[RFC PATCH V5 0/4] x86/Hyper-V: Add AMD Secure AVIC for Hyper-V platform

[Tianyu Lan <ltykernel@gmail.com>]

From: Tianyu Lan <tiala@microsoft.com>

Secure AVIC is a new hardware feature in the AMD64
architecture to allow SEV-SNP guests to prevent the
hypervisor from generating unexpected interrupts to
a vCPU or otherwise violate architectural assumptions
around APIC behavior.

Each vCPU has a guest-allocated APIC backing page of
size 4K, which maintains APIC state for that vCPU.
APIC backing page's ALLOWED_IRR field indicates the
interrupt vectors which the guest allows the hypervisor
to send.

This patchset is to enable the feature for Hyper-V
platform. Patch "Drivers: hv: Allow vmbus message
synic interrupt injected from Hyper-V" is to expose
new fucntion hv_enable_coco_interrupt() and device
driver and arch code may update AVIC backing page
ALLOWED_IRR field to allow Hyper-V inject associated
vector.

This patchset is based on the AMD patchset "AMD: Add
Secure AVIC Guest Support"
https://lkml.org/lkml/2025/6/10/1579

Change since v4:
        - Change the order to call hv_enable_coco_interrupt()
	  in the hv_synic_enable/disable_regs().
	- Update commit title "Drivers/hv:" to "Drivers: hv:"

Change since v3:
        - Disable VMBus Message interrupt via hv_enable_
          coco_interrupt() in the hv_synic_disable_regs().
        - Fix coding style issue and update change log.

Change since v2:
       - Add hv_enable_coco_interrupt() as wrapper
        of apic_update_vector()
       - Re-work change logs

Change since v1:
       - Remove the check of Secure AVIC when set APIC backing page
       - Use apic_update_vector() instead of exposing new interface
       from Secure AVIC driver to update APIC backing page and allow
       associated interrupt to be injected by hypervisor.

Tianyu Lan (4):
  x86/hyperv: Don't use hv apic driver when Secure AVIC is available
  Drivers: hv: Allow vmbus message synic interrupt injected from Hyper-V
  x86/hyperv: Don't use auto-eoi when Secure AVIC is available
  x86/hyperv: Allow Hyper-V to inject STIMER0 interrupts

 arch/x86/hyperv/hv_apic.c      | 8 ++++++++
 arch/x86/hyperv/hv_init.c      | 7 +++++++
 arch/x86/kernel/cpu/mshyperv.c | 2 ++
 drivers/hv/hv.c                | 7 ++++++-
 drivers/hv/hv_common.c         | 5 +++++
 include/asm-generic/mshyperv.h | 1 +
 6 files changed, 29 insertions(+), 1 deletion(-)

-- 
2.25.1