ed8a2f4dde
On KVM GSI routing table updates, specially those where they have vIOMMUs
with interrupt remapping enabled (to boot >255vcpus setups without relying
on KVM_FEATURE_MSI_EXT_DEST_ID), a VMM may update the backing VF MSIs
with a new VCPU affinity.
On AMD with AVIC enabled, the new vcpu affinity info is updated via:
avic_pi_update_irte()
irq_set_vcpu_affinity()
amd_ir_set_vcpu_affinity()
amd_iommu_{de}activate_guest_mode()
Where the IRTE[GATag] is updated with the new vcpu affinity. The GATag
contains VM ID and VCPU ID, and is used by IOMMU hardware to signal KVM
(via GALog) when interrupt cannot be delivered due to vCPU is in
blocking state.
The issue is that amd_iommu_activate_guest_mode() will essentially
only change IRTE fields on transitions from non-guest-mode to guest-mode
and otherwise returns *with no changes to IRTE* on already configured
guest-mode interrupts. To the guest this means that the VF interrupts
remain affined to the first vCPU they were first configured, and guest
will be unable to issue VF interrupts and receive messages like this
from spurious interrupts (e.g. from waking the wrong vCPU in GALog):
[ 167.759472] __common_interrupt: 3.34 No irq handler for vector
[ 230.680927] mlx5_core 0000:00:02.0: mlx5_cmd_eq_recover:247:(pid
3122): Recovered 1 EQEs on cmd_eq
[ 230.681799] mlx5_core 0000:00:02.0:
wait_func_handle_exec_timeout:1113:(pid 3122): cmd[0]: CREATE_CQ(0x400)
recovered after timeout
[ 230.683266] __common_interrupt: 3.34 No irq handler for vector
Given the fact that amd_ir_set_vcpu_affinity() uses
amd_iommu_activate_guest_mode() underneath it essentially means that VCPU
affinity changes of IRTEs are nops. Fix it by dropping the check for
guest-mode at amd_iommu_activate_guest_mode(). Same thing is applicable to
amd_iommu_deactivate_guest_mode() although, even if the IRTE doesn't change
underlying DestID on the host, the VFIO IRQ handler will still be able to
poke at the right guest-vCPU.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.