Merge tag 'riscv-mw1-6.16-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/alexghiti/linux into for-next

riscv patches for 6.16-rc1

* Implement atomic patching support for ftrace which finally allows to
  get rid of stop_machine().
* Support for kexec_file_load() syscall
* Improve module loading time by changing the algorithm that counts the
  number of plt/got entries in a module.
* Zicbop is now used in the kernel to prefetch instructions

[Palmer: There's been two rounds of surgery on this one, so as a result
it's a bit different than the PR.]

* alex-pr: (734 commits)
  riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE
  MAINTAINERS: Update Atish's email address
  riscv: hwprobe: export Zabha extension
  riscv: Make regs_irqs_disabled() more clear
  perf symbols: Ignore mapping symbols on riscv
  RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND
  riscv: module: Optimize PLT/GOT entry counting
  riscv: Add support for PUD THP
  riscv: xchg: Prefetch the destination word for sc.w
  riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
  riscv: Add support for Zicbop
  riscv: Introduce Zicbop instructions
  riscv/kexec_file: Fix comment in purgatory relocator
  riscv: kexec_file: Support loading Image binary file
  riscv: kexec_file: Split the loading of kernel and others
  riscv: Documentation: add a description about dynamic ftrace
  riscv: ftrace: support direct call using call_ops
  riscv: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
  riscv: ftrace: support PREEMPT
  riscv: add a data fence for CMODX in the kernel mode
  ...

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

1 files changed, 15 insertions, 14 deletions

diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
index ea3ca5203919..3bc2a03cceca 100644
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -1287,43 +1287,44 @@ static struct irq_chip intel_ir_chip = {
 };
 
 /*
- * With posted MSIs, all vectors are multiplexed into a single notification
- * vector. Devices MSIs are then dispatched in a demux loop where
- * EOIs can be coalesced as well.
+ * With posted MSIs, the MSI vectors are multiplexed into a single notification
+ * vector, and only the notification vector is sent to the APIC IRR.  Device
+ * MSIs are then dispatched in a demux loop that harvests the MSIs from the
+ * CPU's Posted Interrupt Request bitmap.  I.e. Posted MSIs never get sent to
+ * the APIC IRR, and thus do not need an EOI.  The notification handler instead
+ * performs a single EOI after processing the PIR.
  *
- * "INTEL-IR-POST" IRQ chip does not do EOI on ACK, thus the dummy irq_ack()
- * function. Instead EOI is performed by the posted interrupt notification
- * handler.
+ * Note!  Pending SMP/CPU affinity changes, which are per MSI, must still be
+ * honored, only the APIC EOI is omitted.
  *
  * For the example below, 3 MSIs are coalesced into one CPU notification. Only
- * one apic_eoi() is needed.
+ * one apic_eoi() is needed, but each MSI needs to process pending changes to
+ * its CPU affinity.
  *
  * __sysvec_posted_msi_notification()
  *	irq_enter();
  *		handle_edge_irq()
  *			irq_chip_ack_parent()
- *				dummy(); // No EOI
+ *				irq_move_irq(); // No EOI
  *			handle_irq_event()
  *				driver_handler()
  *		handle_edge_irq()
  *			irq_chip_ack_parent()
- *				dummy(); // No EOI
+ *				irq_move_irq(); // No EOI
  *			handle_irq_event()
  *				driver_handler()
  *		handle_edge_irq()
  *			irq_chip_ack_parent()
- *				dummy(); // No EOI
+ *				irq_move_irq(); // No EOI
  *			handle_irq_event()
  *				driver_handler()
  *	apic_eoi()
  *	irq_exit()
+ *
  */
-
-static void dummy_ack(struct irq_data *d) { }
-
 static struct irq_chip intel_ir_chip_post_msi = {
 	.name			= "INTEL-IR-POST",
-	.irq_ack		= dummy_ack,
+	.irq_ack		= irq_move_irq,
 	.irq_set_affinity	= intel_ir_set_affinity,
 	.irq_compose_msi_msg	= intel_ir_compose_msi_msg,
 	.irq_set_vcpu_affinity	= intel_ir_set_vcpu_affinity,