[PATCH RFC 05/13] x86/irq: Set up per host CPU posted interrupt descriptors

[Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

To support posted MSIs, create a posted interrupt descriptor (PID) for each
host CPU. Later on, when setting up IRQ CPU affinity, 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.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/hardirq.h     |  3 +++
 arch/x86/include/asm/posted_intr.h |  7 +++++++
 arch/x86/kernel/cpu/common.c       |  3 +++
 arch/x86/kernel/irq.c              | 13 +++++++++++++
 4 files changed, 26 insertions(+)

diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index 66837b8c67f1..72c6a084dba3 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -48,6 +48,9 @@ typedef struct {
 
 DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 
+#ifdef CONFIG_X86_POSTED_MSI
+DECLARE_PER_CPU_ALIGNED(struct pi_desc, posted_interrupt_desc);
+#endif
 #define __ARCH_IRQ_STAT
 
 #define inc_irq_stat(member)	this_cpu_inc(irq_stat.member)
diff --git a/arch/x86/include/asm/posted_intr.h b/arch/x86/include/asm/posted_intr.h
index 9f2fa38fa57b..2cd9ac1af835 100644
--- a/arch/x86/include/asm/posted_intr.h
+++ b/arch/x86/include/asm/posted_intr.h
@@ -94,4 +94,11 @@ static inline bool pi_test_sn(struct pi_desc *pi_desc)
 			(unsigned long *)&pi_desc->control);
 }
 
+#ifdef CONFIG_X86_POSTED_MSI
+extern void intel_posted_msi_init(void);
+
+#else
+static inline void intel_posted_msi_init(void) {};
+
+#endif /* X86_POSTED_MSI */
 #endif /* _X86_POSTED_INTR_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4e5ffc8b0e46..08b2d1560f8b 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -65,6 +65,7 @@
 #include <asm/set_memory.h>
 #include <asm/traps.h>
 #include <asm/sev.h>
+#include <asm/posted_intr.h>
 
 #include "cpu.h"
 
@@ -2266,6 +2267,8 @@ void cpu_init(void)
 		barrier();
 
 		x2apic_setup();
+
+		intel_posted_msi_init();
 	}
 
 	mmgrab(&init_mm);
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 11761c124545..fd4d664d81bb 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -22,6 +22,8 @@
 #include <asm/desc.h>
 #include <asm/traps.h>
 #include <asm/thermal.h>
+#include <asm/posted_intr.h>
+#include <asm/irq_remapping.h>
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/irq_vectors.h>
@@ -334,6 +336,17 @@ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_kvm_posted_intr_nested_ipi)
 }
 #endif
 
+#ifdef CONFIG_X86_POSTED_MSI
+
+/* Posted Interrupt Descriptors for coalesced MSIs to be posted */
+DEFINE_PER_CPU_ALIGNED(struct pi_desc, posted_interrupt_desc);
+
+void intel_posted_msi_init(void)
+{
+	this_cpu_write(posted_interrupt_desc.nv, POSTED_MSI_NOTIFICATION_VECTOR);
+	this_cpu_write(posted_interrupt_desc.ndst, this_cpu_read(x86_cpu_to_apicid));
+}
+#endif /* X86_POSTED_MSI */
 
 #ifdef CONFIG_HOTPLUG_CPU
 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
-- 
2.25.1