Re: [RFC PATCH v5 093/104] KVM: TDX: Handle TDX PV port io hypercall

From: Paolo Bonzini
Date: Fri Apr 15 2022 - 10:59:31 EST


On 3/4/22 20:49, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Wire up TDX PV port IO hypercall to the KVM backend function.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/kvm/vmx/tdx.c | 55 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index b0dcc2421649..c900347d0bc7 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -959,6 +959,59 @@ static int tdx_emulate_hlt(struct kvm_vcpu *vcpu)
return kvm_emulate_halt_noskip(vcpu);
}
+static int tdx_complete_pio_in(struct kvm_vcpu *vcpu)
+{
+ struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;
+ unsigned long val = 0;
+ int ret;
+
+ WARN_ON(vcpu->arch.pio.count != 1);
+
+ ret = ctxt->ops->pio_in_emulated(ctxt, vcpu->arch.pio.size,
+ vcpu->arch.pio.port, &val, 1);
+ WARN_ON(!ret);
+
+ tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
+ tdvmcall_set_return_val(vcpu, val);
+
+ return 1;
+}
+
+static int tdx_emulate_io(struct kvm_vcpu *vcpu)
+{
+ struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt;
+ unsigned long val = 0;
+ unsigned int port;
+ int size, ret;
+
+ ++vcpu->stat.io_exits;
+
+ size = tdvmcall_p1_read(vcpu);
+ port = tdvmcall_p3_read(vcpu);
+
+ if (size != 1 && size != 2 && size != 4) {
+ tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_INVALID_OPERAND);
+ return 1;
+ }
+
+ if (!tdvmcall_p2_read(vcpu)) {
+ ret = ctxt->ops->pio_in_emulated(ctxt, size, port, &val, 1);
+ if (!ret)
+ vcpu->arch.complete_userspace_io = tdx_complete_pio_in;
+ else
+ tdvmcall_set_return_val(vcpu, val);
+ } else {
+ val = tdvmcall_p4_read(vcpu);
+ ret = ctxt->ops->pio_out_emulated(ctxt, size, port, &val, 1);
+
+ /* No need for a complete_userspace_io callback. */
+ vcpu->arch.pio.count = 0;
+ }
+ if (ret)
+ tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_SUCCESS);
+ return ret;
+}
+
static int handle_tdvmcall(struct kvm_vcpu *vcpu)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
@@ -974,6 +1027,8 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu)
return tdx_emulate_cpuid(vcpu);
case EXIT_REASON_HLT:
return tdx_emulate_hlt(vcpu);
+ case EXIT_REASON_IO_INSTRUCTION:
+ return tdx_emulate_io(vcpu);
default:
break;
}

Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>