| Message ID | 20230829231912.4091958-13-volodymyr_babchuk@epam.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PCI devices passthrough on Arm, part 3 | expand |
On 30.08.2023 01:19, Volodymyr Babchuk wrote: > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > > Assign SBDF to the PCI devices being passed through with bus 0. > The resulting topology is where PCIe devices reside on the bus 0 of the > root complex itself (embedded endpoints). > This implementation is limited to 32 devices which are allowed on > a single PCI bus. > > Please note, that at the moment only function 0 of a multifunction > device can be passed through. > > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > --- > Since v9: > - Lock in add_virtual_device() replaced with ASSERT (thanks, Stewart) Also peeking at a few other patches where similar change remarks exist, I'm slightly confused by them: Is this submission v9 or v10? Jan
Hi Jan, Jan Beulich <jbeulich@suse.com> writes: > On 30.08.2023 01:19, Volodymyr Babchuk wrote: >> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> >> Assign SBDF to the PCI devices being passed through with bus 0. >> The resulting topology is where PCIe devices reside on the bus 0 of the >> root complex itself (embedded endpoints). >> This implementation is limited to 32 devices which are allowed on >> a single PCI bus. >> >> Please note, that at the moment only function 0 of a multifunction >> device can be passed through. >> >> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> --- >> Since v9: >> - Lock in add_virtual_device() replaced with ASSERT (thanks, Stewart) > > Also peeking at a few other patches where similar change remarks exist, > I'm slightly confused by them: Is this submission v9 or v10? Sorry, looks like I was using wrong wording. This is submission v9. Under "Since v9" I meant "in v9 and further".
On Tue, Aug 29, 2023 at 11:19:46PM +0000, Volodymyr Babchuk wrote: > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > > Assign SBDF to the PCI devices being passed through with bus 0. > The resulting topology is where PCIe devices reside on the bus 0 of the > root complex itself (embedded endpoints). > This implementation is limited to 32 devices which are allowed on > a single PCI bus. > > Please note, that at the moment only function 0 of a multifunction > device can be passed through. > > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > --- > Since v9: > - Lock in add_virtual_device() replaced with ASSERT (thanks, Stewart) > Since v8: > - Added write lock in add_virtual_device > Since v6: > - re-work wrt new locking scheme > - OT: add ASSERT(pcidevs_write_locked()); to add_virtual_device() > Since v5: > - s/vpci_add_virtual_device/add_virtual_device and make it static > - call add_virtual_device from vpci_assign_device and do not use > REGISTER_VPCI_INIT machinery > - add pcidevs_locked ASSERT > - use DECLARE_BITMAP for vpci_dev_assigned_map > Since v4: > - moved and re-worked guest sbdf initializers > - s/set_bit/__set_bit > - s/clear_bit/__clear_bit > - minor comment fix s/Virtual/Guest/ > - added VPCI_MAX_VIRT_DEV constant (PCI_SLOT(~0) + 1) which will be used > later for counting the number of MMIO handlers required for a guest > (Julien) > Since v3: > - make use of VPCI_INIT > - moved all new code to vpci.c which belongs to it > - changed open-coded 31 to PCI_SLOT(~0) > - added comments and code to reject multifunction devices with > functions other than 0 > - updated comment about vpci_dev_next and made it unsigned int > - implement roll back in case of error while assigning/deassigning devices > - s/dom%pd/%pd > Since v2: > - remove casts that are (a) malformed and (b) unnecessary > - add new line for better readability > - remove CONFIG_HAS_VPCI_GUEST_SUPPORT ifdef's as the relevant vPCI > functions are now completely gated with this config > - gate common code with CONFIG_HAS_VPCI_GUEST_SUPPORT > New in v2 > --- > xen/drivers/vpci/vpci.c | 69 +++++++++++++++++++++++++++++++++++++++++ > xen/include/xen/sched.h | 8 +++++ > xen/include/xen/vpci.h | 11 +++++++ > 3 files changed, 88 insertions(+) > > diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c > index 412685f41d..b284f95e05 100644 > --- a/xen/drivers/vpci/vpci.c > +++ b/xen/drivers/vpci/vpci.c > @@ -36,6 +36,54 @@ extern vpci_register_init_t *const __start_vpci_array[]; > extern vpci_register_init_t *const __end_vpci_array[]; > #define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array) > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > +static int add_virtual_device(struct pci_dev *pdev) > +{ > + struct domain *d = pdev->domain; > + pci_sbdf_t sbdf = { 0 }; > + unsigned long new_dev_number; > + > + if ( is_hardware_domain(d) ) > + return 0; > + > + ASSERT(pcidevs_locked() && rw_is_write_locked(&pdev->domain->pci_lock)); Do you need to check for pcidevs here? I would think d->pci_lock would be enough to protect the virtual allocation device bitmap. > + > + /* > + * Each PCI bus supports 32 devices/slots at max or up to 256 when > + * there are multi-function ones which are not yet supported. > + */ > + if ( pdev->info.is_extfn ) I think you are missing a !pdev->info.is_virtfn, as is_extfn && is_virtfn mean the PF it's an extended function, but not the VF we are trying to passthrough. > + { > + gdprintk(XENLOG_ERR, "%pp: only function 0 passthrough supported\n", > + &pdev->sbdf); > + return -EOPNOTSUPP; > + } > + new_dev_number = find_first_zero_bit(d->vpci_dev_assigned_map, > + VPCI_MAX_VIRT_DEV); > + if ( new_dev_number >= VPCI_MAX_VIRT_DEV ) The > is not required, as find_first_zero_bit() will return VPCI_MAX_VIRT_DEV if the bitmap is all set. > + { > + write_unlock(&pdev->domain->pci_lock); > + return -ENOSPC; > + } > + > + __set_bit(new_dev_number, &d->vpci_dev_assigned_map); > + > + /* > + * Both segment and bus number are 0: > + * - we emulate a single host bridge for the guest, e.g. segment 0 > + * - with bus 0 the virtual devices are seen as embedded > + * endpoints behind the root complex > + * > + * TODO: add support for multi-function devices. > + */ > + sbdf.devfn = PCI_DEVFN(new_dev_number, 0); > + pdev->vpci->guest_sbdf = sbdf; You could avoid the local sbdf variable and just use PCI_SBDF(0, 0, new_dev_number, 0); > + > + return 0; > +} > + > +#endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */ > + > void vpci_deassign_device(struct pci_dev *pdev) > { > unsigned int i; > @@ -46,6 +94,16 @@ void vpci_deassign_device(struct pci_dev *pdev) > return; > > spin_lock(&pdev->vpci->lock); > + > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + if ( pdev->vpci->guest_sbdf.sbdf != ~0 ) > + { > + __clear_bit(pdev->vpci->guest_sbdf.dev, > + &pdev->domain->vpci_dev_assigned_map); > + pdev->vpci->guest_sbdf.sbdf = ~0; > + } > +#endif There's no need to set sbdf = ~0 as vpci is just about to be freed. > + > while ( !list_empty(&pdev->vpci->handlers) ) > { > struct vpci_register *r = list_first_entry(&pdev->vpci->handlers, > @@ -101,6 +159,13 @@ int vpci_assign_device(struct pci_dev *pdev) > INIT_LIST_HEAD(&pdev->vpci->handlers); > spin_lock_init(&pdev->vpci->lock); > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + pdev->vpci->guest_sbdf.sbdf = ~0; > + rc = add_virtual_device(pdev); > + if ( rc ) > + goto out; > +#endif > + > for ( i = 0; i < NUM_VPCI_INIT; i++ ) > { > rc = __start_vpci_array[i](pdev); > @@ -108,11 +173,15 @@ int vpci_assign_device(struct pci_dev *pdev) > break; > } > > +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT > + out: > +#endif That's ugly, can you use the __maybe_unused attribute with a label? > if ( rc ) > vpci_deassign_device(pdev); > > return rc; > } > + Spurious change. Thanks, Roger.
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c index 412685f41d..b284f95e05 100644 --- a/xen/drivers/vpci/vpci.c +++ b/xen/drivers/vpci/vpci.c @@ -36,6 +36,54 @@ extern vpci_register_init_t *const __start_vpci_array[]; extern vpci_register_init_t *const __end_vpci_array[]; #define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array) +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT +static int add_virtual_device(struct pci_dev *pdev) +{ + struct domain *d = pdev->domain; + pci_sbdf_t sbdf = { 0 }; + unsigned long new_dev_number; + + if ( is_hardware_domain(d) ) + return 0; + + ASSERT(pcidevs_locked() && rw_is_write_locked(&pdev->domain->pci_lock)); + + /* + * Each PCI bus supports 32 devices/slots at max or up to 256 when + * there are multi-function ones which are not yet supported. + */ + if ( pdev->info.is_extfn ) + { + gdprintk(XENLOG_ERR, "%pp: only function 0 passthrough supported\n", + &pdev->sbdf); + return -EOPNOTSUPP; + } + new_dev_number = find_first_zero_bit(d->vpci_dev_assigned_map, + VPCI_MAX_VIRT_DEV); + if ( new_dev_number >= VPCI_MAX_VIRT_DEV ) + { + write_unlock(&pdev->domain->pci_lock); + return -ENOSPC; + } + + __set_bit(new_dev_number, &d->vpci_dev_assigned_map); + + /* + * Both segment and bus number are 0: + * - we emulate a single host bridge for the guest, e.g. segment 0 + * - with bus 0 the virtual devices are seen as embedded + * endpoints behind the root complex + * + * TODO: add support for multi-function devices. + */ + sbdf.devfn = PCI_DEVFN(new_dev_number, 0); + pdev->vpci->guest_sbdf = sbdf; + + return 0; +} + +#endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */ + void vpci_deassign_device(struct pci_dev *pdev) { unsigned int i; @@ -46,6 +94,16 @@ void vpci_deassign_device(struct pci_dev *pdev) return; spin_lock(&pdev->vpci->lock); + +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT + if ( pdev->vpci->guest_sbdf.sbdf != ~0 ) + { + __clear_bit(pdev->vpci->guest_sbdf.dev, + &pdev->domain->vpci_dev_assigned_map); + pdev->vpci->guest_sbdf.sbdf = ~0; + } +#endif + while ( !list_empty(&pdev->vpci->handlers) ) { struct vpci_register *r = list_first_entry(&pdev->vpci->handlers, @@ -101,6 +159,13 @@ int vpci_assign_device(struct pci_dev *pdev) INIT_LIST_HEAD(&pdev->vpci->handlers); spin_lock_init(&pdev->vpci->lock); +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT + pdev->vpci->guest_sbdf.sbdf = ~0; + rc = add_virtual_device(pdev); + if ( rc ) + goto out; +#endif + for ( i = 0; i < NUM_VPCI_INIT; i++ ) { rc = __start_vpci_array[i](pdev); @@ -108,11 +173,15 @@ int vpci_assign_device(struct pci_dev *pdev) break; } +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT + out: +#endif if ( rc ) vpci_deassign_device(pdev); return rc; } + #endif /* __XEN__ */ static int vpci_register_cmp(const struct vpci_register *r1, diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index 535a81fe90..0aafe19a51 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -461,6 +461,14 @@ struct domain #ifdef CONFIG_HAS_PCI struct list_head pdev_list; rwlock_t pci_lock; +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT + /* + * The bitmap which shows which device numbers are already used by the + * virtual PCI bus topology and is used to assign a unique SBDF to the + * next passed through virtual PCI device. + */ + DECLARE_BITMAP(vpci_dev_assigned_map, VPCI_MAX_VIRT_DEV); +#endif #endif #ifdef CONFIG_HAS_PASSTHROUGH diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h index f67d848616..58304523ab 100644 --- a/xen/include/xen/vpci.h +++ b/xen/include/xen/vpci.h @@ -21,6 +21,13 @@ typedef int vpci_register_init_t(struct pci_dev *dev); #define VPCI_ECAM_BDF(addr) (((addr) & 0x0ffff000) >> 12) +/* + * Maximum number of devices supported by the virtual bus topology: + * each PCI bus supports 32 devices/slots at max or up to 256 when + * there are multi-function ones which are not yet supported. + */ +#define VPCI_MAX_VIRT_DEV (PCI_SLOT(~0) + 1) + #define REGISTER_VPCI_INIT(x, p) \ static vpci_register_init_t *const x##_entry \ __used_section(".data.vpci." p) = x @@ -155,6 +162,10 @@ struct vpci { struct vpci_arch_msix_entry arch; } entries[]; } *msix; +#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT + /* Guest SBDF of the device. */ + pci_sbdf_t guest_sbdf; +#endif #endif };