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Subject[PATCH v2 1/6] x86/tdx: Add TDREPORT TDX Module call support
Date
The TDX Guest-Host Communication Interface (GHCI) includes a module
call (TDREPORT TDCALL) that a guest can make to acquire a copy of the
attestation data that it needs to verify its trustworthiness.

Add a wrapper function tdx_mcall_tdreport() that makes the module
call to get this data.

See GHCI section 2.4.5 "TDCALL [TDG.MR.REPORT] leaf" for additional
details.

[Xiaoyao: Proposed error code fix]
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
arch/x86/include/asm/tdx.h | 2 ++
arch/x86/kernel/tdx.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 48927fac9e12..4f1b5c14a09b 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -96,6 +96,8 @@ extern int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,

bool tdg_filter_enabled(void);

+int tdx_mcall_tdreport(u64 data, u64 reportdata);
+
/*
* To support I/O port access in decompressor or early kernel init
* code, since #VE exception handler cannot be used, use paravirt
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index f76af7661046..0f797803f4c8 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -23,6 +23,7 @@
/* TDX Module call Leaf IDs */
#define TDINFO 1
#define TDGETVEINFO 3
+#define TDREPORT 4
#define TDACCEPTPAGE 6

/* TDX hypercall Leaf IDs */
@@ -30,6 +31,11 @@

/* TDX Module call error codes */
#define TDX_PAGE_ALREADY_ACCEPTED 0x8000000000000001
+#define TDCALL_RETURN_CODE_MASK 0xFFFFFFFF00000000
+#define TDCALL_OPERAND_BUSY 0x8000020000000000
+#define TDCALL_INVALID_OPERAND 0x8000000000000000
+#define TDCALL_RETURN_CODE(a) ((a) & TDCALL_RETURN_CODE_MASK)
+

#define VE_IS_IO_OUT(exit_qual) (((exit_qual) & 8) ? 0 : 1)
#define VE_GET_IO_SIZE(exit_qual) (((exit_qual) & 7) + 1)
@@ -139,6 +145,33 @@ static bool tdg_perfmon_enabled(void)
return td_info.attributes & BIT(63);
}

+/*
+ * tdx_mcall_tdreport() - Generate TDREPORT_STRUCT using TDCALL.
+ *
+ * @data : Physical address of 1024B aligned data to store
+ * TDREPORT_STRUCT.
+ * @reportdata : Physical address of 64B aligned report data
+ *
+ * return 0 on success or failure error number.
+ */
+int tdx_mcall_tdreport(u64 data, u64 reportdata)
+{
+ u64 ret;
+
+ if (!data || !reportdata || !prot_guest_has(PR_GUEST_TDX))
+ return -EINVAL;
+
+ ret = __trace_tdx_module_call(TDREPORT, data, reportdata, 0, 0, NULL);
+
+ if (TDCALL_RETURN_CODE(ret) == TDCALL_INVALID_OPERAND)
+ return -EINVAL;
+ else if (TDCALL_RETURN_CODE(ret) == TDCALL_OPERAND_BUSY)
+ return -EBUSY;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tdx_mcall_tdreport);
+
static void tdg_get_info(void)
{
u64 ret;
--
2.25.1
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