x86/Hyper-V: Add AMD Secure AVIC for Hyper-V platform

From: Tianyu Lan <[email protected]>

From: Tianyu Lan <[email protected]>

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 v5:
- Rmove extra line and move hv_enable_coco_interrupt() just after hv_set_msr() in the hv_synic_disable_regs().

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      | 9 +++++++++
 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, 30 insertions(+), 1 deletion(-)

2.25.1