From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> On EPT violation, call a common function, __vmx_handle_ept_violation() to trigger x86 MMU code. On EPT misconfiguration, exit to ring 3 with KVM_EXIT_UNKNOWN. because EPT misconfiguration can't happen as MMIO is trigged by TDG.VP.VMCALL. No point to set a misconfiguration value for the fast path. Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> --- v14 -> v15: - use PFERR_GUEST_ENC_MASK to tell the fault is private Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> --- arch/x86/kvm/vmx/common.h | 3 +++ arch/x86/kvm/vmx/tdx.c | 46 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h index aaab1d407207..e4fec792a3ae 100644 --- a/arch/x86/kvm/vmx/common.h +++ b/arch/x86/kvm/vmx/common.h @@ -87,6 +87,9 @@ static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa, error_code |= (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) != 0 ? PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK; + if (kvm_is_private_gpa(vcpu->kvm, gpa)) + error_code |= PFERR_GUEST_ENC_MASK; + return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0); } diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 0d92253ea40e..1a41e12f0942 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1136,6 +1136,48 @@ void tdx_deliver_interrupt(struct kvm_lapic *apic, int delivery_mode, __vmx_deliver_posted_interrupt(vcpu, &tdx->pi_desc, vector); } +static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu) +{ + unsigned long exit_qual; + + if (kvm_is_private_gpa(vcpu->kvm, tdexit_gpa(vcpu))) { + /* + * Always treat SEPT violations as write faults. Ignore the + * EXIT_QUALIFICATION reported by TDX-SEAM for SEPT violations. + * TD private pages are always RWX in the SEPT tables, + * i.e. they're always mapped writable. Just as importantly, + * treating SEPT violations as write faults is necessary to + * avoid COW allocations, which will cause TDAUGPAGE failures + * due to aliasing a single HPA to multiple GPAs. + */ +#define TDX_SEPT_VIOLATION_EXIT_QUAL EPT_VIOLATION_ACC_WRITE + exit_qual = TDX_SEPT_VIOLATION_EXIT_QUAL; + } else { + exit_qual = tdexit_exit_qual(vcpu); + if (exit_qual & EPT_VIOLATION_ACC_INSTR) { + pr_warn("kvm: TDX instr fetch to shared GPA = 0x%lx @ RIP = 0x%lx\n", + tdexit_gpa(vcpu), kvm_rip_read(vcpu)); + vcpu->run->exit_reason = KVM_EXIT_EXCEPTION; + vcpu->run->ex.exception = PF_VECTOR; + vcpu->run->ex.error_code = exit_qual; + return 0; + } + } + + trace_kvm_page_fault(vcpu, tdexit_gpa(vcpu), exit_qual); + return __vmx_handle_ept_violation(vcpu, tdexit_gpa(vcpu), exit_qual); +} + +static int tdx_handle_ept_misconfig(struct kvm_vcpu *vcpu) +{ + WARN_ON_ONCE(1); + + vcpu->run->exit_reason = KVM_EXIT_UNKNOWN; + vcpu->run->hw.hardware_exit_reason = EXIT_REASON_EPT_MISCONFIG; + + return 0; +} + int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath) { union tdx_exit_reason exit_reason = to_tdx(vcpu)->exit_reason; @@ -1196,6 +1238,10 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath) WARN_ON_ONCE(fastpath != EXIT_FASTPATH_NONE); switch (exit_reason.basic) { + case EXIT_REASON_EPT_VIOLATION: + return tdx_handle_ept_violation(vcpu); + case EXIT_REASON_EPT_MISCONFIG: + return tdx_handle_ept_misconfig(vcpu); case EXIT_REASON_OTHER_SMI: /* * If reach here, it's not a Machine Check System Management -- 2.25.1