ANDROID: KVM: arm64: wait_for_initramfs for pKVM module loading procfs

Of course, the initramfs needs to be ready before procfs can be
mounted... in the initramfs. While at it, only mount if a pKVM module
must be loaded and only print a warning in case of failure.

Bug: 357781595
Bug: 301483379
Bug: 331152809
Change-Id: Ie56bd26d4575f69cb1f06ba6317a098649f6da44
Reported-by: Mankyum Kim <mankyum.kim@samsung-slsi.corp-partner.google.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

arch/arm64/kvm/pkvm.c

@@ -5,6 +5,7 @@
  */
 
 #include <linux/init.h>
+#include <linux/initrd.h>
 #include <linux/interval_tree_generic.h>
 #include <linux/io.h>
 #include <linux/iommu.h>
@@ -30,6 +31,9 @@
 
 #include <kvm/device.h>
 
+#include <linux/init_syscalls.h>
+#include <uapi/linux/mount.h>
+
 #include "hyp_constants.h"
 #include "hyp_trace.h"
 
@@ -870,6 +874,7 @@ static int __init __pkvm_request_early_module(char *module_name,
 		"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
 		NULL
 	};
+	static bool proc;
 	char **argv;
 	int idx = 0;
 
@@ -901,6 +906,15 @@ static int __init __pkvm_request_early_module(char *module_name,
 	/* Even with CONFIG_STATIC_USERMODEHELPER we really want this path */
 	info->path = modprobe_path;
 
+	if (!proc) {
+		wait_for_initramfs();
+		if (init_mount("proc", "/proc", "proc",
+			       MS_SILENT | MS_NOEXEC | MS_NOSUID, NULL))
+			pr_warn("Couldn't mount /proc, pKVM module parameters will be ignored\n");
+
+		proc = true;
+	}
+
 	return call_usermodehelper_exec(info, UMH_WAIT_PROC | UMH_KILLABLE);
 err:
 	kfree(argv);