[PATCH 5/5] x86/apic: Drop APIC_EILVT_NR_MAX and switch to using apic_eilvt_count

[Naveen N Rao (AMD)]

Switch to using apic_eilvt_count as the maximum EILVT register count.
Since this value is no longer a compile-time constant, update
eilvt_offsets to be dynamically allocated. But do so during init instead
of in reserve_eilvt_offset() since the latter is called with preemption
disabled.

Signed-off-by: Naveen N Rao (AMD) <naveen@xxxxxxxxxx>
Tested-by: Manali Shukla <manali.shukla@xxxxxxx>
---
 arch/x86/include/asm/apicdef.h | 1 -
 arch/x86/kernel/apic/apic.c    | 7 +++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h
index ba7657e75ad1..32a242ae0455 100644
--- a/arch/x86/include/asm/apicdef.h
+++ b/arch/x86/include/asm/apicdef.h
@@ -140,7 +140,6 @@
 #define APIC_IER	0x480
 #define APIC_EILVTn(n)	(0x500 + 0x10 * n)
 #define		APIC_EILVT_NR_AMD_10H	4
-#define		APIC_EILVT_NR_MAX	APIC_EILVT_NR_AMD_10H
 
 #define APIC_BASE (fix_to_virt(FIX_APIC_BASE))
 #define APIC_BASE_MSR		0x800
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 748e09c5b322..c4dfd7e93fe4 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -340,7 +340,7 @@ static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
  * necessarily a BIOS bug.
  */
 
-static atomic_t eilvt_offsets[APIC_EILVT_NR_MAX];
+static atomic_t *eilvt_offsets;
 unsigned int apic_eilvt_count __ro_after_init;
 EXPORT_SYMBOL_FOR_KVM(apic_eilvt_count);
 
@@ -355,7 +355,7 @@ static unsigned int reserve_eilvt_offset(int offset, unsigned int new)
 {
 	unsigned int rsvd, vector;
 
-	if (offset >= APIC_EILVT_NR_MAX)
+	if (!eilvt_offsets || offset >= apic_eilvt_count)
 		return ~0;
 
 	rsvd = atomic_read(&eilvt_offsets[offset]);
@@ -418,6 +418,9 @@ static __init void init_eilvt(void)
 
 	if (!apic_eilvt_count)
 		apic_eilvt_count = APIC_EILVT_NR_AMD_10H;
+
+	if (!eilvt_offsets)
+		eilvt_offsets = kzalloc_objs(atomic_t, apic_eilvt_count);
 }
 
 /*
-- 
2.53.0