On Friday 05 November 2010 10:44:19 Sheng Yang wrote: > On Thursday 04 November 2010 18:43:22 Michael S. Tsirkin wrote: > > On Thu, Nov 04, 2010 at 02:15:21PM +0800, Sheng Yang wrote: > > > This patch enable per-vector mask for assigned devices using MSI-X. > > > > > > This patch provided two new APIs: one is for guest to specific device's > > > MSI-X table address in MMIO, the other is for userspace to get > > > information about mask bit. > > > > > > All the mask bit operation are kept in kernel, in order to accelerate. > > > Userspace shouldn't access the device MMIO directly for the > > > information, instead it should uses provided API to do so. > > > > > > Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx> > > > --- > > > > > > Documentation/kvm/api.txt | 46 +++++++ > > > arch/x86/kvm/x86.c | 1 + > > > include/linux/kvm.h | 21 +++- > > > include/linux/kvm_host.h | 3 + > > > virt/kvm/assigned-dev.c | 285 > > > ++++++++++++++++++++++++++++++++++++++++++++- 5 files changed, > > 354 > > > > insertions(+), 2 deletions(-) > > > > > > diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt > > > index b336266..69b993c 100644 > > > --- a/Documentation/kvm/api.txt > > > +++ b/Documentation/kvm/api.txt > > > @@ -1085,6 +1085,52 @@ of 4 instructions that make up a hypercall. > > > > > > If any additional field gets added to this structure later on, a bit > > > for that additional piece of information will be set in the flags > > > bitmap. > > > > > > +4.47 KVM_ASSIGN_REG_MSIX_MMIO > > > + > > > +Capability: KVM_CAP_DEVICE_MSIX_MASK > > > +Architectures: x86 > > > +Type: vm ioctl > > > +Parameters: struct kvm_assigned_msix_mmio (in) > > > +Returns: 0 on success, !0 on error > > > + > > > +struct kvm_assigned_msix_mmio { > > > + /* Assigned device's ID */ > > > + __u32 assigned_dev_id; > > > + /* Must be 0 */ > > > + __u32 flags; > > > + /* MSI-X table MMIO address */ > > > + __u64 base_addr; > > > + /* Must be 0, reserved for future use */ > > > + __u64 reserved; > > > > We also want length I think. > > OK, everybody ask for it... > > > > +}; > > > + > > > +This ioctl would enable in-kernel MSI-X emulation, which would handle > > > MSI-X +mask bit in the kernel. > > > > What happens on repeated calls when it's already enabled? > > How does one disable after it's enabled? > > Suppose this should only be called once. But again would update the MMIO > base. It would be disabled along with device deassignment. We enable it > explicitly because not all devices have MSI-X capability. > > > > + > > > > This is very specialized for assigned devices. I would like an > > interface not tied to assigned devices explicitly > > (even if the implementation at the moment only works > > for assigned devices, I can patch that in later). E.g. vhost-net would > > benefit from such an extension too. Maybe tie this to a special > > GSI and this GSI can be an assigned device or not? > > You're talking about KVM_ASSIGN_GET_MSIX_ENTRY? We can't tie it to GSI, > because we should also cover entries without GSI. The entry number should > be fine for all kinds of devices using MSI-X. > > I am not sure about what PV one would looks like. I use > kvm_assigned_msix_entry just because it can be easily reused. > > > > +4.48 KVM_ASSIGN_GET_MSIX_ENTRY > > > + > > > +Capability: KVM_CAP_DEVICE_MSIX_MASK > > > +Architectures: x86 > > > +Type: vm ioctl > > > +Parameters: struct kvm_assigned_msix_entry (in and out) > > > +Returns: 0 on success, !0 on error > > > + > > > +struct kvm_assigned_msix_entry { > > > + /* Assigned device's ID */ > > > + __u32 assigned_dev_id; > > > + /* Ignored */ > > > + __u32 gsi; > > > + /* The index of entry in the MSI-X table */ > > > + __u16 entry; > > > + /* Querying flags and returning status */ > > > + __u16 flags; > > > + /* Must be 0 */ > > > + __u16 padding[2]; > > > +}; > > > + > > > +This ioctl would allow userspace to get the status of one specific > > > MSI-X +entry. Currently we support mask bit status querying. > > > + > > > > > > 5. The kvm_run structure > > > > > > Application code obtains a pointer to the kvm_run structure by > > > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > > index f3f86b2..8fd5121 100644 > > > --- a/arch/x86/kvm/x86.c > > > +++ b/arch/x86/kvm/x86.c > > > @@ -1926,6 +1926,7 @@ int kvm_dev_ioctl_check_extension(long ext) > > > > > > case KVM_CAP_DEBUGREGS: > > > case KVM_CAP_X86_ROBUST_SINGLESTEP: > > > > > > case KVM_CAP_XSAVE: > > > + case KVM_CAP_DEVICE_MSIX_MASK: > > > r = 1; > > > break; > > > > > > case KVM_CAP_COALESCED_MMIO: > > > diff --git a/include/linux/kvm.h b/include/linux/kvm.h > > > index 919ae53..eafafb1 100644 > > > --- a/include/linux/kvm.h > > > +++ b/include/linux/kvm.h > > > @@ -540,6 +540,9 @@ struct kvm_ppc_pvinfo { > > > > > > #endif > > > #define KVM_CAP_PPC_GET_PVINFO 57 > > > #define KVM_CAP_PPC_IRQ_LEVEL 58 > > > > > > +#ifdef __KVM_HAVE_MSIX > > > +#define KVM_CAP_DEVICE_MSIX_MASK 59 > > > +#endif > > > > We seem to have these HAVE macros all over. > > Avi, what's the idea? Let's drop them? > > Um? This kind of marcos are used here to avoid vendor specific string in > the header file. > > > > #ifdef KVM_CAP_IRQ_ROUTING > > > > > > @@ -671,6 +674,10 @@ struct kvm_clock_data { > > > > > > #define KVM_XEN_HVM_CONFIG _IOW(KVMIO, 0x7a, struct > > > kvm_xen_hvm_config) #define KVM_SET_CLOCK _IOW(KVMIO, > > > 0x7b, struct kvm_clock_data) #define KVM_GET_CLOCK > > > _IOR(KVMIO, 0x7c, struct kvm_clock_data) > > > > > > +#define KVM_ASSIGN_GET_MSIX_ENTRY _IOWR(KVMIO, 0x7d, \ > > > + struct kvm_assigned_msix_entry) > > > +#define KVM_ASSIGN_REG_MSIX_MMIO _IOW(KVMIO, 0x7e, \ > > > + struct kvm_assigned_msix_mmio) > > > > > > /* Available with KVM_CAP_PIT_STATE2 */ > > > #define KVM_GET_PIT2 _IOR(KVMIO, 0x9f, struct > > > kvm_pit_state2) #define KVM_SET_PIT2 _IOW(KVMIO, 0xa0, > > > struct kvm_pit_state2) > > > > > > @@ -787,11 +794,23 @@ struct kvm_assigned_msix_nr { > > > > > > }; > > > > > > #define KVM_MAX_MSIX_PER_DEV 256 > > > > > > + > > > +#define KVM_MSIX_FLAG_MASK (1 << 0) > > > +#define KVM_MSIX_FLAG_QUERY_MASK (1 << 15) > > > + > > > > > > struct kvm_assigned_msix_entry { > > > > > > __u32 assigned_dev_id; > > > __u32 gsi; > > > __u16 entry; /* The index of entry in the MSI-X table */ > > > > > > - __u16 padding[3]; > > > + __u16 flags; > > > + __u16 padding[2]; > > > +}; > > > + > > > +struct kvm_assigned_msix_mmio { > > > + __u32 assigned_dev_id; > > > + __u32 flags; > > > + __u64 base_addr; > > > + __u64 reserved; > > > > > > }; > > > > > > #endif /* __LINUX_KVM_H */ > > > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > > index e2ecbac..5ac4db9 100644 > > > --- a/include/linux/kvm_host.h > > > +++ b/include/linux/kvm_host.h > > > @@ -464,6 +464,9 @@ struct kvm_assigned_dev_kernel { > > > > > > struct pci_dev *dev; > > > struct kvm *kvm; > > > spinlock_t assigned_dev_lock; > > > > > > + DECLARE_BITMAP(msix_mask_bitmap, KVM_MAX_MSIX_PER_DEV); > > > + gpa_t msix_mmio_base; > > > + struct kvm_io_device msix_mmio_dev; > > > > > > }; > > > > > > struct kvm_irq_mask_notifier { > > > > > > diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c > > > index 7c98928..9398c27 100644 > > > --- a/virt/kvm/assigned-dev.c > > > +++ b/virt/kvm/assigned-dev.c > > > @@ -232,6 +232,14 @@ static void kvm_free_assigned_device(struct kvm > > > *kvm, > > > > > > { > > > > > > kvm_free_assigned_irq(kvm, assigned_dev); > > > > > > +#ifdef __KVM_HAVE_MSIX > > > + if (assigned_dev->msix_mmio_base) { > > > + mutex_lock(&kvm->slots_lock); > > > + kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, > > > + &assigned_dev->msix_mmio_dev); > > > + mutex_unlock(&kvm->slots_lock); > > > + } > > > +#endif > > > > > > pci_reset_function(assigned_dev->dev); > > > > > > pci_release_regions(assigned_dev->dev); > > > > > > @@ -504,7 +512,7 @@ out: > > > static int kvm_vm_ioctl_assign_device(struct kvm *kvm, > > > > > > struct kvm_assigned_pci_dev *assigned_dev) > > > > > > { > > > > > > - int r = 0, idx; > > > + int r = 0, idx, i; > > > > > > struct kvm_assigned_dev_kernel *match; > > > struct pci_dev *dev; > > > > > > @@ -563,6 +571,10 @@ static int kvm_vm_ioctl_assign_device(struct kvm > > > *kvm, > > > > > > list_add(&match->list, &kvm->arch.assigned_dev_head); > > > > > > + /* The state after reset of MSI-X table is all masked */ > > > + for (i = 0; i < KVM_MAX_MSIX_PER_DEV; i++) > > > + set_bit(i, match->msix_mask_bitmap); > > > + > > > > > > if (assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU) { > > > > > > if (!kvm->arch.iommu_domain) { > > > > > > r = kvm_iommu_map_guest(kvm); > > > > > > @@ -666,6 +678,43 @@ msix_nr_out: > > > return r; > > > > > > } > > > > > > +static void update_msix_mask(struct kvm_assigned_dev_kernel *adev, > > > + int idx, bool new_mask_flag) > > > +{ > > > + int irq; > > > + bool old_mask_flag, need_flush = false; > > > + > > > + spin_lock_irq(&adev->assigned_dev_lock); > > > + > > > + if (!adev->dev->msix_enabled || > > > + !(adev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX)) > > > + goto out; > > > + > > > + old_mask_flag = test_bit(adev->guest_msix_entries[idx].entry, > > > + adev->msix_mask_bitmap); > > > + if (old_mask_flag == new_mask_flag) > > > + goto out; > > > + > > > + irq = adev->host_msix_entries[idx].vector; > > > + BUG_ON(irq == 0); > > > + > > > + if (new_mask_flag) { > > > + set_bit(adev->guest_msix_entries[idx].entry, > > > + adev->msix_mask_bitmap); > > > + disable_irq_nosync(irq); > > > + need_flush = true; > > > + } else { > > > + clear_bit(adev->guest_msix_entries[idx].entry, > > > + adev->msix_mask_bitmap); > > > + enable_irq(irq); > > > + } > > > +out: > > > + spin_unlock_irq(&adev->assigned_dev_lock); > > > + > > > + if (need_flush) > > > + flush_work(&adev->interrupt_work); > > > +} > > > + > > > > > > static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm, > > > > > > struct kvm_assigned_msix_entry *entry) > > > > > > { > > > > > > @@ -700,6 +749,210 @@ msix_entry_out: > > > return r; > > > > > > } > > > > > > + > > > +static int kvm_vm_ioctl_get_msix_entry(struct kvm *kvm, > > > + struct kvm_assigned_msix_entry *entry) > > > +{ > > > + int r = 0; > > > + struct kvm_assigned_dev_kernel *adev; > > > + > > > + mutex_lock(&kvm->lock); > > > + > > > + adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, > > > + entry->assigned_dev_id); > > > + > > > + if (!adev) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + > > > + if (entry->entry >= KVM_MAX_MSIX_PER_DEV) { > > > + r = -ENOSPC; > > > + goto out; > > > + } > > > + > > > + if (entry->flags & KVM_MSIX_FLAG_QUERY_MASK) { > > > + if (test_bit(entry->entry, adev->msix_mask_bitmap)) > > > + entry->flags |= KVM_MSIX_FLAG_MASK; > > > + else > > > + entry->flags &= ~KVM_MSIX_FLAG_MASK; > > > + } > > > + > > > +out: > > > + mutex_unlock(&kvm->lock); > > > + > > > + return r; > > > +} > > > + > > > +static bool msix_mmio_in_range(struct kvm_assigned_dev_kernel *adev, > > > + gpa_t addr, int len) > > > +{ > > > + gpa_t start, end; > > > + > > > + BUG_ON(adev->msix_mmio_base == 0); > > > > Below I see > > > > adev->msix_mmio_base = msix_mmio->base_addr; > > > > which comes from userspace. BUG_ON is an unfriendly way to > > tell user about a bug in qemu. > > > > Anyway, I don't think we should special-case 0 gpa. > > It's up to the user where to base the table. > > Use a separate flag to signal that table was initialized. > > Base_addr can't be 0 in any case. Only the unimplemented BAR are hardwired > to zero. Also if we get here with base_addr = 0, it is surely a bug. > > > > + start = adev->msix_mmio_base; > > > + end = adev->msix_mmio_base + PCI_MSIX_ENTRY_SIZE * > > > KVM_MAX_MSIX_PER_DEV; > > > > This seems wrong. What if the device has a smaller msix table? > > Can't we simply pass in base and length? > > OK, OK, you would have it... > > > > + if (addr >= start && addr + len <= end) > > > > interesting wrap-around cases come to mind. Likely not a real > > problem but maybe better use addr + len - 1 all over > > to make it robust. > > Quite good point. :) > > > > + return true; > > > + > > > + return false; > > > +} > > > + > > > +static int msix_get_enabled_idx(struct kvm_assigned_dev_kernel *adev, > > > + gpa_t addr, int len) > > > +{ > > > + int i; > > > + gpa_t start, end; > > > + > > > + for (i = 0; i < adev->entries_nr; i++) { > > > + start = adev->msix_mmio_base + > > > + adev->guest_msix_entries[i].entry * PCI_MSIX_ENTRY_SIZE; > > > + end = start + PCI_MSIX_ENTRY_SIZE; > > > + if (addr >= start && addr + len <= end) { > > > + return i; > > > + } > > > + } > > > > That's a scary thing to do on each access. > > Can we build an interface that does not force us > > to scan the whole list each time? > > We can reduced the calculation. But seems it can't be O(1) without > introducing more variables to help. > > > > + > > > + return -EINVAL; > > > +} > > > + > > > +static int msix_mmio_read(struct kvm_io_device *this, gpa_t addr, int > > > len, + void *val) > > > +{ > > > + struct kvm_assigned_dev_kernel *adev = > > > + container_of(this, struct kvm_assigned_dev_kernel, > > > + msix_mmio_dev); > > > + int idx, r = 0; > > > + u32 entry[4]; > > > + struct kvm_kernel_irq_routing_entry e; > > > + > > > + mutex_lock(&adev->kvm->lock); > > > + if (!msix_mmio_in_range(adev, addr, len)) { > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + if ((addr & 0x3) || len != 4) > > > + goto out; > > > + > > > + idx = msix_get_enabled_idx(adev, addr, len); > > > + if (idx < 0) { > > > + idx = (addr - adev->msix_mmio_base) / PCI_MSIX_ENTRY_SIZE; > > > + if ((addr % PCI_MSIX_ENTRY_SIZE) == > > > + PCI_MSIX_ENTRY_VECTOR_CTRL) > > > + *(unsigned long *)val = > > > + test_bit(idx, adev->msix_mask_bitmap) ? > > > + PCI_MSIX_ENTRY_CTRL_MASKBIT : 0; > > > > I suspect this is wrong for big endian platforms: PCI returns > > all values in little endian format. > > Let big endian platform take care of it later... There is only x86 has > __KVM_HAVE_MSIX now. > > > > + else > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + > > > + r = kvm_get_irq_routing_entry(adev->kvm, > > > + adev->guest_msix_entries[idx].vector, &e); > > > + if (r || e.type != KVM_IRQ_ROUTING_MSI) { > > > + printk(KERN_WARNING "KVM: Wrong MSI-X routing entry! " > > > + "idx %d, addr 0x%llx, len %d\n", idx, addr, len); > > > > Can a malicious userspace trigger this intentionally? > > No. > > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + entry[0] = e.msi.address_lo; > > > + entry[1] = e.msi.address_hi; > > > + entry[2] = e.msi.data; > > > + entry[3] = test_bit(adev->guest_msix_entries[idx].entry, > > > + adev->msix_mask_bitmap); > > > > I suspect this is wrong for big endian platforms: PCI returns > > all values in little endian format. > > > > > + memcpy(val, &entry[addr % PCI_MSIX_ENTRY_SIZE / 4 > > > > 4 is sizeof *entry? > > 4 elements. In fact "PCI_MSIX_ENTRY_SIZE / sizeof u32". Well, sizeof *entry is correct in sematic. Would update it. -- regards Yang, Sheng > > > ], len); > > > > > + > > > +out: > > > + mutex_unlock(&adev->kvm->lock); > > > + return r; > > > +} > > > + > > > +static int msix_mmio_write(struct kvm_io_device *this, gpa_t addr, int > > > len, + const void *val) > > > +{ > > > + struct kvm_assigned_dev_kernel *adev = > > > + container_of(this, struct kvm_assigned_dev_kernel, > > > + msix_mmio_dev); > > > + int idx, r = 0; > > > + unsigned long new_val = *(unsigned long *)val; > > > > I suspect this is wrong for big endian platforms: PCI returns > > all values in little endian format. > > > > > + > > > + mutex_lock(&adev->kvm->lock); > > > + if (!msix_mmio_in_range(adev, addr, len)) { > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + if ((addr & 0x3) || len != 4) > > > + goto out; > > > + > > > + idx = msix_get_enabled_idx(adev, addr, len); > > > + if (idx < 0) { > > > + idx = (addr - adev->msix_mmio_base) / PCI_MSIX_ENTRY_SIZE; > > > + if (((addr % PCI_MSIX_ENTRY_SIZE) == > > > + PCI_MSIX_ENTRY_VECTOR_CTRL)) { > > > + if (new_val & ~PCI_MSIX_ENTRY_CTRL_MASKBIT) > > > + goto out; > > > + if (new_val & PCI_MSIX_ENTRY_CTRL_MASKBIT) > > > + set_bit(idx, adev->msix_mask_bitmap); > > > + else > > > + clear_bit(idx, adev->msix_mask_bitmap); > > > + } else > > > + /* Userspace would handle other MMIO writing */ > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + if (addr % PCI_MSIX_ENTRY_SIZE != PCI_MSIX_ENTRY_VECTOR_CTRL) { > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + if (new_val & ~PCI_MSIX_ENTRY_CTRL_MASKBIT) > > > + goto out; > > > + update_msix_mask(adev, idx, !!(new_val & > > > PCI_MSIX_ENTRY_CTRL_MASKBIT)); +out: > > > + mutex_unlock(&adev->kvm->lock); > > > + > > > + return r; > > > +} > > > + > > > +static const struct kvm_io_device_ops msix_mmio_ops = { > > > + .read = msix_mmio_read, > > > + .write = msix_mmio_write, > > > +}; > > > + > > > +static int kvm_vm_ioctl_register_msix_mmio(struct kvm *kvm, > > > + struct kvm_assigned_msix_mmio *msix_mmio) > > > +{ > > > + int r = 0; > > > + struct kvm_assigned_dev_kernel *adev; > > > + > > > + mutex_lock(&kvm->lock); > > > + adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, > > > + msix_mmio->assigned_dev_id); > > > + if (!adev) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + if (msix_mmio->base_addr == 0) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + > > > + mutex_lock(&kvm->slots_lock); > > > + if (adev->msix_mmio_base == 0) { > > > > What does this do? Handles case we are already registered? > > Also ! adev->msix_mmio_base > > We don't need to register again. Just update the address. > > Well, msix_mmio_base is an address. I think ==0 is more properly. > > -- > regards > Yang, Sheng > > > > + kvm_iodevice_init(&adev->msix_mmio_dev, &msix_mmio_ops); > > > + r = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, > > > + &adev->msix_mmio_dev); > > > + if (r) > > > + goto out2; > > > + } > > > + > > > + adev->msix_mmio_base = msix_mmio->base_addr; > > > +out2: > > > + mutex_unlock(&kvm->slots_lock); > > > +out: > > > + mutex_unlock(&kvm->lock); > > > + > > > + return r; > > > +} > > > > > > #endif > > > > > > long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl, > > > > > > @@ -812,6 +1065,36 @@ long kvm_vm_ioctl_assigned_device(struct kvm > > > *kvm, unsigned ioctl, > > > > > > goto out; > > > > > > break; > > > > > > } > > > > > > + case KVM_ASSIGN_GET_MSIX_ENTRY: { > > > + struct kvm_assigned_msix_entry entry; > > > + r = -EFAULT; > > > + if (copy_from_user(&entry, argp, sizeof entry)) > > > + goto out; > > > + r = kvm_vm_ioctl_get_msix_entry(kvm, &entry); > > > + if (r) > > > + goto out; > > > + r = -EFAULT; > > > + if (copy_to_user(argp, &entry, sizeof entry)) > > > + goto out; > > > + r = 0; > > > + break; > > > + } > > > + case KVM_ASSIGN_REG_MSIX_MMIO: { > > > + struct kvm_assigned_msix_mmio msix_mmio; > > > + > > > + r = -EFAULT; > > > + if (copy_from_user(&msix_mmio, argp, sizeof(msix_mmio))) > > > + goto out; > > > + > > > + r = -EINVAL; > > > + if (msix_mmio.flags != 0 || msix_mmio.reserved != 0) > > > + goto out; > > > + > > > + r = kvm_vm_ioctl_register_msix_mmio(kvm, &msix_mmio); > > > + if (r) > > > + goto out; > > > + break; > > > + } > > > > > > #endif > > > > > > } > > > > > > out: -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html