The Memory Space Enable (MSE) bit from the COMMAND register in the
PCI configuration space controls whether a PCI device responds to memory
space accesses, e.g. read and write cycles to the device MMIO regions
defined by its BARs. The MSE bit is used by the device drivers to ensure
the correctness of BAR reprogramming. A common workflow is, the driver
first clears the MSE bit, then writes new values to the BAR registers,
and finally set the MSE bit to finish the BAR reprogramming.
This patch changes how we handle BAR reprogramming for all PCI
devices (e.g. virtio-pci, vfio, vfio-user, etc.), so that we follow the
same convention, e.g. moving PCI BARs when its MSE bit is set.
Note that some device drivers (such as edk2) only clear and set MSE once
while reprogramming multiple BARs of a single device. To support such
behavior, this patch adds support for multiple pending BAR reprogramming.
See: https://github.com/cloud-hypervisor/cloud-hypervisor/issues/7027#issuecomment-2853642959
Signed-off-by: Bo Chen <bchen@crusoe.ai>
A BAR reprogramming of a PCI device will only happen when the (guest)
kernel write to its PCI config space, e.g. the detection of bar
reprogramming (`detect_bar_repgraomming()`) can be embedded to the PCI
config space write (`write_config_register()`). It simplifies APIs
exposed by the `struct PciConfiguration` and `trait PciDevice`. It also
prepares for easier handling of pending bar reprogramming when the MSE
bit of the COMMAND register is not enabled at the time of changing BAR
registers.
See: https://github.com/cloud-hypervisor/cloud-hypervisor/issues/7027#issuecomment-2853642959
Signed-off-by: Bo Chen <bchen@crusoe.ai>
Historically the Cloud Hypervisor coding style has been to ensure that
all imports are ordered and placed in a single group. Unfortunately
cargo fmt has no support for ensuring that all imports are in a single
group so if whitespace lines were added as part of the import statements
then they would only be odered correctly in the group.
By adopting "group_imports="StdExternalCrate" we can enforce a style
where imports are placed in at most three groups for std, external
crates and the crate itself. Choosing a style enforceable by the tooling
reduces the reviewer burden.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
warning: assigning the result of `Clone::clone()` may be inefficient
--> devices/src/pvpanic.rs:213:9
|
213 | self.bar_regions = bars.clone();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_from()`: `self.bar_regions.clone_from(&bars)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assigning_clones
= note: `#[warn(clippy::assigning_clones)]` on by default
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
There is no need for this struct to be public and since it is used in
this module the #[allow(dead_code)] invocation can be removed.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
Implemetion of BusDevice and PciDevice trait for pvpanic device.
Pvpanic device can be implemented as an ISA device or as a
PCI device, we choose PCI device for now.
Signed-off-by: Yi Wang <foxywang@tencent.com>
Introduce emulation of pvpanic device to allow cloud hypervisor to get
the notify from guest's pvpanic driver when guest kernel crash.
Signed-off-by: Yi Wang <foxywang@tencent.com>
