Messages in this thread | | | Subject | Re: [PATCH v4 4/7] vfio: ap: register IOMMU VFIO notifier | From | Pierre Morel <> | Date | Thu, 28 Feb 2019 09:48:39 +0100 |
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On 28/02/2019 09:23, Christian Borntraeger wrote: > On 22.02.2019 16:29, Pierre Morel wrote: >> To be able to use the VFIO interface to facilitate the >> mediated device memory pining/unpining we need to register >> a notifier for IOMMU. > > You might want to add that while we start to pin one guest page for the > interrupt indicator byte in the next patch, this is still ok with ballooning > as this page will never be used by the guest virtio-balloon driver. So the > pinned page will never be freed. And even a broken guest does so, that would > not impact the host as the original page is still in control by vfio. >
Thanks, I ll do.
Regards, Pierre
>> >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_ops.c | 53 ++++++++++++++++++++++++++++++++--- >> drivers/s390/crypto/vfio_ap_private.h | 2 ++ >> 2 files changed, 51 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c >> index 172d6eb..1b5130a 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -748,6 +748,36 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = { >> }; >> >> /** >> + * vfio_ap_mdev_iommu_notifier: IOMMU notifier callback >> + * >> + * @nb: The notifier block >> + * @action: Action to be taken (VFIO_IOMMU_NOTIFY_DMA_UNMAP) >> + * @data: the specific unmap structure for vfio_iommu_type1 >> + * >> + * Unpins the guest IOVA. (The NIB guest address we pinned before). >> + * Return NOTIFY_OK after unpining on a UNMAP request. >> + * otherwise, returns NOTIFY_DONE . >> + */ >> +static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb, >> + unsigned long action, void *data) >> +{ >> + struct ap_matrix_mdev *matrix_mdev; >> + >> + matrix_mdev = container_of(nb, struct ap_matrix_mdev, iommu_notifier); >> + >> + if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) { >> + struct vfio_iommu_type1_dma_unmap *unmap = data; >> + unsigned long g_pfn = unmap->iova >> PAGE_SHIFT; >> + >> + vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn, 1); >> + return NOTIFY_OK; >> + } >> + >> + return NOTIFY_DONE; >> +} >> + >> + >> +/** >> * vfio_ap_mdev_set_kvm >> * >> * @matrix_mdev: a mediated matrix device >> @@ -846,12 +876,25 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) >> >> ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >> &events, &matrix_mdev->group_notifier); >> - if (ret) { >> - module_put(THIS_MODULE); >> - return ret; >> - } >> + if (ret) >> + goto err_group; >> + >> + matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier; >> + events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; >> + >> + ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, >> + &events, &matrix_mdev->iommu_notifier); >> + if (ret) >> + goto err_iommu; >> >> return 0; >> + >> +err_iommu: >> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >> + &matrix_mdev->group_notifier); >> +err_group: >> + module_put(THIS_MODULE); >> + return ret; >> } >> >> static void vfio_ap_mdev_release(struct mdev_device *mdev) >> @@ -864,6 +907,8 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev) >> vfio_ap_mdev_reset_queues(mdev); >> vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >> &matrix_mdev->group_notifier); >> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, >> + &matrix_mdev->iommu_notifier); >> matrix_mdev->kvm = NULL; >> module_put(THIS_MODULE); >> } >> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h >> index 2760178..e535735 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -81,8 +81,10 @@ struct ap_matrix_mdev { >> struct list_head node; >> struct ap_matrix matrix; >> struct notifier_block group_notifier; >> + struct notifier_block iommu_notifier; >> struct kvm *kvm; >> struct list_head qlist; >> + struct mdev_device *mdev; >> }; >> >> extern int vfio_ap_mdev_register(void); >>
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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