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[192.55.54.37]) by smtp.gmail.com with ESMTPSA id ms9-20020a17090b234900b001ec7c8919f0sm1678613pjb.23.2022.06.29.03.17.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Jun 2022 03:17:45 -0700 (PDT) Date: Wed, 29 Jun 2022 03:17:44 -0700 From: Isaku Yamahata To: Sagi Shahar Cc: "Yamahata, Isaku" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, isaku.yamahata@gmail.com, Paolo Bonzini , Erdem Aktas , Sean Christopherson Subject: Re: [RFC PATCH v6 093/104] KVM: TDX: Handle TDX PV MMIO hypercall Message-ID: <20220629101744.GB882746@ls.amr.corp.intel.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 14, 2022 at 11:08:16AM -0700, Sagi Shahar wrote: > On Thu, May 5, 2022 at 11:16 AM wrote: > > > > From: Sean Christopherson > > > > 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 > > Signed-off-by: Isaku Yamahata > > Reviewed-by: Paolo Bonzini > > --- > > 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 ee0cf5336ade..6ab4a52fc9e9 100644 > > --- a/arch/x86/kvm/vmx/tdx.c > > +++ b/arch/x86/kvm/vmx/tdx.c > > @@ -1057,6 +1057,118 @@ 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; > > + > > + WARN_ON(vcpu->mmio_needed != 1); > > + 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; > > + > > + WARN_ON(vcpu->mmio_needed); > > + > > + 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_SUCCESS); > > We should return an error code here. Yes, I'll fix it as follows. Thanks for catching it. error: - tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS); + tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_INVALID_OPERAND); return 1; } -- Isaku Yamahata