linux-kernel - [PATCH 08/18] KVM: TDX: Handle TDX PV rdmsr/wrmsr hypercall

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Message-ID: <20241210004946.3718496-9-binbin.wu@linux.intel.com>
Date: Tue, 10 Dec 2024 08:49:34 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: pbonzini@...hat.com,
	seanjc@...gle.com,
	kvm@...r.kernel.org
Cc: rick.p.edgecombe@...el.com,
	kai.huang@...el.com,
	adrian.hunter@...el.com,
	reinette.chatre@...el.com,
	xiaoyao.li@...el.com,
	tony.lindgren@...ux.intel.com,
	isaku.yamahata@...el.com,
	yan.y.zhao@...el.com,
	chao.gao@...el.com,
	linux-kernel@...r.kernel.org,
	binbin.wu@...ux.intel.com
Subject: [PATCH 08/18] KVM: TDX: Handle TDX PV rdmsr/wrmsr hypercall

From: Isaku Yamahata <isaku.yamahata@...el.com>

Wire up TDX PV rdmsr/wrmsr hypercall to the KVM backend function.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Binbin Wu <binbin.wu@...ux.intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
---
TDX "the rest" breakout:
- Use TDVMCALL_STATUS prefix for TDX call status codes (Binbin)
---
 arch/x86/kvm/vmx/tdx.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 770e3b847cd6..d5343e2ba509 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1493,6 +1493,41 @@ static int tdx_emulate_mmio(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int tdx_emulate_rdmsr(struct kvm_vcpu *vcpu)
+{
+	u32 index = tdvmcall_a0_read(vcpu);
+	u64 data;
+
+	if (!kvm_msr_allowed(vcpu, index, KVM_MSR_FILTER_READ) ||
+	    kvm_get_msr(vcpu, index, &data)) {
+		trace_kvm_msr_read_ex(index);
+		tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
+		return 1;
+	}
+	trace_kvm_msr_read(index, data);
+
+	tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUCCESS);
+	tdvmcall_set_return_val(vcpu, data);
+	return 1;
+}
+
+static int tdx_emulate_wrmsr(struct kvm_vcpu *vcpu)
+{
+	u32 index = tdvmcall_a0_read(vcpu);
+	u64 data = tdvmcall_a1_read(vcpu);
+
+	if (!kvm_msr_allowed(vcpu, index, KVM_MSR_FILTER_WRITE) ||
+	    kvm_set_msr(vcpu, index, data)) {
+		trace_kvm_msr_write_ex(index, data);
+		tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_INVALID_OPERAND);
+		return 1;
+	}
+
+	trace_kvm_msr_write(index, data);
+	tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUCCESS);
+	return 1;
+}
+
 static int handle_tdvmcall(struct kvm_vcpu *vcpu)
 {
 	if (tdvmcall_exit_type(vcpu))
@@ -1511,6 +1546,10 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu)
 		return tdx_emulate_io(vcpu);
 	case EXIT_REASON_EPT_VIOLATION:
 		return tdx_emulate_mmio(vcpu);
+	case EXIT_REASON_MSR_READ:
+		return tdx_emulate_rdmsr(vcpu);
+	case EXIT_REASON_MSR_WRITE:
+		return tdx_emulate_wrmsr(vcpu);
 	default:
 		break;
 	}
-- 
2.46.0