Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 17 Jun 2024 17:07:56 +0800 | Subject | Re: [PATCH v19 085/130] KVM: TDX: Complete interrupts after tdexit | From | Binbin Wu <> |
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On 6/17/2024 4:07 PM, Yuan Yao wrote: > On Mon, Feb 26, 2024 at 12:26:27AM -0800, isaku.yamahata@intel.com wrote: >> From: Isaku Yamahata <isaku.yamahata@intel.com> >> >> This corresponds to VMX __vmx_complete_interrupts(). Because TDX >> virtualize vAPIC, KVM only needs to care NMI injection. >> >> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> >> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> >> --- >> v19: >> - move tdvps_management_check() to this patch >> - typo: complete -> Complete in short log >> --- >> arch/x86/kvm/vmx/tdx.c | 10 ++++++++++ >> arch/x86/kvm/vmx/tdx.h | 4 ++++ >> 2 files changed, 14 insertions(+) >> >> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c >> index 83dcaf5b6fbd..b8b168f74dfe 100644 >> --- a/arch/x86/kvm/vmx/tdx.c >> +++ b/arch/x86/kvm/vmx/tdx.c >> @@ -535,6 +535,14 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) >> */ >> } >> >> +static void tdx_complete_interrupts(struct kvm_vcpu *vcpu) >> +{ >> + /* Avoid costly SEAMCALL if no nmi was injected */ >> + if (vcpu->arch.nmi_injected) >> + vcpu->arch.nmi_injected = td_management_read8(to_tdx(vcpu), >> + TD_VCPU_PEND_NMI); >> +} > Looks this leads to NMI injection delay or even won't be > reinjected if KVM_REQ_EVENT is not set on the target cpu > when more than 1 NMIs are pending there. > > On normal VM, KVM uses NMI window vmexit for injection > successful case to rasie the KVM_REQ_EVENT again for remain > pending NMIs, see handle_nmi_window(). KVM also checks > vectoring info after VMEXIT for case that the NMI is not > injected successfully in this vmentry vmexit round, and > raise KVM_REQ_EVENT to try again, see __vmx_complete_interrupts(). > > In TDX, consider there's no way to get vectoring info or > handle nmi window vmexit, below checking should cover both > scenarios for NMI injection: > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index e9c9a185bb7b..9edf446acd3b 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -835,9 +835,12 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > static void tdx_complete_interrupts(struct kvm_vcpu *vcpu) > { > /* Avoid costly SEAMCALL if no nmi was injected */ > - if (vcpu->arch.nmi_injected) > + if (vcpu->arch.nmi_injected) { > vcpu->arch.nmi_injected = td_management_read8(to_tdx(vcpu), > TD_VCPU_PEND_NMI); > + if (vcpu->arch.nmi_injected || vcpu->arch.nmi_pending) > + kvm_make_request(KVM_REQ_EVENT, vcpu);
For nmi_injected, it should be OK because TD_VCPU_PEND_NMI is still set. But for nmi_pending, it should be checked and raise event.
I remember there was a discussion in the following link: https://lore.kernel.org/kvm/20240402065254.GY2444378@ls.amr.corp.intel.com/ It said tdx_vcpu_run() will ignore force_immediate_exit. If force_immediate_exit is igored for TDX, then the nmi_pending handling could still be delayed if the previous NMI was injected successfully.
> + } > } > >> + >> struct tdx_uret_msr { >> u32 msr; >> unsigned int slot; >> @@ -663,6 +671,8 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) >> vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; >> trace_kvm_exit(vcpu, KVM_ISA_VMX); >> >> + tdx_complete_interrupts(vcpu); >> + >> return EXIT_FASTPATH_NONE; >> } >> >> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h >> index 44eab734e702..0d8a98feb58e 100644 >> --- a/arch/x86/kvm/vmx/tdx.h >> +++ b/arch/x86/kvm/vmx/tdx.h >> @@ -142,6 +142,8 @@ static __always_inline void tdvps_vmcs_check(u32 field, u8 bits) >> "Invalid TD VMCS access for 16-bit field"); >> } >> >> +static __always_inline void tdvps_management_check(u64 field, u8 bits) {} >> + >> #define TDX_BUILD_TDVPS_ACCESSORS(bits, uclass, lclass) \ >> static __always_inline u##bits td_##lclass##_read##bits(struct vcpu_tdx *tdx, \ >> u32 field) \ >> @@ -200,6 +202,8 @@ TDX_BUILD_TDVPS_ACCESSORS(16, VMCS, vmcs); >> TDX_BUILD_TDVPS_ACCESSORS(32, VMCS, vmcs); >> TDX_BUILD_TDVPS_ACCESSORS(64, VMCS, vmcs); >> >> +TDX_BUILD_TDVPS_ACCESSORS(8, MANAGEMENT, management); >> + >> static __always_inline u64 td_tdcs_exec_read64(struct kvm_tdx *kvm_tdx, u32 field) >> { >> struct tdx_module_args out; >> -- >> 2.25.1 >> >>
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