[PATCH v3 0/5] Hyper-V VTL support

Saurabh Sengar
2023-03-20T10:04:37Z

This patch series introduces support for Virtual Trust Level (VTL)
in Hyper-V systems. It provide a foundation for the implementation
of Hyper-V VSM support in the Linux kernel, providing a secure
platform for the development and deployment of applications.

Virtual Secure Mode (VSM) is a critical aspect of the security
infrastructure in Hyper-V systems. It provides a set of hypervisor
capabilities and enlightenments that enable the creation and
management of new security boundaries within operating system
software. The VSM achieves and maintains isolation through Virtual
Trust Levels, which are hierarchical, with higher levels being more
privileged than lower levels. Please refer to this link for further
information: https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/vsm

This patch series adds the initialization of the x86 platform for VTL
systems. This also adds the VTL early bootup code for initializing
and bringing up secondary cpus to targeted VTL context. In VTL, AP
has to start directly in the 64-bit mode, bypassing the usual
16-bit -> 32-bit -> 64-bit mode transition sequence that occurs after
waking up an AP with SIPI whose vector points to the 16-bit AP
startup trampoline code.

Currently only VTL level supprted is '2'. This patch series is tested
extensively on VTL2 systems.

[V3]
- Break in to 5 patches
- hv_init_vp_context_t -> hv_init_vp_context
- HYPERV_VTL -> HYPERV_VTL_MODE
- Modify description of HYPERV_VTL_MODE
- VTL 0 and VTL 2 -> VTL0 and VTL2
- Remove casting for this_cpu_ptr pointer

[V2]
- Remove the code for reserve 1 IRQ.
- boot_cpu_has -> cpu_feature_enabled.
- Improved commit message for 0002 patch.
- Improved Kconfig flag description for HYPERV_VTL.
- Removed hv_result as a wrapper around hv_do_hypercall().
- The value of output[0] copied to a local variable before returning.

Saurabh Sengar (5):
x86/init: Make get/set_rtc_noop() public
x86/hyperv: Add VTL specific structs and hypercalls
x86/hyperv: Make hv_get_nmi_reason public
x86/hyperv: VTL support for Hyper-V
x86/Kconfig: Add HYPERV_VTL_MODE

arch/x86/Kconfig | 24 +++
arch/x86/hyperv/Makefile | 1 +
arch/x86/hyperv/hv_vtl.c | 227 +++++++++++++++++++++++++++++
arch/x86/include/asm/hyperv-tlfs.h | 75 ++++++++++
arch/x86/include/asm/mshyperv.h | 15 ++
arch/x86/include/asm/x86_init.h | 2 +
arch/x86/kernel/cpu/mshyperv.c | 6 +-
arch/x86/kernel/x86_init.c | 4 +-
include/asm-generic/hyperv-tlfs.h | 4 +
9 files changed, 351 insertions(+), 7 deletions(-)
create mode 100644 arch/x86/hyperv/hv_vtl.c

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2.34.1