Merge: x86/tdx: Fix "in-kernel MMIO" check

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6616

JIRA: https://issues.redhat.com/browse/RHEL-63318
CVE: CVE-2024-47727

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Approved-by: Maxim Levitsky <mlevitsk@redhat.com>
Approved-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Approved-by: Paolo Bonzini <bonzini@gnu.org>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

arch/x86/coco/tdx/tdx.c

@@ -16,6 +16,7 @@
 #include <asm/insn-eval.h>
 #include <asm/pgtable.h>
 #include <asm/set_memory.h>
+#include <asm/traps.h>
 
 /* MMIO direction */
 #define EPT_READ	0
@@ -532,6 +533,11 @@ static int handle_mmio(struct pt_regs *regs, struct ve_info *ve)
 			return -EINVAL;
 	}
 
+	if (!fault_in_kernel_space(ve->gla)) {
+		WARN_ONCE(1, "Access to userspace address is not supported");
+		return -EINVAL;
+	}
+
 	/*
 	 * Reject EPT violation #VEs that split pages.
 	 *