Commit Message
Isaku Yamahata
Oct. 30, 2022, 6:23 a.m. UTC
From: Isaku Yamahata <isaku.yamahata@intel.com> 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@intel.com> --- arch/x86/kvm/vmx/tdx.c | 46 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 68d9d590ca8f..4a95db961f82 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1046,6 +1046,48 @@ 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; @@ -1068,6 +1110,10 @@ 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