Virtio devices can now opt-in to use an IOMMU, by setting the use_iommu
field. None of this will work in the current state, since virtio devices
still access memory linearly. A subsequent patch implements sg accesses.
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
---
include/kvm/virtio-mmio.h | 1 +
include/kvm/virtio-pci.h | 1 +
include/kvm/virtio.h | 13 ++++++++++++
virtio/core.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++
virtio/mmio.c | 27 ++++++++++++++++++++++++
virtio/pci.c | 26 ++++++++++++++++++++++++
6 files changed, 120 insertions(+)
diff --git a/include/kvm/virtio-mmio.h b/include/kvm/virtio-mmio.h
index 835f421b..c25a4fd7 100644
--- a/include/kvm/virtio-mmio.h
+++ b/include/kvm/virtio-mmio.h
@@ -44,6 +44,7 @@ struct virtio_mmio_hdr {
struct virtio_mmio {
u32 addr;
void *dev;
+ struct virtio_device *vdev;
struct kvm *kvm;
u8 irq;
struct virtio_mmio_hdr hdr;
diff --git a/include/kvm/virtio-pci.h b/include/kvm/virtio-pci.h
index b70cadd8..26772f74 100644
--- a/include/kvm/virtio-pci.h
+++ b/include/kvm/virtio-pci.h
@@ -22,6 +22,7 @@ struct virtio_pci {
struct pci_device_header pci_hdr;
struct device_header dev_hdr;
void *dev;
+ struct virtio_device *vdev;
struct kvm *kvm;
u16 port_addr;
diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h
index 24c0c487..9f2ff237 100644
--- a/include/kvm/virtio.h
+++ b/include/kvm/virtio.h
@@ -9,6 +9,7 @@
#include <linux/types.h>
#include <sys/uio.h>
+#include "kvm/iommu.h"
#include "kvm/kvm.h"
#define VIRTIO_IRQ_LOW 0
@@ -137,10 +138,12 @@ enum virtio_trans {
};
struct virtio_device {
+ bool use_iommu;
bool use_vhost;
void *virtio;
struct virtio_ops *ops;
u16 endian;
+ void *iotlb;
};
struct virtio_ops {
@@ -182,4 +185,14 @@ static inline void virtio_init_device_vq(struct kvm *kvm,
vring_init(&vq->vring, nr_descs, p, align);
}
+/*
+ * These are callbacks for IOMMU operations on virtio devices. They are not
+ * operations on the virtio-iommu device. Confusing, I know.
+ */
+const struct iommu_properties *
+virtio__iommu_get_properties(struct device_header *dev);
+
+int virtio__iommu_attach(void *, struct virtio_device *vdev, int flags);
+int virtio__iommu_detach(void *, struct virtio_device *vdev);
+
#endif /* KVM__VIRTIO_H */
diff --git a/virtio/core.c b/virtio/core.c
index d6ac289d..32bd4ebc 100644
--- a/virtio/core.c
+++ b/virtio/core.c
@@ -6,11 +6,16 @@
#include "kvm/guest_compat.h"
#include "kvm/barrier.h"
#include "kvm/virtio.h"
+#include "kvm/virtio-iommu.h"
#include "kvm/virtio-pci.h"
#include "kvm/virtio-mmio.h"
#include "kvm/util.h"
#include "kvm/kvm.h"
+static void *iommu = NULL;
+static struct iommu_properties iommu_props = {
+ .name = "viommu-virtio",
+};
const char* virtio_trans_name(enum virtio_trans trans)
{
@@ -198,6 +203,41 @@ bool virtio_queue__should_signal(struct virt_queue *vq)
return false;
}
+const struct iommu_properties *
+virtio__iommu_get_properties(struct device_header *dev)
+{
+ return &iommu_props;
+}
+
+int virtio__iommu_attach(void *priv, struct virtio_device *vdev, int flags)
+{
+ struct virtio_tlb *iotlb = priv;
+
+ if (!iotlb)
+ return -ENOMEM;
+
+ if (vdev->iotlb) {
+ pr_err("device already attached");
+ return -EINVAL;
+ }
+
+ vdev->iotlb = iotlb;
+
+ return 0;
+}
+
+int virtio__iommu_detach(void *priv, struct virtio_device *vdev)
+{
+ if (vdev->iotlb != priv) {
+ pr_err("wrong iotlb"); /* bug */
+ return -EINVAL;
+ }
+
+ vdev->iotlb = NULL;
+
+ return 0;
+}
+
int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
struct virtio_ops *ops, enum virtio_trans trans,
int device_id, int subsys_id, int class)
@@ -233,6 +273,18 @@ int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
return -1;
};
+ if (!iommu && vdev->use_iommu) {
+ iommu_props.pgsize_mask = ~(PAGE_SIZE - 1);
+ /*
+ * With legacy MMIO, we only have 32-bit to hold the vring PFN.
+ * This limits the IOVA size to (32 + 12) = 44 bits, when using
+ * 4k pages.
+ */
+ iommu_props.input_addr_size = 44;
+ iommu = viommu_register(kvm, &iommu_props);
+ }
+
+
return 0;
}
diff --git a/virtio/mmio.c b/virtio/mmio.c
index 16b44fbb..24a14a71 100644
--- a/virtio/mmio.c
+++ b/virtio/mmio.c
@@ -1,4 +1,5 @@
#include "kvm/devices.h"
+#include "kvm/virtio-iommu.h"
#include "kvm/virtio-mmio.h"
#include "kvm/ioeventfd.h"
#include "kvm/iommu.h"
@@ -286,6 +287,30 @@ void virtio_mmio_assign_irq(struct device_header *dev_hdr)
vmmio->irq = irq__alloc_line();
}
+#define mmio_dev_to_virtio(dev_hdr) \
+ container_of(dev_hdr, struct virtio_mmio, dev_hdr)->vdev
+
+static int virtio_mmio_iommu_attach(void *priv, struct device_header *dev_hdr,
+ int flags)
+{
+ return virtio__iommu_attach(priv, mmio_dev_to_virtio(dev_hdr), flags);
+}
+
+static int virtio_mmio_iommu_detach(void *priv, struct device_header *dev_hdr)
+{
+ return virtio__iommu_detach(priv, mmio_dev_to_virtio(dev_hdr));
+}
+
+static struct iommu_ops virtio_mmio_iommu_ops = {
+ .get_properties = virtio__iommu_get_properties,
+ .alloc_address_space = iommu_alloc_address_space,
+ .free_address_space = iommu_free_address_space,
+ .attach = virtio_mmio_iommu_attach,
+ .detach = virtio_mmio_iommu_detach,
+ .map = iommu_map,
+ .unmap = iommu_unmap,
+};
+
int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
int device_id, int subsys_id, int class)
{
@@ -294,6 +319,7 @@ int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
vmmio->addr = virtio_mmio_get_io_space_block(VIRTIO_MMIO_IO_SIZE);
vmmio->kvm = kvm;
vmmio->dev = dev;
+ vmmio->vdev = vdev;
kvm__register_mmio(kvm, vmmio->addr, VIRTIO_MMIO_IO_SIZE,
false, virtio_mmio_mmio_callback, vdev);
@@ -309,6 +335,7 @@ int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
vmmio->dev_hdr = (struct device_header) {
.bus_type = DEVICE_BUS_MMIO,
.data = generate_virtio_mmio_fdt_node,
+ .iommu_ops = vdev->use_iommu ? &virtio_mmio_iommu_ops : NULL,
};
device__register(&vmmio->dev_hdr);
diff --git a/virtio/pci.c b/virtio/pci.c
index b6ef389e..674d5143 100644
--- a/virtio/pci.c
+++ b/virtio/pci.c
@@ -408,6 +408,30 @@ static void virtio_pci__io_mmio_callback(struct kvm_cpu *vcpu,
kvm__emulate_io(vcpu, port, data, direction, len, 1);
}
+#define pci_dev_to_virtio(dev_hdr) \
+ (container_of(dev_hdr, struct virtio_pci, dev_hdr)->vdev)
+
+static int virtio_pci_iommu_attach(void *priv, struct device_header *dev_hdr,
+ int flags)
+{
+ return virtio__iommu_attach(priv, pci_dev_to_virtio(dev_hdr), flags);
+}
+
+static int virtio_pci_iommu_detach(void *priv, struct device_header *dev_hdr)
+{
+ return virtio__iommu_detach(priv, pci_dev_to_virtio(dev_hdr));
+}
+
+static struct iommu_ops virtio_pci_iommu_ops = {
+ .get_properties = virtio__iommu_get_properties,
+ .alloc_address_space = iommu_alloc_address_space,
+ .free_address_space = iommu_free_address_space,
+ .attach = virtio_pci_iommu_attach,
+ .detach = virtio_pci_iommu_detach,
+ .map = iommu_map,
+ .unmap = iommu_unmap,
+};
+
int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
int device_id, int subsys_id, int class)
{
@@ -416,6 +440,7 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
vpci->kvm = kvm;
vpci->dev = dev;
+ vpci->vdev = vdev;
r = ioport__register(kvm, IOPORT_EMPTY, &virtio_pci__io_ops, IOPORT_SIZE, vdev);
if (r < 0)
@@ -461,6 +486,7 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
vpci->dev_hdr = (struct device_header) {
.bus_type = DEVICE_BUS_PCI,
.data = &vpci->pci_hdr,
+ .iommu_ops = vdev->use_iommu ? &virtio_pci_iommu_ops : NULL,
};
vpci->pci_hdr.msix.cap = PCI_CAP_ID_MSIX;
--
2.12.1
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