The guest can disable or never enable Device-TLB. In these cases,
it can't be used even if enabled in QEMU. So, check Device-TLB state
before registering IOMMU notifier and select unmap flag depending on
that. Also, implement a way to change IOMMU notifier flag if Device-TLB
state is changed.
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
---
hw/virtio/vhost-backend.c | 6 ++++++
hw/virtio/vhost.c | 26 ++++++++++++++++++++++++--
include/hw/virtio/vhost-backend.h | 4 ++++
include/hw/virtio/vhost.h | 1 +
4 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 8e581575c9..30eb71fb83 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -297,6 +297,11 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
}
+static void vhost_kernel_toggle_device_iotlb(struct vhost_dev *dev, int enable)
+{
+ vhost_toggle_device_iotlb(dev, enable);
+}
+
const VhostOps kernel_ops = {
.backend_type = VHOST_BACKEND_TYPE_KERNEL,
.vhost_backend_init = vhost_kernel_init,
@@ -328,6 +333,7 @@ const VhostOps kernel_ops = {
.vhost_vsock_set_running = vhost_kernel_vsock_set_running,
.vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
.vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
+ .vhost_toggle_device_iotlb = vhost_kernel_toggle_device_iotlb,
};
#endif
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index a266396576..1bfcc6d263 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -796,7 +796,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
MEMTXATTRS_UNSPECIFIED);
iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
- IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
+ dev->vdev->device_iotlb_enabled ?
+ IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
+ IOMMU_NOTIFIER_UNMAP,
section->offset_within_region,
int128_get64(end),
iommu_idx);
@@ -804,7 +806,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
iommu->iommu_offset = section->offset_within_address_space -
section->offset_within_region;
iommu->hdev = dev;
- ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
+ ret = memory_region_register_iommu_notifier(section->mr, &iommu->n,
+ dev->vdev->device_iotlb_enabled ? NULL : &error_fatal);
if (ret) {
/*
* Some vIOMMUs do not support dev-iotlb yet. If so, try to use the
@@ -841,6 +844,25 @@ static void vhost_iommu_region_del(MemoryListener *listener,
}
}
+void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable)
+{
+ struct vhost_iommu *iommu;
+ int ret;
+
+ QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
+ memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
+ iommu->n.notifier_flags = enable ?
+ IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
+ ret = memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
+ enable ? NULL : &error_fatal);
+ if (ret) {
+ iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
+ memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
+ &error_fatal);
+ }
+ }
+}
+
static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
unsigned idx, bool enable_log)
diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index ec3fbae58d..f8e9660a96 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -133,6 +133,9 @@ typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev,
typedef void (*vhost_reset_status_op)(struct vhost_dev *dev);
+typedef void (*vhost_toggle_device_iotlb_op)(struct vhost_dev *dev,
+ int enabled);
+
typedef struct VhostOps {
VhostBackendType backend_type;
vhost_backend_init vhost_backend_init;
@@ -181,6 +184,7 @@ typedef struct VhostOps {
vhost_force_iommu_op vhost_force_iommu;
vhost_set_config_call_op vhost_set_config_call;
vhost_reset_status_op vhost_reset_status;
+ vhost_toggle_device_iotlb_op vhost_toggle_device_iotlb;
} VhostOps;
int vhost_backend_update_device_iotlb(struct vhost_dev *dev,
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index a52f273347..b3f585c6cd 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
int vhost_net_set_backend(struct vhost_dev *hdev,
struct vhost_vring_file *file);
+void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable);
int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
--
2.35.1On Mon, May 1, 2023 at 10:02 AM Viktor Prutyanov <viktor@daynix.com> wrote:
>
> The guest can disable or never enable Device-TLB. In these cases,
> it can't be used even if enabled in QEMU. So, check Device-TLB state
> before registering IOMMU notifier and select unmap flag depending on
> that. Also, implement a way to change IOMMU notifier flag if Device-TLB
> state is changed.
>
> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
> Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> ---
> hw/virtio/vhost-backend.c | 6 ++++++
> hw/virtio/vhost.c | 26 ++++++++++++++++++++++++--
> include/hw/virtio/vhost-backend.h | 4 ++++
> include/hw/virtio/vhost.h | 1 +
> 4 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> index 8e581575c9..30eb71fb83 100644
> --- a/hw/virtio/vhost-backend.c
> +++ b/hw/virtio/vhost-backend.c
> @@ -297,6 +297,11 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> }
>
> +static void vhost_kernel_toggle_device_iotlb(struct vhost_dev *dev, int enable)
> +{
> + vhost_toggle_device_iotlb(dev, enable);
> +}
> +
> const VhostOps kernel_ops = {
> .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> .vhost_backend_init = vhost_kernel_init,
> @@ -328,6 +333,7 @@ const VhostOps kernel_ops = {
> .vhost_vsock_set_running = vhost_kernel_vsock_set_running,
> .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> + .vhost_toggle_device_iotlb = vhost_kernel_toggle_device_iotlb,
> };
> #endif
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index a266396576..1bfcc6d263 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -796,7 +796,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
> MEMTXATTRS_UNSPECIFIED);
> iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
> - IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
> + dev->vdev->device_iotlb_enabled ?
> + IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
> + IOMMU_NOTIFIER_UNMAP,
> section->offset_within_region,
> int128_get64(end),
> iommu_idx);
> @@ -804,7 +806,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> iommu->iommu_offset = section->offset_within_address_space -
> section->offset_within_region;
> iommu->hdev = dev;
> - ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
> + ret = memory_region_register_iommu_notifier(section->mr, &iommu->n,
> + dev->vdev->device_iotlb_enabled ? NULL : &error_fatal);
> if (ret) {
> /*
> * Some vIOMMUs do not support dev-iotlb yet. If so, try to use the
> @@ -841,6 +844,25 @@ static void vhost_iommu_region_del(MemoryListener *listener,
> }
> }
>
> +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable)
> +{
> + struct vhost_iommu *iommu;
> + int ret;
> +
> + QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
> + memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
> + iommu->n.notifier_flags = enable ?
> + IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
> + ret = memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> + enable ? NULL : &error_fatal);
> + if (ret) {
> + iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
> + memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> + &error_fatal);
I think it's better to tweak the code to avoid doing IOMMU_NOTIFIER_UNMAP twice.
The rest looks good.
Thanks
> + }
> + }
> +}
> +
> static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
> struct vhost_virtqueue *vq,
> unsigned idx, bool enable_log)
> diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> index ec3fbae58d..f8e9660a96 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -133,6 +133,9 @@ typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev,
>
> typedef void (*vhost_reset_status_op)(struct vhost_dev *dev);
>
> +typedef void (*vhost_toggle_device_iotlb_op)(struct vhost_dev *dev,
> + int enabled);
> +
> typedef struct VhostOps {
> VhostBackendType backend_type;
> vhost_backend_init vhost_backend_init;
> @@ -181,6 +184,7 @@ typedef struct VhostOps {
> vhost_force_iommu_op vhost_force_iommu;
> vhost_set_config_call_op vhost_set_config_call;
> vhost_reset_status_op vhost_reset_status;
> + vhost_toggle_device_iotlb_op vhost_toggle_device_iotlb;
> } VhostOps;
>
> int vhost_backend_update_device_iotlb(struct vhost_dev *dev,
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index a52f273347..b3f585c6cd 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
> int vhost_net_set_backend(struct vhost_dev *hdev,
> struct vhost_vring_file *file);
>
> +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable);
> int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
>
> int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
> --
> 2.35.1
>
On Mon, May 8, 2023 at 1:25 PM Jason Wang <jasowang@redhat.com> wrote:
>
> On Mon, May 1, 2023 at 10:02 AM Viktor Prutyanov <viktor@daynix.com> wrote:
> >
> > The guest can disable or never enable Device-TLB. In these cases,
> > it can't be used even if enabled in QEMU. So, check Device-TLB state
> > before registering IOMMU notifier and select unmap flag depending on
> > that. Also, implement a way to change IOMMU notifier flag if Device-TLB
> > state is changed.
> >
> > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
> > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > ---
> > hw/virtio/vhost-backend.c | 6 ++++++
> > hw/virtio/vhost.c | 26 ++++++++++++++++++++++++--
> > include/hw/virtio/vhost-backend.h | 4 ++++
> > include/hw/virtio/vhost.h | 1 +
> > 4 files changed, 35 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > index 8e581575c9..30eb71fb83 100644
> > --- a/hw/virtio/vhost-backend.c
> > +++ b/hw/virtio/vhost-backend.c
> > @@ -297,6 +297,11 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> > }
> >
> > +static void vhost_kernel_toggle_device_iotlb(struct vhost_dev *dev, int enable)
> > +{
> > + vhost_toggle_device_iotlb(dev, enable);
> > +}
> > +
> > const VhostOps kernel_ops = {
> > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > .vhost_backend_init = vhost_kernel_init,
> > @@ -328,6 +333,7 @@ const VhostOps kernel_ops = {
> > .vhost_vsock_set_running = vhost_kernel_vsock_set_running,
> > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> > + .vhost_toggle_device_iotlb = vhost_kernel_toggle_device_iotlb,
> > };
> > #endif
> >
> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > index a266396576..1bfcc6d263 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -796,7 +796,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> > iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
> > MEMTXATTRS_UNSPECIFIED);
> > iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
> > - IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
> > + dev->vdev->device_iotlb_enabled ?
> > + IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
> > + IOMMU_NOTIFIER_UNMAP,
> > section->offset_within_region,
> > int128_get64(end),
> > iommu_idx);
> > @@ -804,7 +806,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> > iommu->iommu_offset = section->offset_within_address_space -
> > section->offset_within_region;
> > iommu->hdev = dev;
> > - ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
> > + ret = memory_region_register_iommu_notifier(section->mr, &iommu->n,
> > + dev->vdev->device_iotlb_enabled ? NULL : &error_fatal);
> > if (ret) {
> > /*
> > * Some vIOMMUs do not support dev-iotlb yet. If so, try to use the
> > @@ -841,6 +844,25 @@ static void vhost_iommu_region_del(MemoryListener *listener,
> > }
> > }
> >
> > +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable)
> > +{
> > + struct vhost_iommu *iommu;
> > + int ret;
> > +
> > + QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
> > + memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
> > + iommu->n.notifier_flags = enable ?
> > + IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
> > + ret = memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> > + enable ? NULL : &error_fatal);
> > + if (ret) {
> > + iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
> > + memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> > + &error_fatal);
>
> I think it's better to tweak the code to avoid doing IOMMU_NOTIFIER_UNMAP twice.
>
> The rest looks good.
Btw, it might worth to add comment to explain why we need this fallback.
Actually, I'm not sure I understand the logic.
E.g if guest tries to enable ATS it means it knows there's a vIOMMU
that support device IOTLB. If we use UNMAP notifier, we will lose the
device device IOTLB event here?
Thanks
>
> Thanks
>
> > + }
> > + }
> > +}
> > +
> > static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
> > struct vhost_virtqueue *vq,
> > unsigned idx, bool enable_log)
> > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> > index ec3fbae58d..f8e9660a96 100644
> > --- a/include/hw/virtio/vhost-backend.h
> > +++ b/include/hw/virtio/vhost-backend.h
> > @@ -133,6 +133,9 @@ typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev,
> >
> > typedef void (*vhost_reset_status_op)(struct vhost_dev *dev);
> >
> > +typedef void (*vhost_toggle_device_iotlb_op)(struct vhost_dev *dev,
> > + int enabled);
> > +
> > typedef struct VhostOps {
> > VhostBackendType backend_type;
> > vhost_backend_init vhost_backend_init;
> > @@ -181,6 +184,7 @@ typedef struct VhostOps {
> > vhost_force_iommu_op vhost_force_iommu;
> > vhost_set_config_call_op vhost_set_config_call;
> > vhost_reset_status_op vhost_reset_status;
> > + vhost_toggle_device_iotlb_op vhost_toggle_device_iotlb;
> > } VhostOps;
> >
> > int vhost_backend_update_device_iotlb(struct vhost_dev *dev,
> > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> > index a52f273347..b3f585c6cd 100644
> > --- a/include/hw/virtio/vhost.h
> > +++ b/include/hw/virtio/vhost.h
> > @@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
> > int vhost_net_set_backend(struct vhost_dev *hdev,
> > struct vhost_vring_file *file);
> >
> > +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable);
> > int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
> >
> > int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
> > --
> > 2.35.1
> >
On Mon, May 8, 2023 at 8:28 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Mon, May 8, 2023 at 1:25 PM Jason Wang <jasowang@redhat.com> wrote:
> >
> > On Mon, May 1, 2023 at 10:02 AM Viktor Prutyanov <viktor@daynix.com> wrote:
> > >
> > > The guest can disable or never enable Device-TLB. In these cases,
> > > it can't be used even if enabled in QEMU. So, check Device-TLB state
> > > before registering IOMMU notifier and select unmap flag depending on
> > > that. Also, implement a way to change IOMMU notifier flag if Device-TLB
> > > state is changed.
> > >
> > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2001312
> > > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > > ---
> > > hw/virtio/vhost-backend.c | 6 ++++++
> > > hw/virtio/vhost.c | 26 ++++++++++++++++++++++++--
> > > include/hw/virtio/vhost-backend.h | 4 ++++
> > > include/hw/virtio/vhost.h | 1 +
> > > 4 files changed, 35 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > > index 8e581575c9..30eb71fb83 100644
> > > --- a/hw/virtio/vhost-backend.c
> > > +++ b/hw/virtio/vhost-backend.c
> > > @@ -297,6 +297,11 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> > > }
> > >
> > > +static void vhost_kernel_toggle_device_iotlb(struct vhost_dev *dev, int enable)
> > > +{
> > > + vhost_toggle_device_iotlb(dev, enable);
> > > +}
> > > +
> > > const VhostOps kernel_ops = {
> > > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > > .vhost_backend_init = vhost_kernel_init,
> > > @@ -328,6 +333,7 @@ const VhostOps kernel_ops = {
> > > .vhost_vsock_set_running = vhost_kernel_vsock_set_running,
> > > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > > .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> > > + .vhost_toggle_device_iotlb = vhost_kernel_toggle_device_iotlb,
> > > };
> > > #endif
> > >
> > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > > index a266396576..1bfcc6d263 100644
> > > --- a/hw/virtio/vhost.c
> > > +++ b/hw/virtio/vhost.c
> > > @@ -796,7 +796,9 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> > > iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
> > > MEMTXATTRS_UNSPECIFIED);
> > > iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
> > > - IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
> > > + dev->vdev->device_iotlb_enabled ?
> > > + IOMMU_NOTIFIER_DEVIOTLB_UNMAP :
> > > + IOMMU_NOTIFIER_UNMAP,
> > > section->offset_within_region,
> > > int128_get64(end),
> > > iommu_idx);
> > > @@ -804,7 +806,8 @@ static void vhost_iommu_region_add(MemoryListener *listener,
> > > iommu->iommu_offset = section->offset_within_address_space -
> > > section->offset_within_region;
> > > iommu->hdev = dev;
> > > - ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
> > > + ret = memory_region_register_iommu_notifier(section->mr, &iommu->n,
> > > + dev->vdev->device_iotlb_enabled ? NULL : &error_fatal);
> > > if (ret) {
> > > /*
> > > * Some vIOMMUs do not support dev-iotlb yet. If so, try to use the
> > > @@ -841,6 +844,25 @@ static void vhost_iommu_region_del(MemoryListener *listener,
> > > }
> > > }
> > >
> > > +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable)
> > > +{
> > > + struct vhost_iommu *iommu;
> > > + int ret;
> > > +
> > > + QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
> > > + memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n);
> > > + iommu->n.notifier_flags = enable ?
> > > + IOMMU_NOTIFIER_DEVIOTLB_UNMAP : IOMMU_NOTIFIER_UNMAP;
> > > + ret = memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> > > + enable ? NULL : &error_fatal);
> > > + if (ret) {
> > > + iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
> > > + memory_region_register_iommu_notifier(iommu->mr, &iommu->n,
> > > + &error_fatal);
> >
> > I think it's better to tweak the code to avoid doing IOMMU_NOTIFIER_UNMAP twice.
> >
> > The rest looks good.
>
> Btw, it might worth to add comment to explain why we need this fallback.
>
> Actually, I'm not sure I understand the logic.
>
> E.g if guest tries to enable ATS it means it knows there's a vIOMMU
> that support device IOTLB. If we use UNMAP notifier, we will lose the
> device device IOTLB event here?
Yes. So, the fallback is not really needed anymore. It can't help if
the guest is going to use Device-TLB (by enabling ATS) but it isn't
available in emulated IOMMU.
Thanks,
Viktor Prutyanov
>
> Thanks
>
> >
> > Thanks
> >
> > > + }
> > > + }
> > > +}
> > > +
> > > static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
> > > struct vhost_virtqueue *vq,
> > > unsigned idx, bool enable_log)
> > > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> > > index ec3fbae58d..f8e9660a96 100644
> > > --- a/include/hw/virtio/vhost-backend.h
> > > +++ b/include/hw/virtio/vhost-backend.h
> > > @@ -133,6 +133,9 @@ typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev,
> > >
> > > typedef void (*vhost_reset_status_op)(struct vhost_dev *dev);
> > >
> > > +typedef void (*vhost_toggle_device_iotlb_op)(struct vhost_dev *dev,
> > > + int enabled);
> > > +
> > > typedef struct VhostOps {
> > > VhostBackendType backend_type;
> > > vhost_backend_init vhost_backend_init;
> > > @@ -181,6 +184,7 @@ typedef struct VhostOps {
> > > vhost_force_iommu_op vhost_force_iommu;
> > > vhost_set_config_call_op vhost_set_config_call;
> > > vhost_reset_status_op vhost_reset_status;
> > > + vhost_toggle_device_iotlb_op vhost_toggle_device_iotlb;
> > > } VhostOps;
> > >
> > > int vhost_backend_update_device_iotlb(struct vhost_dev *dev,
> > > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> > > index a52f273347..b3f585c6cd 100644
> > > --- a/include/hw/virtio/vhost.h
> > > +++ b/include/hw/virtio/vhost.h
> > > @@ -320,6 +320,7 @@ bool vhost_has_free_slot(void);
> > > int vhost_net_set_backend(struct vhost_dev *hdev,
> > > struct vhost_vring_file *file);
> > >
> > > +void vhost_toggle_device_iotlb(struct vhost_dev *dev, bool enable);
> > > int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write);
> > >
> > > int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev,
> > > --
> > > 2.35.1
> > >
>
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