From: David Woodhouse <dwmw@amazon.co.uk>

Date: Wed, 7 Oct 2020 13:20:44 +0100

Subject: [PATCH 3/5] x86/ioapic: Handle Extended Destination ID field in RTE

Patch-mainline: Never, upstream uses different implementation

References: bsc#1181001, jsc#ECO-3191

The IOAPIC Redirection Table Entries contain an 8-bit Extended

Destination ID field which maps to bits 11-4 of the MSI address.

The lowest bit is used to indicate remappable format, when interrupt

remapping is in use. A hypervisor can use the other 7 bits to permit

guests to address up to 15 bits of APIC IDs, thus allowing 32768 vCPUs

before having to expose a vIOMMU and interrupt remapping to the guest.

No behavioural change in this patch, since nothing yet permits APIC IDs

above 255 to be used with the non-IR IOAPIC domain. Except for the case

where IR is enabled but there are IOAPICs which aren't in the scope of

any IOMMU, which is totally hosed anyway and needs fixing independently

of this change.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

Acked-by: Joerg Roedel <jroedel@suse.de>

---

 arch/x86/include/asm/io_apic.h |    3 ++-

 arch/x86/kernel/apic/io_apic.c |   19 +++++++++++++------

 2 files changed, 15 insertions(+), 7 deletions(-)

--- a/arch/x86/include/asm/io_apic.h

+++ b/arch/x86/include/asm/io_apic.h

@@ -77,7 +77,8 @@ struct IO_APIC_route_entry {

 		mask		:  1,	/* 0: enabled, 1: disabled */

 		__reserved_2	: 15;

-	__u32	__reserved_3	: 24,

+	__u32	__reserved_3	: 17,

+		ext_dest	:  7,

 		dest		:  8;

 } __attribute__ ((packed));

--- a/arch/x86/kernel/apic/io_apic.c

+++ b/arch/x86/kernel/apic/io_apic.c

@@ -1268,10 +1268,10 @@ static void io_apic_print_entries(unsign

 			       buf, (ir_entry->index << 15) | ir_entry->index,

 			       ir_entry->zero);

 		else

-			printk(KERN_DEBUG "%s, %s, D(%02X), M(%1d)\n",

+			printk(KERN_DEBUG "%s, %s, D(%02X%02X), M(%1d)\n",

 			       buf,

 			       entry.dest_mode == IOAPIC_DEST_MODE_LOGICAL ?

-			       "logical " : "physical",

+			       "logical " : "physical", entry.ext_dest,

 			       entry.dest, entry.delivery_mode);

 	}

 }

@@ -1439,6 +1439,7 @@ void native_disable_io_apic(void)

 	 */

 	if (ioapic_i8259.pin != -1) {

 		struct IO_APIC_route_entry entry;

+		u32 apic_id = read_apic_id();

 		memset(&entry, 0, sizeof(entry));

 		entry.mask		= IOAPIC_UNMASKED;

@@ -1446,7 +1447,8 @@ void native_disable_io_apic(void)

 		entry.polarity		= IOAPIC_POL_HIGH;

 		entry.dest_mode		= IOAPIC_DEST_MODE_PHYSICAL;

 		entry.delivery_mode	= dest_ExtINT;

-		entry.dest		= read_apic_id();

+		entry.dest		= apic_id & 0xff;

+		entry.ext_dest		= apic_id >> 8;

 		/*

 		 * Add it to the IO-APIC irq-routing table:

@@ -1861,7 +1863,8 @@ static int ioapic_set_affinity(struct ir

 	raw_spin_lock_irqsave(&ioapic_lock, flags);

 	if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {

 		cfg = irqd_cfg(irq_data);

-		data->entry.dest = cfg->dest_apicid;

+		data->entry.dest = cfg->dest_apicid & 0xff;

+		data->entry.ext_dest = cfg->dest_apicid >> 8;

 		data->entry.vector = cfg->vector;

 		for_each_irq_pin(entry, data->irq_2_pin)

 			__ioapic_write_entry(entry->apic, entry->pin,

@@ -1969,6 +1972,7 @@ static inline void __init unlock_ExtINT_

 	int apic, pin, i;

 	struct IO_APIC_route_entry entry0, entry1;

 	unsigned char save_control, save_freq_select;

+	u32 apic_id;

 	pin  = find_isa_irq_pin(8, mp_INT);

 	if (pin == -1) {

@@ -1984,11 +1988,13 @@ static inline void __init unlock_ExtINT_

 	entry0 = ioapic_read_entry(apic, pin);

 	clear_IO_APIC_pin(apic, pin);

+	apic_id = hard_smp_processor_id();

 	memset(&entry1, 0, sizeof(entry1));

 	entry1.dest_mode = IOAPIC_DEST_MODE_PHYSICAL;

 	entry1.mask = IOAPIC_UNMASKED;

-	entry1.dest = hard_smp_processor_id();

+	entry1.dest = apic_id & 0xff;

+	entry1.ext_dest = apic_id >> 8;

 	entry1.delivery_mode = dest_ExtINT;

 	entry1.polarity = entry0.polarity;

 	entry1.trigger = IOAPIC_EDGE;

@@ -2896,7 +2902,8 @@ static void mp_setup_entry(struct irq_cf

 	memset(entry, 0, sizeof(*entry));

 	entry->delivery_mode = apic->irq_delivery_mode;

 	entry->dest_mode     = apic->irq_dest_mode;

-	entry->dest	     = cfg->dest_apicid;

+	entry->dest	     = cfg->dest_apicid & 0xff;

+	entry->ext_dest	     = cfg->dest_apicid >> 8;

 	entry->vector	     = cfg->vector;

 	entry->trigger	     = data->trigger;

 	entry->polarity	     = data->polarity;