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path: root/arch/um/drivers/virtio_uml.c
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2020-06-02um: Neaten vu_err macro definitionJoe Perches
Defining a macro with ... and __VA_ARGS__ (without ##) can cause compilation errors if a macro use does not have additional args. Add ## to __VA_ARGS__ in the macro definition. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-03-29um: Implement time-travel=extJohannes Berg
This implements synchronized time-travel mode which - using a special application on a unix socket - lets multiple machines take part in a time-travelling simulation together. The protocol for the unix domain socket is defined in the new file include/uapi/linux/um_timetravel.h. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-03-29um: virtio: Implement VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONSJohannes Berg
Implement in-band notifications that are necessary for running vhost-user devices under externally synchronized time-travel mode (which is in a follow-up patch). This feature makes what usually should be eventfd notifications in-band messages. We'll prefer this feature, under the assumption that only a few (simulation) devices will ever support it, since it's not very efficient. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-11-25um: virtio_uml: Disallow modular buildJohannes Berg
This driver *can* be a module, but then its parameters (socket path) are untrusted data from inside the VM, and that isn't allowed. Allow the code to only be built-in to avoid that. Fixes: 5d38f324993f ("um: drivers: Add virtio vhost-user driver") Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-11-25um: virtio: Keep reading on -EAGAINJohannes Berg
When we get an interrupt from the socket getting readable, and start reading, there's a possibility for a race. This depends on the implementation of the device, but e.g. with qemu's libvhost-user, we can see: device virtio_uml --------------------------------------- write header get interrupt read header read body -> returns -EAGAIN write body The -EAGAIN return is because the socket is non-blocking, and then this leads us to abandon this message. In fact, we've already read the header, so when the get another signal/interrupt for the body, we again read it as though it's a new message header, and also abandon it for the same reason (wrong size etc.) This essentially breaks things, and if that message was one that required a response, it leads to a deadlock as the device is waiting for the response but we'll never reply. Fix this by spinning on -EAGAIN as well when we read the message body. We need to handle -EAGAIN as "no message" while reading the header, since we share an interrupt. Note that this situation is highly unlikely to occur in normal usage, since there will be very few messages and only in the startup phase. With the inband call feature this does tend to happen (eventually) though. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-11-25um: virtio: Remove device on disconnectJohannes Berg
If the connection drops, just remove the device, we don't try to recover from this right now. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15um: virtio: Implement VHOST_USER_PROTOCOL_F_REPLY_ACKJohannes Berg
Implement the VHOST_USER_PROTOCOL_F_REPLY_ACK extension for both slave requests (previous patch) where we have to reply and our own requests where it helps understand if the slave failed. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15um: virtio: Implement VHOST_USER_PROTOCOL_F_SLAVE_REQJohannes Berg
Implement the communication channel for the device to notify us of some events, and notably implement the handling of the config updates needed for the combination of this feature and VHOST_USER_PROTOCOL_F_CONFIG. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15um: drivers: Add virtio vhost-user driverErel Geron
This module allows virtio devices to be used over a vhost-user socket. Signed-off-by: Erel Geron <erelx.geron@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>