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From:   Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <mgross@linux.intel.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>
Cc:     Peter H Anvin <hpa@zytor.com>, Dave Hansen <dave.hansen@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>,
        Sean Christopherson <seanjc@google.com>,
        Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
        x86@kernel.org, linux-kernel@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, bpf@vger.kernel.org,
        netdev@vger.kernel.org
Subject: [PATCH v3 3/6] x86/tdx: Add SetupEventNotifyInterrupt TDX hypercall support
Date:   Mon, 19 Jul 2021 21:55:49 -0700
Message-Id: <20210720045552.2124688-4-sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <20210720045552.2124688-1-sathyanarayanan.kuppuswamy@linux.intel.com>
References: <20210720045552.2124688-1-sathyanarayanan.kuppuswamy@linux.intel.com>
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SetupEventNotifyInterrupt TDX hypercall is used by guest TD to specify
which interrupt vector to use as an event-notify vector to the VMM.
Such registered vector is also used by Host VMM to notify about
completion of GetQuote requests to the Guest TD.

Add tdx_hcall_set_notify_intr() helper function to implement the
SetupEventNotifyInterrupt hypercall.

This will be used by the TD quote driver.

Details about the SetupEventNotifyInterrupt TDVMCALL can be found in
TDX Guest-Host Communication Interface (GHCI) Specification, sec 3.5
"TDG.VP.VMCALL<SetupEventNotifyInterrupt>".

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>
---

Change since v2:
 * Included TDVMCALL_SUCCESS case check in tdx_hcall_set_notify_intr().

 arch/x86/kernel/tdx.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index aa49c6809a0c..27e56ab0d4a2 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -29,6 +29,7 @@
 /* TDX hypercall Leaf IDs */
 #define TDVMCALL_MAP_GPA		0x10001
 #define TDVMCALL_GET_QUOTE		0x10002
+#define TDVMCALL_SETUP_NOTIFY_INTR	0x10004
 
 /* TDX Module call error codes */
 #define TDX_PAGE_ALREADY_ACCEPTED       0x8000000000000001
@@ -208,6 +209,32 @@ int tdx_hcall_get_quote(u64 data)
 }
 EXPORT_SYMBOL_GPL(tdx_hcall_get_quote);
 
+/*
+ * tdx_hcall_set_notify_intr() - Setup Event Notify Interrupt Vector.
+ *
+ * @vector        : Vector address to be used for notification.
+ *
+ * return 0 on success or failure error number.
+ */
+int tdx_hcall_set_notify_intr(u8 vector)
+{
+	u64 ret;
+
+	/* Minimum vector value allowed is 32 */
+	if (vector < 32)
+		return -EINVAL;
+
+	ret = _trace_tdx_hypercall(TDVMCALL_SETUP_NOTIFY_INTR, vector, 0, 0, 0,
+				   NULL);
+
+	if (ret == TDVMCALL_SUCCESS)
+		return 0;
+	else if (ret == TDCALL_INVALID_OPERAND)
+		return -EINVAL;
+
+	return -EIO;
+}
+
 static void tdg_get_info(void)
 {
 	u64 ret;
-- 
2.25.1