From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Export kvm_io_bus_read and kvm_mmio tracepoint and wire up TDX PV MMIO hypercall to the KVM backend functions. kvm_io_bus_read/write() searches KVM device emulated in kernel of the given MMIO address and emulates the MMIO. As TDX PV MMIO also needs it, export kvm_io_bus_read(). kvm_io_bus_write() is already exported. TDX PV MMIO emulates some of MMIO itself. To add trace point consistently with x86 kvm, export kvm_mmio tracepoint. Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> --- arch/x86/kvm/vmx/tdx.c | 114 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 1 + virt/kvm/kvm_main.c | 2 + 3 files changed, 117 insertions(+) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 164a84f357ab..a3ea6fe021c1 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1093,6 +1093,118 @@ static int tdx_emulate_io(struct kvm_vcpu *vcpu) return ret; } +static int tdx_complete_mmio(struct kvm_vcpu *vcpu) +{ + unsigned long val = 0; + gpa_t gpa; + int size; + + KVM_BUG_ON(vcpu->mmio_needed != 1, vcpu->kvm); + vcpu->mmio_needed = 0; + + if (!vcpu->mmio_is_write) { + gpa = vcpu->mmio_fragments[0].gpa; + size = vcpu->mmio_fragments[0].len; + + memcpy(&val, vcpu->run->mmio.data, size); + tdvmcall_set_return_val(vcpu, val); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, size, gpa, &val); + } + return 1; +} + +static inline int tdx_mmio_write(struct kvm_vcpu *vcpu, gpa_t gpa, int size, + unsigned long val) +{ + if (kvm_iodevice_write(vcpu, &vcpu->arch.apic->dev, gpa, size, &val) && + kvm_io_bus_write(vcpu, KVM_MMIO_BUS, gpa, size, &val)) + return -EOPNOTSUPP; + + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, size, gpa, &val); + return 0; +} + +static inline int tdx_mmio_read(struct kvm_vcpu *vcpu, gpa_t gpa, int size) +{ + unsigned long val; + + if (kvm_iodevice_read(vcpu, &vcpu->arch.apic->dev, gpa, size, &val) && + kvm_io_bus_read(vcpu, KVM_MMIO_BUS, gpa, size, &val)) + return -EOPNOTSUPP; + + tdvmcall_set_return_val(vcpu, val); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, size, gpa, &val); + return 0; +} + +static int tdx_emulate_mmio(struct kvm_vcpu *vcpu) +{ + struct kvm_memory_slot *slot; + int size, write, r; + unsigned long val; + gpa_t gpa; + + KVM_BUG_ON(vcpu->mmio_needed, vcpu->kvm); + + size = tdvmcall_a0_read(vcpu); + write = tdvmcall_a1_read(vcpu); + gpa = tdvmcall_a2_read(vcpu); + val = write ? tdvmcall_a3_read(vcpu) : 0; + + if (size != 1 && size != 2 && size != 4 && size != 8) + goto error; + if (write != 0 && write != 1) + goto error; + + /* Strip the shared bit, allow MMIO with and without it set. */ + gpa = gpa & ~gfn_to_gpa(kvm_gfn_shared_mask(vcpu->kvm)); + + if (size > 8u || ((gpa + size - 1) ^ gpa) & PAGE_MASK) + goto error; + + slot = kvm_vcpu_gfn_to_memslot(vcpu, gpa_to_gfn(gpa)); + if (slot && !(slot->flags & KVM_MEMSLOT_INVALID)) + goto error; + + if (!kvm_io_bus_write(vcpu, KVM_FAST_MMIO_BUS, gpa, 0, NULL)) { + trace_kvm_fast_mmio(gpa); + return 1; + } + + if (write) + r = tdx_mmio_write(vcpu, gpa, size, val); + else + r = tdx_mmio_read(vcpu, gpa, size); + if (!r) { + /* Kernel completed device emulation. */ + tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS); + return 1; + } + + /* Request the device emulation to userspace device model. */ + vcpu->mmio_needed = 1; + vcpu->mmio_is_write = write; + vcpu->arch.complete_userspace_io = tdx_complete_mmio; + + vcpu->run->mmio.phys_addr = gpa; + vcpu->run->mmio.len = size; + vcpu->run->mmio.is_write = write; + vcpu->run->exit_reason = KVM_EXIT_MMIO; + + if (write) { + memcpy(vcpu->run->mmio.data, &val, size); + } else { + vcpu->mmio_fragments[0].gpa = gpa; + vcpu->mmio_fragments[0].len = size; + trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, size, gpa, NULL); + } + return 0; + +error: + tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_INVALID_OPERAND); + return 1; +} + static int handle_tdvmcall(struct kvm_vcpu *vcpu) { if (tdvmcall_exit_type(vcpu)) @@ -1105,6 +1217,8 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu) return tdx_emulate_hlt(vcpu); case EXIT_REASON_IO_INSTRUCTION: return tdx_emulate_io(vcpu); + case EXIT_REASON_EPT_VIOLATION: + return tdx_emulate_mmio(vcpu); default: break; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1e166749869f..8d0bc21a905a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -13686,6 +13686,7 @@ EXPORT_SYMBOL_GPL(kvm_sev_es_string_io); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_entry); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit); +EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 295395524335..3eebfa022392 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2538,6 +2538,7 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn return NULL; } +EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot); bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) { @@ -5721,6 +5722,7 @@ int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr, r = __kvm_io_bus_read(vcpu, bus, &range, val); return r < 0 ? r : 0; } +EXPORT_SYMBOL_GPL(kvm_io_bus_read); /* Caller must hold slots_lock. */ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, -- 2.25.1