) error_setg() here? > + 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\n", 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\n", 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\n", 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 here in case we exited the loop without finding a match? Thanks, Jason > + > +out: > + free(be_path); > +} > +
First things first, could you fix the coding style? Run something like `./scripts/checkpatch.pl @^..` or `./scripts/checkpatch.pl master..`. Patchew might have run that for you if the patch series had a cover letter. On Tue, Mar 05, 2024 at 08:12:30PM +0100, Marek Marczykowski-Górecki wrote: > diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c > index 8c6e9a1716..8ea2a5a4af 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" I'd like to avoid this header here, that would be complicated at the moment, as the global variable `xenstore` would be missing. So for now, that's fine. I guess that could be rework if something like Philippe talked about at https://lore.kernel.org/qemu-devel/429a5a27-21b9-45bd-a1a6-a1c2ccc484c9@linaro.org/ materialise. Beside the coding style, the patch looks file. Thanks,
diff --git a/hw/xen/xen-host-pci-device.c b/hw/xen/xen-host-pci-device.c index 8c6e9a1716..8ea2a5a4af 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 +35,67 @@ #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[80]; + + be_path = qemu_xen_xs_read(xenstore, 0, "device/pci/0/backend", &len); + if (!be_path) + 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\n", 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\n", 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\n", be_path, path); + goto out; + } + d->local_domain = domain; + d->local_bus = bus; + d->local_dev = dev; + d->local_func = func; + goto out; + } + +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 +398,17 @@ 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;