Michael S. Tsirkin
2018-Apr-03 12:25 UTC
[RFC PATCH 1/3] qemu: virtio-bypass should explicitly bind to a passthrough device
On Sun, Apr 01, 2018 at 05:13:08AM -0400, Si-Wei Liu wrote:> @@ -896,6 +898,68 @@ void qmp_device_del(const char *id, Error **errp) > } > } > > +int pci_get_busdevfn_by_id(const char *id, uint16_t *busnr, > + uint16_t *devfn, Error **errp) > +{ > + uint16_t busnum = 0, slot = 0, func = 0; > + const char *pc, *pd, *pe; > + Error *local_err = NULL; > + ObjectClass *class; > + char value[1024]; > + BusState *bus; > + uint64_t u64; > + > + if (!(pc = strchr(id, ':'))) { > + error_setg(errp, "Invalid id: backup=%s, " > + "correct format should be backup=" > + "'<bus-id>:<slot>[.<function>]'", id); > + return -1; > + } > + get_opt_name(value, sizeof(value), id, ':'); > + if (pc != id + 1) { > + bus = qbus_find(value, errp); > + if (!bus) > + return -1; > + > + class = object_get_class(OBJECT(bus)); > + if (class != object_class_by_name(TYPE_PCI_BUS) && > + class != object_class_by_name(TYPE_PCIE_BUS)) { > + error_setg(errp, "%s is not a device on pci bus", id); > + return -1; > + } > + busnum = (uint16_t)pci_bus_num(PCI_BUS(bus)); > + }pci_bus_num is almost always a bug if not done within a context of a PCI host, bridge, etc. In particular this will not DTRT if run before guest assigns bus numbers.> + > + if (!devfn) > + goto out; > + > + pd = strchr(pc, '.'); > + pe = get_opt_name(value, sizeof(value), pc + 1, '.'); > + if (pe != pc + 1) { > + parse_option_number("slot", value, &u64, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + return -1; > + } > + slot = (uint16_t)u64; > + } > + if (pd && *(pd + 1) != '\0') { > + parse_option_number("function", pd, &u64, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + return -1; > + } > + func = (uint16_t)u64; > + } > + > +out: > + if (busnr) > + *busnr = busnum; > + if (devfn) > + *devfn = ((slot & 0x1F) << 3) | (func & 0x7); > + return 0; > +} > + > BlockBackend *blk_by_qdev_id(const char *id, Error **errp) > { > DeviceState *dev; > -- > 1.8.3.1
Siwei Liu
2018-Apr-04 08:02 UTC
[virtio-dev] Re: [RFC PATCH 1/3] qemu: virtio-bypass should explicitly bind to a passthrough device
On Tue, Apr 3, 2018 at 5:25 AM, Michael S. Tsirkin <mst at redhat.com> wrote:> On Sun, Apr 01, 2018 at 05:13:08AM -0400, Si-Wei Liu wrote: >> @@ -896,6 +898,68 @@ void qmp_device_del(const char *id, Error **errp) >> } >> } >> >> +int pci_get_busdevfn_by_id(const char *id, uint16_t *busnr, >> + uint16_t *devfn, Error **errp) >> +{ >> + uint16_t busnum = 0, slot = 0, func = 0; >> + const char *pc, *pd, *pe; >> + Error *local_err = NULL; >> + ObjectClass *class; >> + char value[1024]; >> + BusState *bus; >> + uint64_t u64; >> + >> + if (!(pc = strchr(id, ':'))) { >> + error_setg(errp, "Invalid id: backup=%s, " >> + "correct format should be backup=" >> + "'<bus-id>:<slot>[.<function>]'", id); >> + return -1; >> + } >> + get_opt_name(value, sizeof(value), id, ':'); >> + if (pc != id + 1) { >> + bus = qbus_find(value, errp); >> + if (!bus) >> + return -1; >> + >> + class = object_get_class(OBJECT(bus)); >> + if (class != object_class_by_name(TYPE_PCI_BUS) && >> + class != object_class_by_name(TYPE_PCIE_BUS)) { >> + error_setg(errp, "%s is not a device on pci bus", id); >> + return -1; >> + } >> + busnum = (uint16_t)pci_bus_num(PCI_BUS(bus)); >> + } > > pci_bus_num is almost always a bug if not done within > a context of a PCI host, bridge, etc. > > In particular this will not DTRT if run before guest assigns bus > numbers. >I was seeking means to reserve a specific pci bus slot from drivers, and update the driver when guest assigns the bus number but it seems there's no low-hanging fruits. Because of that reason the bus_num is only obtained until it's really needed (during get_config) and I assume at that point the pci bus assignment is already done. I know the current one is not perfect, but we need that information (PCI bus:slot.func number) to name the guest device correctly. Regards, -Siwei> >> + >> + if (!devfn) >> + goto out; >> + >> + pd = strchr(pc, '.'); >> + pe = get_opt_name(value, sizeof(value), pc + 1, '.'); >> + if (pe != pc + 1) { >> + parse_option_number("slot", value, &u64, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + return -1; >> + } >> + slot = (uint16_t)u64; >> + } >> + if (pd && *(pd + 1) != '\0') { >> + parse_option_number("function", pd, &u64, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + return -1; >> + } >> + func = (uint16_t)u64; >> + } >> + >> +out: >> + if (busnr) >> + *busnr = busnum; >> + if (devfn) >> + *devfn = ((slot & 0x1F) << 3) | (func & 0x7); >> + return 0; >> +} >> + >> BlockBackend *blk_by_qdev_id(const char *id, Error **errp) >> { >> DeviceState *dev; >> -- >> 1.8.3.1 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe at lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help at lists.oasis-open.org >
Paolo Bonzini
2018-Apr-05 15:31 UTC
[virtio-dev] Re: [RFC PATCH 1/3] qemu: virtio-bypass should explicitly bind to a passthrough device
On 04/04/2018 10:02, Siwei Liu wrote:>> pci_bus_num is almost always a bug if not done within >> a context of a PCI host, bridge, etc. >> >> In particular this will not DTRT if run before guest assigns bus >> numbers. >> > I was seeking means to reserve a specific pci bus slot from drivers, > and update the driver when guest assigns the bus number but it seems > there's no low-hanging fruits. Because of that reason the bus_num is > only obtained until it's really needed (during get_config) and I > assume at that point the pci bus assignment is already done. I know > the current one is not perfect, but we need that information (PCI > bus:slot.func number) to name the guest device correctly.Can you use the -device "id", and look it up as devices = container_get(qdev_get_machine(), "/peripheral"); return object_resolve_path_component(devices, id); ? Thanks, Paolo