Hi, On Fri, Apr 21, 2023 at 09:45:54AM -0400, Yang Weijiang wrote: > > Tests: > -------------------------------------------------------------------------- > This series passed basic CET user shadow stack test and kernel IBT test in > L1 and L2 guest. It also passed CET KUT test which has been merged there. > > Executed all KUT tests and KVM selftests against this series, all test cases > passes except the vmx test, the failure is due to CR4_CET bit testing in > test_vmxon_bad_cr(). After add CR4_CET bit to skip list, the test passed. > I'll send a patch to fix this issue later. > > > To run user shadow stack test and kernel IBT test in VM, you need an CET > capable platform, e.g., Sapphire Rapids server, and follow below steps to > build host/guest kernel properly: > > 1. Buld host kernel. Patch this series to kernel tree and build kernel > with CET capable gcc version(e.g., >=8.5.0). > > 2. Build guest kernel. Patch CET native series to kernel tree and opt-in > CONFIG_X86_KERNEL_IBT and CONFIG_X86_USER_SHADOW_STACK options. > > 3. Launch a VM with QEMU built with CET enabling patches [2]. > > Check kernel selftest test_shadow_stack_64 output: > [INFO] new_ssp = 7f8c82100ff8, *new_ssp = 7f8c82101001 > [INFO] changing ssp from 7f8c82900ff0 to 7f8c82100ff8 > [INFO] ssp is now 7f8c82101000 > [OK] Shadow stack pivot > [OK] Shadow stack faults > [INFO] Corrupting shadow stack > [INFO] Generated shadow stack violation successfully > [OK] Shadow stack violation test > [INFO] Gup read -> shstk access success > [INFO] Gup write -> shstk access success > [INFO] Violation from normal write > [INFO] Gup read -> write access success > [INFO] Violation from normal write > [INFO] Gup write -> write access success > [INFO] Cow gup write -> write access success > [OK] Shadow gup test > [INFO] Violation from shstk access > [OK] mprotect() test > [SKIP] Userfaultfd unavailable. > [OK] 32 bit test > > Check kernel IBT with dmesg | grep CET: > CET detected: Indirect Branch Tracking enabled > > -------------------------------------------------------------------------- > Changes in v2: > 1. Remove excessive checks on host CET Kconfig options in v1 patchset [3]. > 2. Make CET CPUIDs, MSRs and control flags enabling independent to host CET status. > 3. Introduce supervisor SHSTK support to make the patch set complete. > 4. Refactor patches to accommodate above changes. > 5. Rebase on kvm-x86/next [4]. > > > [1]: linux-next: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/?h=next-20230420 > [2]: QEMU patch: https://lore.kernel.org/all/20230421041227.90915-1-weijiang.yang@xxxxxxxxx/ > [3]: v1 patchset: https://lore.kernel.org/all/20220616084643.19564-1-weijiang.yang@xxxxxxxxx/ > [4]: Rebase branch: https://github.com/kvm-x86/linux.git, commit: 7b632f72528d (tag: kvm-x86-next-2023.04.14) I played a bit with KVM support for shadow stacks on AMD machines and I rebased v1 patches along with John's SVM series https://lore.kernel.org/kvm/20221012203910.204793-1-john.allen@xxxxxxx/ on top of v6.3-rc4 and Rick's series for host shadow stack support. I've put this at https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=shstk/kvm if anybody is interested. With this I could successfully run shadow stack self test in a guest on an AMD Zen3 machine. One thing I've noticed while rebasing is that John's patches move cet_is_msr_accessible() from vmx/ to x86.c and I also had to make such move for cet_is_ssp_msr_accessible(). Would make sense to have them available for both VMX and SVM from the start. > Rick Edgecombe (5): > x86/shstk: Add Kconfig option for shadow stack > x86/cpufeatures: Add CPU feature flags for shadow stacks > x86/cpufeatures: Enable CET CR4 bit for shadow stack > x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states > x86/fpu: Add helper for modifying xstate > > Sean Christopherson (2): > KVM:x86: Report XSS as to-be-saved if there are supported features > KVM:x86: Load guest FPU state when accessing xsaves-managed MSRs > > Yang Weijiang (14): > KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS > KVM:x86: Init kvm_caps.supported_xss with supported feature bits > KVM:x86: Add #CP support in guest exception classification > KVM:VMX: Introduce CET VMCS fields and control bits > KVM:x86: Add fault checks for guest CR4.CET setting > KVM:VMX: Emulate reads and writes to CET MSRs > KVM:VMX: Add a synthetic MSR to allow userspace VMM to access > GUEST_SSP > KVM:x86: Report CET MSRs as to-be-saved if CET is supported > KVM:x86: Save/Restore GUEST_SSP to/from SMM state save area > KVM:VMX: Pass through user CET MSRs to the guest > KVM:x86: Enable CET virtualization for VMX and advertise to userspace > KVM:nVMX: Enable user CET support for nested VMX > KVM:x86: Enable supervisor IBT support for guest > KVM:x86: Support CET supervisor shadow stack MSR access > > arch/x86/Kconfig | 24 ++++ > arch/x86/Kconfig.assembler | 5 + > arch/x86/include/asm/cpufeatures.h | 2 + > arch/x86/include/asm/disabled-features.h | 8 +- > arch/x86/include/asm/fpu/api.h | 9 ++ > arch/x86/include/asm/fpu/types.h | 16 ++- > arch/x86/include/asm/fpu/xstate.h | 6 +- > arch/x86/include/asm/kvm_host.h | 3 +- > arch/x86/include/asm/vmx.h | 8 ++ > arch/x86/include/uapi/asm/kvm.h | 1 + > arch/x86/include/uapi/asm/kvm_para.h | 1 + > arch/x86/kernel/cpu/common.c | 35 ++++-- > arch/x86/kernel/cpu/cpuid-deps.c | 1 + > arch/x86/kernel/fpu/core.c | 19 +++ > arch/x86/kernel/fpu/xstate.c | 90 +++++++------- > arch/x86/kvm/cpuid.c | 23 +++- > arch/x86/kvm/cpuid.h | 6 + > arch/x86/kvm/smm.c | 20 +++ > arch/x86/kvm/vmx/capabilities.h | 4 + > arch/x86/kvm/vmx/nested.c | 29 ++++- > arch/x86/kvm/vmx/vmcs12.c | 6 + > arch/x86/kvm/vmx/vmcs12.h | 14 ++- > arch/x86/kvm/vmx/vmx.c | 150 ++++++++++++++++++++++- > arch/x86/kvm/vmx/vmx.h | 6 +- > arch/x86/kvm/x86.c | 79 ++++++++++-- > arch/x86/kvm/x86.h | 46 ++++++- > 26 files changed, 528 insertions(+), 83 deletions(-) > > > base-commit: 7b632f72528d5fa3f0265358a393f534da47d9dd > -- > 2.27.0 > -- Sincerely yours, Mike.
