[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [RFC KERNEL PATCH v2 1/3] xen/pci: Add xen_reset_device_state function
On 11/30/23 02:03, Chen, Jiqian wrote: > > On 2023/11/30 11:46, Stefano Stabellini wrote: >> On Fri, 24 Nov 2023, Jiqian Chen wrote: >>> When device on dom0 side has been reset, the vpci on Xen side >>> won't get notification, so that the cached state in vpci is >>> all out of date with the real device state. >>> To solve that problem, this patch add a function to clear all >>> vpci device state when device is reset on dom0 side. >>> >>> And call that function in pcistub_init_device. Because when >>> we use "pci-assignable-add" to assign a passthrough device in >>> Xen, it will reset passthrough device and the vpci state will >>> out of date, and then device will fail to restore bar state. >>> >>> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx> >>> Signed-off-by: Huang Rui <ray.huang@xxxxxxx> >>> --- >>> drivers/xen/pci.c | 12 ++++++++++++ >>> drivers/xen/xen-pciback/pci_stub.c | 3 +++ >>> include/xen/interface/physdev.h | 2 ++ >>> include/xen/pci.h | 6 ++++++ >>> 4 files changed, 23 insertions(+) >>> >>> diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c >>> index 72d4e3f193af..e9b30bc09139 100644 >>> --- a/drivers/xen/pci.c >>> +++ b/drivers/xen/pci.c >>> @@ -177,6 +177,18 @@ static int xen_remove_device(struct device *dev) >>> return r; >>> } >>> >>> +int xen_reset_device_state(const struct pci_dev *dev) >>> +{ >>> + struct physdev_pci_device device = { >>> + .seg = pci_domain_nr(dev->bus), >>> + .bus = dev->bus->number, >>> + .devfn = dev->devfn >>> + }; >>> + >>> + return HYPERVISOR_physdev_op(PHYSDEVOP_pci_device_state_reset, &device); >>> +} >>> +EXPORT_SYMBOL_GPL(xen_reset_device_state); >>> + >>> static int xen_pci_notifier(struct notifier_block *nb, >>> unsigned long action, void *data) >>> { >>> diff --git a/drivers/xen/xen-pciback/pci_stub.c >>> b/drivers/xen/xen-pciback/pci_stub.c >>> index e34b623e4b41..5a96b6c66c07 100644 >>> --- a/drivers/xen/xen-pciback/pci_stub.c >>> +++ b/drivers/xen/xen-pciback/pci_stub.c >>> @@ -421,6 +421,9 @@ static int pcistub_init_device(struct pci_dev *dev) >>> else { >>> dev_dbg(&dev->dev, "resetting (FLR, D3, etc) the device\n"); >>> __pci_reset_function_locked(dev); >>> + err = xen_reset_device_state(dev); >>> + if (err) >>> + goto config_release; >> >> Older versions of Xen won't have the hypercall >> PHYSDEVOP_pci_device_state_reset implemented. I think we should do >> something like: >> >> if (err && xen_pvh_domain()) >> goto config_release; >> >> >> Or even: >> >> if (xen_pvh_domain()) { >> err = xen_reset_device_state(dev); >> if (err) >> goto config_release; >> } >> >> depending on whether we want to call xen_reset_device_state also for PV >> guests or not. I am assuming we don't want to error out on failure such >> as -ENOENT for PV guests. > Yes, only for PVH dom0, I will add the condition in next version. Thank you! We will want to call xen_reset_device_state() for Arm dom0, too, so checking xen_pvh_domain() alone is not sufficient. I suggest instead to check !xen_pv_domain(). > >> >> >>> pci_restore_state(dev); >>> } >>> /* Now disable the device (this also ensures some private device >>> diff --git a/include/xen/interface/physdev.h >>> b/include/xen/interface/physdev.h >>> index a237af867873..231526f80f6c 100644 >>> --- a/include/xen/interface/physdev.h >>> +++ b/include/xen/interface/physdev.h >>> @@ -263,6 +263,8 @@ struct physdev_pci_device { >>> uint8_t devfn; >>> }; >>> >>> +#define PHYSDEVOP_pci_device_state_reset 32 >>> + >>> #define PHYSDEVOP_DBGP_RESET_PREPARE 1 >>> #define PHYSDEVOP_DBGP_RESET_DONE 2 >>> >>> diff --git a/include/xen/pci.h b/include/xen/pci.h >>> index b8337cf85fd1..b2e2e856efd6 100644 >>> --- a/include/xen/pci.h >>> +++ b/include/xen/pci.h >>> @@ -4,10 +4,16 @@ >>> #define __XEN_PCI_H__ >>> >>> #if defined(CONFIG_XEN_DOM0) >>> +int xen_reset_device_state(const struct pci_dev *dev); >>> int xen_find_device_domain_owner(struct pci_dev *dev); >>> int xen_register_device_domain_owner(struct pci_dev *dev, uint16_t domain); >>> int xen_unregister_device_domain_owner(struct pci_dev *dev); >>> #else >>> +static inline int xen_reset_device_state(const struct pci_dev *dev) >>> +{ >>> + return -1; >>> +} >>> + >>> static inline int xen_find_device_domain_owner(struct pci_dev *dev) >>> { >>> return -1; >>> -- >>> 2.34.1 >>> >
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