In order to check if device's interrupts are enabled, this patch adds
a helper function to the MsixConfig structure so that at any point in
time we can check if an interrupt should be delivered or not.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The vector control offset is at the 4th byte of each MSI-X table entry.
For that reason, it is located at 0xc, and not 0x10 as implemented.
This commit fixes the current MSI-X code, allowing proper reading and
writing of each vector control register in the MSI-X table.
Fixes#156
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The offsets returned by the table_offset() and pba_offset() function
were wrong as they were shifting the value by 3 bits. The MSI-X spec
defines the MSI-X table and PBA offsets as being defined on 3-31 bits,
but this does not mean it has to be shifted. Instead, the address is
still on 32 bits and assumes the LSB bits 0-2 are set to 0.
VFIO was working fine with devices were the MSI-X offset were 0x0, but
the bug was found on a device where the offset was non-null.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit enhances the current msi-x code hosted in the pci crate
in order to be reused by the vfio crate. Specifically, it creates
several useful methods for the MsixCap structure that can simplify
the caller's code.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
As mentioned in the PCI specification, the Function Mask from the
Message Control Register can be set to prevent a device from injecting
MSI-X messages. This supersedes the vector masking as it interacts at
the device level.
Here quoted from the specification:
For MSI and MSI-X, while a vector is masked, the function is prohibited
from sending the associated message, and the function must set the
associated Pending bit whenever the function would otherwise send the
message. When software unmasks a vector whose associated Pending bit is
set, the function must schedule sending the associated message, and
clear the Pending bit as soon as the message has been sent. Note that
clearing the MSI-X Function Mask bit may result in many messages
needing to be sent.
This commit implements the behavior described above by reorganizing
the way the PCI configuration space is being written. It is indeed
important to be able to catch a change in the Message Control
Register without having to implement it for every PciDevice
implementation. Instead, the PciConfiguration has been modified to
take care of handling any update made to this register.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The current MSI-X implementation completely ignores the values found
in the Vector Control register related to a specific vector, and never
updates the Pending Bit Array.
According to the PCI specification, MSI-X vectors can be masked
through the Vector Control register on bit 0. If this bit is set,
the device should not inject any MSI message. When the device
runs into such situation, it must not inject the interrupt, but
instead it must update the bit corresponding to the vector number
in the Pending Bit Array.
Later on, if/when the Vector Control register is updated, and if
the bit 0 is flipped from 0 to 1, the device must look into the PBA
to find out if there was a pending interrupt for this specific
vector. If that's the case, an MSI message is injected and the
bit from the PBA is cleared.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
As mentioned in the PCI specification, MSI-X table supports both
DWORD and QWORD accesses:
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.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In order to support MSI-X, this commit adds to the pci crate a new
module called "msix". This module brings all the necessary pieces
to let any PCI device implement MSI-X support.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
