The struct hyperv_ir_domain_ops is not modified and can be made const to
allow the compiler to put it in read-only memory.
Before:
text data bss dec hex filename
2916 1180 1120 5216 1460 drivers/iommu/hyperv-iommu.o
After:
text data bss dec hex filename
3044 1052 1120 5216 1460 drivers/iommu/hyperv-iommu.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20200525214958.30015-2-rikard.falkeborn@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
On the bare metal, enabling X2APIC mode requires interrupt remapping
function which helps to deliver irq to cpu with 32-bit APIC ID.
Hyper-V doesn't provide interrupt remapping function so far and Hyper-V
MSI protocol already supports to deliver interrupt to the CPU whose
virtual processor index is more than 255. IO-APIC interrupt still has
8-bit APIC ID limitation.
This patch is to add Hyper-V stub IOMMU driver in order to enable
X2APIC mode successfully in Hyper-V Linux guest. The driver returns X2APIC
interrupt remapping capability when X2APIC mode is available. Otherwise,
it creates a Hyper-V irq domain to limit IO-APIC interrupts' affinity
and make sure cpus assigned with IO-APIC interrupt have 8-bit APIC ID.
Define 24 IO-APIC remapping entries because Hyper-V only expose one
single IO-APIC and one IO-APIC has 24 pins according IO-APIC spec(
https://pdos.csail.mit.edu/6.828/2016/readings/ia32/ioapic.pdf).
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
