On January 22, 2024 8:32:22 AM PST, Dave Hansen [off-list ref] wrote:

On 1/9/24 00:40, Alexey Makhalov wrote:

quoted

+#ifdef CONFIG_INTEL_TDX_GUEST
+unsigned long vmware_tdx_hypercall(unsigned long cmd,
+				   struct tdx_module_args *args)
+{
+	if (!hypervisor_is_type(X86_HYPER_VMWARE))
+		return ULONG_MAX;
+
+	if (cmd & ~VMWARE_CMD_MASK) {
+		pr_warn_once("Out of range command %lx\n", cmd);
+		return ULONG_MAX;
+	}
+
+	args->r10 = VMWARE_TDX_VENDOR_LEAF;
+	args->r11 = VMWARE_TDX_HCALL_FUNC;
+	args->r12 = VMWARE_HYPERVISOR_MAGIC;
+	args->r13 = cmd;
+	args->r15 = 0; /* CPL */
+
+	__tdx_hypercall(args);
+
+	return args->r12;
+}
+EXPORT_SYMBOL_GPL(vmware_tdx_hypercall);
+#endif

This is the kind of wrapper that I was hoping for.  Thanks.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>

I'm slightly confused by this TBH.

Why are the arguments passed in as a structure, which is modified by the wrapper to boot? This is analogous to a system call interface.

Furthermore, this is an out-of-line function; it should never be called with !X86_HYPER_VMWARE or you are introducing overhead for other hypervisors; I believe a pr_warn_once() is in order at least, just as you have for the out-of-range test.