During interrupt affinity change, it is possible to have interrupts delivered
to the old CPU after the affinity has changed to the new one. To prevent lost
interrupts, local APIC IRR is checked on the old CPU. Similar checks must be
done for posted MSIs given the same reason.
Consider the following scenario:
Device system agent iommu memory CPU/LAPIC
1 FEEX_XXXX
2 Interrupt request
3 Fetch IRTE ->
4 ->Atomic Swap PID.PIR(vec)
Push to Global Observable(GO)
5 if (ON*)
done;*
else
6 send a notification ->
* ON: outstanding notification, 1 will suppress new notifications
If the affinity change happens between 3 and 5 in the IOMMU, the old CPU's
posted interrupt request (PIR) could have the pending bit set for the
vector being moved.
Add a helper function to check individual vector status. Then use the
helper to check for pending interrupts on the source CPU's PID.
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-11-jacob.jun.pan@linux.intel.com
To support posted MSIs, create a posted interrupt descriptor (PID) for each
host CPU. Later on, when setting up interrupt affinity, the IOMMU's
interrupt remapping table entry (IRTE) will point to the physical address
of the matching CPU's PID.
Each PID is initialized with the owner CPU's physical APICID as the
destination.
Originally-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-7-jacob.jun.pan@linux.intel.com
Make the PIR field into u64 such that atomic xchg64 can be used without
ugly casting.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240423174114.526704-3-jacob.jun.pan@linux.intel.com
To prepare native usage of posted interrupts, move the PID declarations out
of VMX code such that they can be shared.
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20240423174114.526704-2-jacob.jun.pan@linux.intel.com
