[RFC PATCH v3 07/59] KVM: TDX: Add helper functions to print TDX SEAMCALL error

[isaku.yamahata@xxxxxxxxx]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Add helper functions to print out errors from the TDX module in an uniform
way.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
 arch/x86/kvm/Makefile        |  1 +
 arch/x86/kvm/vmx/seamcall.h  |  3 ++
 arch/x86/kvm/vmx/tdx_error.c | 53 ++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 arch/x86/kvm/vmx/tdx_error.c

diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 75dfd27b6e8a..c7eceff49e67 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -29,6 +29,7 @@ kvm-$(CONFIG_KVM_XEN)	+= xen.o
 kvm-intel-y		+= vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
 			   vmx/evmcs.o vmx/nested.o vmx/posted_intr.o
 kvm-intel-$(CONFIG_X86_SGX_KVM)	+= vmx/sgx.o
+kvm-intel-$(CONFIG_INTEL_TDX_HOST)	+= vmx/tdx_error.o
 
 kvm-amd-y		+= svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o svm/sev.o
 
diff --git a/arch/x86/kvm/vmx/seamcall.h b/arch/x86/kvm/vmx/seamcall.h
index f27e9d27137d..5fa948054be6 100644
--- a/arch/x86/kvm/vmx/seamcall.h
+++ b/arch/x86/kvm/vmx/seamcall.h
@@ -106,6 +106,9 @@ static inline u64 seamcall(u64 op, u64 rcx, u64 rdx, u64 r8, u64 r9, u64 r10,
 	return ret;
 }
 
+void pr_tdx_ex_ret_info(u64 op, u64 error_code, const struct tdx_ex_ret *ex_ret);
+void pr_tdx_error(u64 op, u64 error_code, const struct tdx_ex_ret *ex_ret);
+
 #endif /* !__ASSEMBLER__ */
 
 #endif	/* CONFIG_INTEL_TDX_HOST */
diff --git a/arch/x86/kvm/vmx/tdx_error.c b/arch/x86/kvm/vmx/tdx_error.c
new file mode 100644
index 000000000000..1a4f91397758
--- /dev/null
+++ b/arch/x86/kvm/vmx/tdx_error.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+/* functions to record TDX SEAMCALL error */
+
+#include <linux/kernel.h>
+#include <linux/bug.h>
+
+#include "tdx_errno.h"
+#include "tdx_arch.h"
+#include "tdx_ops.h"
+
+static const char * const TDX_SEPT_ENTRY_STATES[] = {
+	"SEPT_FREE",
+	"SEPT_BLOCKED",
+	"SEPT_PENDING",
+	"SEPT_PENDING_BLOCKED",
+	"SEPT_PRESENT"
+};
+
+void pr_tdx_ex_ret_info(u64 op, u64 error_code, const struct tdx_ex_ret *ex_ret)
+{
+	if (WARN_ON(!ex_ret))
+		return;
+
+	switch (error_code & TDX_SEAMCALL_STATUS_MASK) {
+	case TDX_EPT_WALK_FAILED: {
+		const char *state;
+
+		if (ex_ret->sept_walk.state >= ARRAY_SIZE(TDX_SEPT_ENTRY_STATES))
+			state = "Invalid";
+		else
+			state = TDX_SEPT_ENTRY_STATES[ex_ret->sept_walk.state];
+
+		pr_err("Secure EPT walk error: SEPTE 0x%llx, level %d, %s\n",
+			ex_ret->sept_walk.septe, ex_ret->sept_walk.level, state);
+		break;
+	}
+	default:
+		/* TODO: print only meaningful registers depending on op */
+		pr_err("RCX 0x%llx, RDX 0x%llx, R8 0x%llx, R9 0x%llx, "
+		       "R10 0x%llx, R11 0x%llx\n",
+			ex_ret->regs.rcx, ex_ret->regs.rdx, ex_ret->regs.r8,
+			ex_ret->regs.r9, ex_ret->regs.r10, ex_ret->regs.r11);
+		break;
+	}
+}
+
+void pr_tdx_error(u64 op, u64 error_code, const struct tdx_ex_ret *ex_ret)
+{
+	pr_err_ratelimited("SEAMCALL[0x%llx] failed: 0x%llx\n",
+			op, error_code);
+	if (ex_ret)
+		pr_tdx_ex_ret_info(op, error_code, ex_ret);
+}
-- 
2.25.1