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Subject[PATCH v2 2/6] x86/tdx: Add GetQuote TDX hypercall support
Date
The second stage in the attestation process is for the guest to
request the VMM generate and sign a quote based on the TDREPORT
acquired earlier.

Add tdx_hcall_get_quote() helper function to implement the GetQuote
hypercall.

More details about the GetQuote TDVMCALL are in the Guest-Host
Communication Interface (GHCI) Specification, sec 3.3, titled
"TDG.VP.VMCALL<GetQuote>".

This will be used by the TD attestation driver in follow-on patches.

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 | 30 ++++++++++++++++++++++++++++++
2 files changed, 32 insertions(+)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 4f1b5c14a09b..1599aa4850e5 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -98,6 +98,8 @@ bool tdg_filter_enabled(void);

int tdx_mcall_tdreport(u64 data, u64 reportdata);

+int tdx_hcall_get_quote(u64 data);
+
/*
* 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 0f797803f4c8..eb3a90051604 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -28,6 +28,7 @@

/* TDX hypercall Leaf IDs */
#define TDVMCALL_MAP_GPA 0x10001
+#define TDVMCALL_GET_QUOTE 0x10002

/* TDX Module call error codes */
#define TDX_PAGE_ALREADY_ACCEPTED 0x8000000000000001
@@ -36,6 +37,9 @@
#define TDCALL_INVALID_OPERAND 0x8000000000000000
#define TDCALL_RETURN_CODE(a) ((a) & TDCALL_RETURN_CODE_MASK)

+/* TDX hypercall error codes */
+#define TDVMCALL_INVALID_OPERAND 0x8000000000000000
+#define TDVMCALL_TDREPORT_FAILED 0x8000000000000001

#define VE_IS_IO_OUT(exit_qual) (((exit_qual) & 8) ? 0 : 1)
#define VE_GET_IO_SIZE(exit_qual) (((exit_qual) & 7) + 1)
@@ -172,6 +176,32 @@ int tdx_mcall_tdreport(u64 data, u64 reportdata)
}
EXPORT_SYMBOL_GPL(tdx_mcall_tdreport);

+/*
+ * tdx_hcall_get_quote() - Generate TDQUOTE using TDREPORT_STRUCT.
+ *
+ * @data : Physical address of 4KB GPA memory which contains
+ * TDREPORT_STRUCT.
+ *
+ * return 0 on success or failure error number.
+ */
+int tdx_hcall_get_quote(u64 data)
+{
+ u64 ret;
+
+ if (!data || !prot_guest_has(PR_GUEST_TDX))
+ return -EINVAL;
+
+ ret = _trace_tdx_hypercall(TDVMCALL_GET_QUOTE, data, 0, 0, 0, NULL);
+
+ if (ret == TDVMCALL_INVALID_OPERAND)
+ return -EINVAL;
+ else if (ret == TDVMCALL_TDREPORT_FAILED)
+ return -EBUSY;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tdx_hcall_get_quote);
+
static void tdg_get_info(void)
{
u64 ret;
--
2.25.1
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