[PATCH 0/7] Use NMI to nofity vCPUs with lapic-pt


Kaige Fu
 

ACRN hypervisor needs to kick vCPU off VMX non-root mode to do some
operations in hypervisor, such as interrupt/exception injection, EPT
flush etc. For non lapic-pt vCPUs, we can use IPI to do so. But, it
doesn't work for lapic-pt vCPUs as the IPI will be injected to VMs
directly without vmexit.

Consequently, there may be fatal errors triggered. 1). Certain operation may not be
carried out on time which may further lead to fatal errors. Taking the
EPT flush request as an example, once we don't flush the EPT on time and
the guest access the out-of-date EPT, fatal error happens. 2). The IPI
vector will be delivered to VMs directly. If the guest can't handle it
properly, further interrupts might be blocked which will cause the VMs
hang.

The NMI can be used as the notification signal to kick the vCPU off VMX
non-root mode for lapic-pt vCPUs. This patchset does it by enable NMI-exiting
after passthroughing the lapic to vCPU.

TODOs:
- Filter out all NMI sources:
* Write ICR with deliver mode NMI
* Program the MSI data with deliver mode NMI
* Program the LVTs with deliver mode NMI
- Implement the smp_call for lapic-pt VMs to facilitate the debug of lapic-pt VMs.

Kaige Fu (7):
HV: Push NMI vector on to the exception stack
HV: Add helper function send_single_nmi
HV: Use NMI to kick lapic-pt vCPU's thread
HV: ignore the NMI injection request for lapic-pt vCPUs
HV: Use NMI-window exiting to address req missing issue
HV: Use NMI to replace INIT signal for lapic-pt VMs S5
HV: Remove INIT signal notification related code

hypervisor/arch/x86/guest/virq.c | 76 ++++++++++++++++++++--------
hypervisor/arch/x86/guest/vmcs.c | 18 +++++--
hypervisor/arch/x86/guest/vmexit.c | 23 +--------
hypervisor/arch/x86/idt.S | 6 +--
hypervisor/arch/x86/irq.c | 55 ++++++++++++++++----
hypervisor/arch/x86/lapic.c | 9 +---
hypervisor/common/schedule.c | 24 ++++++---
hypervisor/include/arch/x86/irq.h | 1 +
hypervisor/include/arch/x86/lapic.h | 4 +-
hypervisor/include/common/schedule.h | 4 +-
10 files changed, 146 insertions(+), 74 deletions(-)

--
2.20.0

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