On Fri, Nov 12, 2010 at 06:13:48PM +0800, Sheng Yang wrote: > On Friday 12 November 2010 17:53:13 Michael S. Tsirkin wrote: > > On Thu, Nov 11, 2010 at 03:46:59PM +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> > > > --- > > > > > > arch/x86/kvm/x86.c | 1 + > > > include/linux/kvm.h | 32 +++++ > > > include/linux/kvm_host.h | 5 + > > > virt/kvm/assigned-dev.c | 316 > > > +++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, > 353 > > > insertions(+), 1 deletions(-) > > > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > > index f3f86b2..847f1e1 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_MSIX_MASK: > > > r = 1; > > > break; > > > > > > case KVM_CAP_COALESCED_MMIO: > > > diff --git a/include/linux/kvm.h b/include/linux/kvm.h > > > index 919ae53..32cd244 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_MSIX_MASK 59 > > > +#endif > > > > > > #ifdef KVM_CAP_IRQ_ROUTING > > > > > > @@ -671,6 +674,9 @@ 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) > > > > > > +/* Available with KVM_CAP_MSIX_MASK */ > > > +#define KVM_GET_MSIX_ENTRY _IOWR(KVMIO, 0x7d, struct > > > kvm_msix_entry) +#define KVM_UPDATE_MSIX_MMIO _IOW(KVMIO, 0x7e, > > > struct kvm_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) > > > > > > @@ -794,4 +800,30 @@ struct kvm_assigned_msix_entry { > > > > > > __u16 padding[3]; > > > > > > }; > > > > > > +#define KVM_MSIX_TYPE_ASSIGNED_DEV 1 > > > + > > > +#define KVM_MSIX_FLAG_MASKBIT (1 << 0) > > > +#define KVM_MSIX_FLAG_QUERY_MASKBIT (1 << 0) > > > + > > > +struct kvm_msix_entry { > > > + __u32 id; > > > + __u32 type; > > > + __u32 entry; /* The index of entry in the MSI-X table */ > > > + __u32 flags; > > > + __u32 query_flags; > > > + __u32 reserved[5]; > > > +}; > > > + > > > +#define KVM_MSIX_MMIO_FLAG_REGISTER (1 << 0) > > > +#define KVM_MSIX_MMIO_FLAG_UNREGISTER (1 << 1) > > > + > > > +struct kvm_msix_mmio { > > > + __u32 id; > > > + __u32 type; > > > + __u64 base_addr; > > > + __u32 max_entries_nr; > > > + __u32 flags; > > > + __u32 reserved[6]; > > > +}; > > > + > > > > > > #endif /* __LINUX_KVM_H */ > > > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > > index 4b31539..9d49074 100644 > > > --- a/include/linux/kvm_host.h > > > +++ b/include/linux/kvm_host.h > > > @@ -445,6 +445,7 @@ struct kvm_guest_msix_entry { > > > > > > }; > > > > > > #define KVM_ASSIGNED_ENABLED_IOMMU (1 << 0) > > > > > > +#define KVM_ASSIGNED_ENABLED_MSIX_MMIO (1 << 1) > > > > > > struct kvm_assigned_dev_kernel { > > > > > > struct kvm_irq_ack_notifier ack_notifier; > > > struct work_struct interrupt_work; > > > > > > @@ -465,6 +466,10 @@ 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; > > > + int msix_max_entries_nr; > > > > > > }; > > > > > > struct kvm_irq_mask_notifier { > > > > > > diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c > > > index 5c6b96d..3010d7d 100644 > > > --- a/virt/kvm/assigned-dev.c > > > +++ b/virt/kvm/assigned-dev.c > > > @@ -226,12 +226,27 @@ static void kvm_free_assigned_irq(struct kvm *kvm, > > > > > > kvm_deassign_irq(kvm, assigned_dev, assigned_dev->irq_requested_type); > > > > > > } > > > > > > +static void unregister_msix_mmio(struct kvm *kvm, > > > + struct kvm_assigned_dev_kernel *adev) > > > +{ > > > + if (adev->flags & KVM_ASSIGNED_ENABLED_MSIX_MMIO) { > > > + mutex_lock(&kvm->slots_lock); > > > + kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, > > > + &adev->msix_mmio_dev); > > > + mutex_unlock(&kvm->slots_lock); > > > + adev->flags &= ~KVM_ASSIGNED_ENABLED_MSIX_MMIO; > > > + } > > > +} > > > + > > > > > > static void kvm_free_assigned_device(struct kvm *kvm, > > > > > > struct kvm_assigned_dev_kernel > > > *assigned_dev) > > > > > > { > > > > > > kvm_free_assigned_irq(kvm, assigned_dev); > > > > > > +#ifdef __KVM_HAVE_MSIX > > > + unregister_msix_mmio(kvm, assigned_dev); > > > +#endif > > > > > > pci_reset_function(assigned_dev->dev); > > > > > > pci_release_regions(assigned_dev->dev); > > > > > > @@ -504,7 +519,7 @@ 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; > > > > > > @@ -564,6 +579,10 @@ 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_ASSIGNED_ENABLED_IOMMU) { > > > > > > if (!kvm->arch.iommu_domain) { > > > > > > r = kvm_iommu_map_guest(kvm); > > > > > > @@ -667,6 +686,43 @@ 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) > > > > > > { > > > > > > @@ -701,6 +757,233 @@ msix_entry_out: > > > return r; > > > > > > } > > > > > > + > > > +static int kvm_vm_ioctl_get_msix_entry(struct kvm *kvm, > > > + struct kvm_msix_entry *entry) > > > +{ > > > + int r = 0; > > > + struct kvm_assigned_dev_kernel *adev; > > > + > > > + if (entry->type != KVM_MSIX_TYPE_ASSIGNED_DEV) > > > + return -EINVAL; > > > + > > > + if (!entry->query_flags) > > > + return -EINVAL; > > > + > > > + mutex_lock(&kvm->lock); > > > + > > > + adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, > > > + entry->id); > > > + > > > + if (!adev) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + > > > + if (entry->entry >= adev->msix_max_entries_nr) { > > > + r = -ENOSPC; > > > + goto out; > > > + } > > > + > > > + if (entry->query_flags & KVM_MSIX_FLAG_QUERY_MASKBIT) { > > > + if (test_bit(entry->entry, adev->msix_mask_bitmap)) > > > + entry->flags |= KVM_MSIX_FLAG_MASKBIT; > > > + else > > > + entry->flags &= ~KVM_MSIX_FLAG_MASKBIT; > > > + } > > > + > > > +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); > > > > I thought we wanted to use a separate flag for this? > > O, flag added, but forgot to update this one. > > > > > + start = adev->msix_mmio_base; > > > + end = adev->msix_mmio_base + PCI_MSIX_ENTRY_SIZE * > > > + adev->msix_max_entries_nr; > > > + if (addr >= start && addr + len <= end) > > > + return true; > > > + > > > + return false; > > > +} > > > + > > > +static int msix_get_enabled_idx(struct kvm_assigned_dev_kernel *adev, > > > + gpa_t addr, int len) > > > +{ > > > + int i, index = (addr - adev->msix_mmio_base) / PCI_MSIX_ENTRY_SIZE; > > > + > > > + for (i = 0; i < adev->entries_nr; i++) > > > + if (adev->guest_msix_entries[i].entry == index) > > > + return i; > > > + > > > + return -EINVAL; > > > +} > > > + > > > > Hmm, we still have a linear scan on each write. Is the point to detect > > which entries need to be handled in kernel? Maybe another bitmap for > > this? Or just handle whole entry write in kernel as well, then we won't > > need this at all. > > Still dont' like handling the whole entry writing. In fact here we have two > questions: > 1. If the entry already enabled > 2. If it is, then what's it sequence number. > > Bitmap can solve question 1, but we still need O(n) scan for the second. So I > think leave it like this should be fine. The spec quoted above implies we must handle all entry writes: a single write can update mask and data. > > > +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; > > > + 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) { > > > + 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); > > > + memcpy(val, &entry[addr % PCI_MSIX_ENTRY_SIZE / sizeof *entry], len); > > > > It seems weird to pass writes to userspace but do reads > > in kernel. > > Either we should support entry read and write or neither. > > Entry read is for speed up, because kernel would write to the mask bit then try to > read from it for flushing. Don't think reading matter much here, as long as > userspace still own routing table. > > > > + > > > +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; > > > > Move this to after you did length and alignment checks, > > it might not be safe here. > > > > > + > > > + mutex_lock(&adev->kvm->lock); > > > + if (!msix_mmio_in_range(adev, addr, len)) { > > > + r = -EOPNOTSUPP; > > > + goto out; > > > + } > > > + if ((addr & 0x3) || len != 4) > > > > The lenght could be 8: > > > > For all accesses to MSI-X Table and MSI-X PBA fields, software must use > > aligned full DWORD or aligned full QWORD transactions; otherwise, the > > result is undefined. > > > > and > > > > Software is permitted to fill in MSI-X Table entry DWORD fields > > individually with DWORD writes, or software in certain cases is permitted > > to fill in appropriate pairs of DWORDs with a single QWORD write. > > Specifically, software is always permitted to fill in the Message Address > > and Message Upper Address fields with a single QWORD write. If a given > > entry is currently masked (via its Mask bit or the Function Mask bit), > > software is permitted to fill in the Message Data and Vector Control > > fields with a single QWORD write, taking advantage of the fact the Message > > Data field is guaranteed to become visible to hardware no later than the > > Vector Control field. However, if software wishes to mask a currently > > unmasked entry (without setting the Function Mask bit), software must set > > the entryâs Mask bit using a DWORD write to the Vector Control field, > > since performing a QWORD write to the Message Data and Vector Control > > fields might result in the Message Data field being modified before the > > Mask bit in the Vector Control field becomes set. > > Haven't seen any device use QWORD accessing. Also QEmu can't handle QWORD MMIO as > well. So I guess we can leave it later. > > > > + goto out; > > > > Why don't we pass to userspace on error? > > Will make it easy to debug ... > > OK, at least we can know if guest want to access it using 8 bits. > > > > > + > > > + 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); > > > + /* It's possible that we need re-enable MSI-X, so go > > > + * back to userspace */ > > > + } > > > + /* 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; > > > > So if the write touches any other bit, we ignore mask bit write > > completely? Don't even pass to userspace? why? > > Because other bits are reserved. The writing behavior is illegal. Spec said result > is undefined. > > -- > regards > Yang, Sheng > > > > > > + 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_update_msix_mmio(struct kvm *kvm, > > > + struct kvm_msix_mmio *msix_mmio) > > > +{ > > > + int r = 0; > > > + struct kvm_assigned_dev_kernel *adev; > > > + > > > + if (msix_mmio->type != KVM_MSIX_TYPE_ASSIGNED_DEV) > > > + return -EINVAL; > > > + > > > + if (!msix_mmio->flags) > > > + return -EINVAL; > > > + > > > + mutex_lock(&kvm->lock); > > > + adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, > > > + msix_mmio->id); > > > + if (!adev) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + if (msix_mmio->base_addr == 0) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + if (msix_mmio->max_entries_nr == 0 || > > > + msix_mmio->max_entries_nr > KVM_MAX_MSIX_PER_DEV) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + > > > + if ((msix_mmio->flags & KVM_MSIX_MMIO_FLAG_REGISTER) && > > > + (msix_mmio->flags & KVM_MSIX_MMIO_FLAG_UNREGISTER)) { > > > + r = -EINVAL; > > > + goto out; > > > + } > > > + > > > + if (msix_mmio->flags & KVM_MSIX_MMIO_FLAG_REGISTER) { > > > + if (!(adev->flags & KVM_ASSIGNED_ENABLED_MSIX_MMIO)) { > > > + mutex_lock(&kvm->slots_lock); > > > + 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) > > > + adev->flags |= KVM_ASSIGNED_ENABLED_MSIX_MMIO; > > > + mutex_unlock(&kvm->slots_lock); > > > + } > > > + if (!r) { > > > + adev->msix_mmio_base = msix_mmio->base_addr; > > > + adev->msix_max_entries_nr = msix_mmio->max_entries_nr; > > > + } > > > + } else if (msix_mmio->flags & KVM_MSIX_MMIO_FLAG_UNREGISTER) > > > + unregister_msix_mmio(kvm, adev); > > > +out: > > > + mutex_unlock(&kvm->lock); > > > + > > > + return r; > > > +} > > > > > > #endif > > > > > > long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl, > > > > > > @@ -813,6 +1096,37 @@ long kvm_vm_ioctl_assigned_device(struct kvm *kvm, > > > unsigned ioctl, > > > > > > goto out; > > > > > > break; > > > > > > } > > > > > > + case KVM_GET_MSIX_ENTRY: { > > > + struct kvm_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_UPDATE_MSIX_MMIO: { > > > + struct kvm_msix_mmio msix_mmio; > > > + > > > + r = -EFAULT; > > > + if (copy_from_user(&msix_mmio, argp, sizeof(msix_mmio))) > > > + goto out; > > > + > > > + r = -EINVAL; > > > + if (find_first_bit((unsigned long *)msix_mmio.reserved, > > > + sizeof(msix_mmio.reserved)) < sizeof(msix_mmio.reserved)) > > > + goto out; > > > + > > > + r = kvm_vm_ioctl_update_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