Messages in this thread | | | Date | Tue, 25 Jul 2023 17:07:06 +0800 | Subject | Re: [RFC PATCH v4 09/10] KVM: x86: Make struct sev_cmd common for KVM_MEM_ENC_OP | From | Xiaoyao Li <> |
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On 7/21/2023 10:51 PM, Sean Christopherson wrote: > On Thu, Jul 20, 2023, isaku.yamahata@intel.com wrote: >> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h >> index aa7a56a47564..32883e520b00 100644 >> --- a/arch/x86/include/uapi/asm/kvm.h >> +++ b/arch/x86/include/uapi/asm/kvm.h >> @@ -562,6 +562,39 @@ struct kvm_pmu_event_filter { >> /* x86-specific KVM_EXIT_HYPERCALL flags. */ >> #define KVM_EXIT_HYPERCALL_LONG_MODE BIT(0) >> >> +struct kvm_mem_enc_cmd { >> + /* sub-command id of KVM_MEM_ENC_OP. */ >> + __u32 id; >> + /* >> + * Auxiliary flags for sub-command. If sub-command doesn't use it, >> + * set zero. >> + */ >> + __u32 flags; >> + /* >> + * Data for sub-command. An immediate or a pointer to the actual >> + * data in process virtual address. If sub-command doesn't use it, >> + * set zero. >> + */ >> + __u64 data; >> + /* >> + * Supplemental error code in the case of error. >> + * SEV error code from the PSP or TDX SEAMCALL status code. >> + * The caller should set zero. >> + */ >> + union { >> + struct { >> + __u32 error; >> + /* >> + * KVM_SEV_LAUNCH_START and KVM_SEV_RECEIVE_START >> + * require extra data. Not included in struct >> + * kvm_sev_launch_start or struct kvm_sev_receive_start. >> + */ >> + __u32 sev_fd; >> + }; >> + __u64 error64; >> + }; >> +}; > > Eww. Why not just use an entirely different struct for TDX? I don't see what > benefit this provides other than a warm fuzzy feeling that TDX and SEV share a > struct. Practically speaking, KVM will likely take on more work to forcefully > smush the two together than if they're separate things.
generalizing the struct of KVM_MEM_ENC_OP should be the first step. The final target should be generalizing a set of commands for confidential VMs (SEV-* VMs and TDs, maybe even for other arches), e.g., the commands to create a confidential VM and commands to live migration a confidential VM.
However, there seems not small divergence between the commands to create a SEV-* VM and TDX VMs. I'm not sure if it is worth investigating and pursuing.
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