vt-d: use 32-bit Destination ID when Interrupt Remapping with EIM is

enabled

When x2APIC and Interrupt Remapping(IR) with EIM are enabled, we
should use 32-bit Destination ID for IOAPIC and MSI.

We implemented the IR support in xen by hooking the functions like
io_apic_write(),io_apic_modify(), write_msi_message(), and as a
result, in the hook functions in intremap.c, we can only see the 8-bit
dest id rather the 32-bit id, so we can't set IR table Entry that
requires a 32-bit dest id.

To solve the issue throughly, we need find every place in io_apic.c
and msi.c that could write ioapic RTE and and device's msi message and
explicitly handle the 32-bit dest id carefully (namely, when genapic
is x2apic, cpu_mask_to_apic could return a 32-bit value); and we have
to change the iommu_ops->{.update_ire_from_apic, .update_ire_from_msi}
interfaces. We may have to write an over-1000-LOC patch for this.

Instead, we could use a workround:
1) for ioapic, in the struct IO_APIC_route_entry, we could use a new
"dest32" to refer to the dest field;
2) for msi, in the struct msi_msg, we could add a new "u32 dest".
And in intremap.c, if x2apic_enabled, we use the new names to refer to
the dest fields.

We can improve this in future.

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/xen/include/asm-x86/msi.h b/xen/include/asm-x86/msi.h
index dc9877b0a2..9df5ccb193 100644
--- a/xen/include/asm-x86/msi.h
+++ b/xen/include/asm-x86/msi.h
@@ -65,6 +65,7 @@ struct msi_msg {
 	u32	address_lo;	/* low 32 bits of msi message address */
 	u32	address_hi;	/* high 32 bits of msi message address */
 	u32	data;		/* 16 bits of msi message data */
+	u32	dest32;		/* used when Interrupt Remapping with EIM is enabled */
 };
 
 struct msi_desc;