From: David Woodhouse <dwmw@xxxxxxxxxxxx>
Bits 63-48 of the I/OAPIC Redirection Table Entry map directly to
bits 19-4 of the address used in the resulting MSI cycle.
Historically, the x86 MSI format only used the top 8 of those 16 bits as
the destination APIC ID, and the "Extended Destination ID" in the lower
8 bits was unused.
With interrupt remapping, the lowest bit of the Extended Destination ID
(bit 48 of RTE, bit 4 of MSI address) is now used to indicate a
remappable format MSI.
A hypervisor can use the other 7 bits of the Extended Destination ID 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.
This enlightenment could theoretically be transparent to the I/OAPIC
code if it were always generating its RTE from an MSI message created by
the parent irqchip. That cleanup will happen separately but doesn't cover
all cases — for the ExtINT hackery and restoring boot mode, RTEs are
still generated locally. So we have to teach the I/OAPIC about the
ext_dest bits anyway.
No behavioural change in this patch, since nothing yet permits APIC IDs
above 255 to be used with the non-IR I/OAPIC domain.
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/include/asm/io_apic.h | 3 ++-
arch/x86/kernel/apic/io_apic.c | 19 +++++++++++++------
2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index a1a26f6d3aa4..5bb3cf4ff2fd 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -78,7 +78,8 @@ struct IO_APIC_route_entry {
mask : 1, /* 0: enabled, 1: disabled */
__reserved_2 : 15;
- __u32 __reserved_3 : 24,
+ __u32 __reserved_3 : 17,
+ virt_ext_dest : 7,
dest : 8;
} __attribute__ ((packed));
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index a33380059db6..54f6a029b1d1 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1239,10 +1239,10 @@ static void io_apic_print_entries(unsigned int apic, unsigned int nr_entries)
buf, (ir_entry->index2 << 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.virt_ext_dest,
entry.dest, entry.delivery_mode);
}
}
@@ -1410,6 +1410,7 @@ void native_restore_boot_irq_mode(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;
@@ -1417,7 +1418,8 @@ void native_restore_boot_irq_mode(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.virt_ext_dest = apic_id >> 8;
/*
* Add it to the IO-APIC irq-routing table:
@@ -1861,7 +1863,8 @@ static void ioapic_configure_entry(struct irq_data *irqd)
* ioapic chip to verify that.
*/
if (irqd->chip == &ioapic_chip) {
- mpd->entry.dest = cfg->dest_apicid;
+ mpd->entry.dest = cfg->dest_apicid & 0xff;
+ mpd->entry.virt_ext_dest = cfg->dest_apicid >> 8;
mpd->entry.vector = cfg->vector;
}
for_each_irq_pin(entry, mpd->irq_2_pin)
@@ -2027,6 +2030,7 @@ static inline void __init unlock_ExtINT_logic(void)
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) {
@@ -2042,11 +2046,13 @@ static inline void __init unlock_ExtINT_logic(void)
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.virt_ext_dest = apic_id >> 8;
entry1.delivery_mode = dest_ExtINT;
entry1.polarity = entry0.polarity;
entry1.trigger = IOAPIC_EDGE;
@@ -2949,7 +2955,8 @@ static void mp_setup_entry(struct irq_cfg *cfg, struct mp_chip_data *data,
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->virt_ext_dest = cfg->dest_apicid >> 8;
entry->vector = cfg->vector;
entry->trigger = data->trigger;
entry->polarity = data->polarity;
--
2.26.2
