RE: [RFC PATCH 0/4] TDX KVM selftests

["Duan, Zhenzhong" <zhenzhong.duan@intel.com>]

> -----Original Message-----
> From: Erdem Aktas <erdemaktas@google.com>
> Sent: Tuesday, July 27, 2021 2:38 AM
> To: linux-kselftest@vger.kernel.org
> Cc: erdemaktas@google.com; Paolo Bonzini <pbonzini@redhat.com>; Shuah
> Khan <shuah@kernel.org>; Andrew Jones <drjones@redhat.com>; Ben
> Gardon <bgardon@google.com>; Peter Xu <peterx@redhat.com>; Sean
> Christopherson <seanjc@google.com>; Christian Borntraeger
> <borntraeger@de.ibm.com>; Eric Auger <eric.auger@redhat.com>;
> Emanuele Giuseppe Esposito <eesposit@redhat.com>; Ricardo Koller
> <ricarkol@google.com>; Duan, Zhenzhong <zhenzhong.duan@intel.com>;
> Aaron Lewis <aaronlewis@google.com>; Jim Mattson
> <jmattson@google.com>; Oliver Upton <oupton@google.com>; Vitaly
> Kuznetsov <vkuznets@redhat.com>; Peter Shier <pshier@google.com>; Axel
> Rasmussen <axelrasmussen@google.com>; Yanan Wang
> <wangyanan55@huawei.com>; Maciej S. Szmigiero
> <maciej.szmigiero@oracle.com>; David Matlack <dmatlack@google.com>;
> Like Xu <like.xu@linux.intel.com>; open list <linux-kernel@vger.kernel.org>;
> open list:KERNEL VIRTUAL MACHINE (KVM) <kvm@vger.kernel.org>
> Subject: [RFC PATCH 0/4] TDX KVM selftests
> 
> TDX stands for Trust Domain Extensions which isolates VMs from the virtual-
> machine manager (VMM)/hypervisor and any other software on the
> platform.
> 
> Intel has recently submitted a set of RFC patches for KVM support for TDX
> and more information can be found on the latest TDX Support
> Patches: https://lkml.org/lkml/2021/7/2/558
> 
> Due to the nature of the confidential computing environment that TDX
> provides, it is very difficult to verify/test the KVM support. TDX requires UEFI
> and the guest kernel to be enlightened which are all under development.
> 
> We are working on a set of selftests to close this gap and be able to verify the
> KVM functionality to support TDX lifecycle and GHCI [1] interface.
> 
> We are looking for any feedback on:
> - Patch series itself
> - Any suggestion on how we should approach testing TDX functionality.
> Does selftests seems reasonable or should we switch to using KVM unit tests.
> I would be happy to get some perspective on how KVM unit tests can help us
> more.
> - Any test case or scenario that we should add.
> - Anything else I have not thought of yet.
> 
> Current patch series provide the following capabilities:
> 
> - Provide helper functions to create a TD (Trusted Domain) using the KVM
>   ioctls
> - Provide helper functions to create a guest image that can include any
>   testing code
> - Provide helper functions and wrapper functions to write testing code
>   using GHCI interface
> - Add a test case that verifies TDX life cycle
> - Add a test case that verifies TDX GHCI port IO
> 
> TODOs:
> - Use existing function to create page tables dynamically
>   (ie __virt_pg_map())
> - Remove arbitrary defined magic numbers for data structure offsets
> - Add TDVMCALL for error reporting
> - Add additional test cases as some listed below
> - Add #VE handlers to help testing more complicated test cases
> 
> Other test cases that we are planning to add:
> (with credit to sagis@google.com)
> 
> VM call interface        Input                        Output                Result
> GetTdVmCallInfo          R12=0                        None                VMCALL_SUCCESS
> MapGPA                   Map private page (GPA.S=0)
> VMCALL_SUCCESS
> MapGPA                   Map shared page (GPA.S=1)
> VMCALL_SUCCESS
> MapGPA                   Map already private page as private
> VMCALL_INVALID_OPERAND
> MapGPA                   Map already shared page as shared
> VMCALL_INVALID_OPERAND
> GetQuote
> ReportFatalError
> SetupEventNotifyInterrupt   Valid interrupt value (32:255)
> VMCALL_SUCCESS
> SetupEventNotifyInterrupt   Invalid value (>255)
> VMCALL_INVALID_OPERAND
> Instruction.CPUID        R12(EAX)=1, R13(ECX)=0       EBX[8:15]=0x8
>                                                       EBX[16:23]=X
>                                                       EBX[24:31]=vcpu_id
>                                                       ECX[0]=1
>                                                       ECX[12]=Y
> Instruction.CPUID       R12(EAX)=1, R13(ECX)=4
> VMCALL_INVALID_OPERAND
> VE.RequestMMIO
> Instruction.HLT                                                           VMCALL_SUCCESS
> Instruction.IO          Read/Write 1/2/4 bytes                            VMCALL_SUCCESS
> Instruction.IO          Read/Write 3 bytes
> VMCALL_INVALID_OPERAND
> Instruction.RDMSR       Accessible register           R11=msr_value
> VMCALL_SUCCESS
>                         Inaccessible register
> VMCALL_INVALID_OPERAND
> Instruction.RDMSR       Accessible register                               VMCALL_SUCCESS
>                         Inaccessible register
> VMCALL_INVALID_OPERAND
> INSTRUCTION.PCONFIG
> 
> [1] Intel TDX Guest-Hypervisor Communication Interface
> 
> https://software.intel.com/content/dam/develop/external/us/en/document
> s/intel-tdx-guest-hypervisor-communication-interface.pdf
> 
> 
> Erdem Aktas (4):
>   KVM: selftests: Add support for creating non-default type VMs
>   KVM: selftest: Add helper functions to create TDX VMs
In tools/testing/selftests/kvm/Makefile, '/lib/x86_64/tdx_lib.c' should be changed to 'lib/x86_64/tdx_lib.c'
After that, build and test passes.

# ./tdx_vm_tests
Verifying TD lifecycle:
Verifying TD IO Exit:
         ... IO WRITE: OK
         ... IO READ: OK
         ... IO verify read/write values: OK

Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

Regards
Zhenzhong