diff --git a/Documentation/arch/x86/xstate.rst b/Documentation/arch/x86/xstate.rst
index 5cec7fb558d60346d2b55039c2dd7882575ea3aa..ae5c69e48b115180ab25f96ee67ea100dfe1b664 100644
--- a/Documentation/arch/x86/xstate.rst
+++ b/Documentation/arch/x86/xstate.rst
@@ -11,6 +11,22 @@ are enabled by XCR0 as well, but the first use of related instruction is
 trapped by the kernel because by default the required large XSTATE buffers
 are not allocated automatically.
 
+The purpose for dynamic features
+--------------------------------
+
+Legacy userspace libraries often have hard-coded, static sizes for
+alternate signal stacks, often using MINSIGSTKSZ which is typically 2KB.
+That stack must be able to store at *least* the signal frame that the
+kernel sets up before jumping into the signal handler. That signal frame
+must include an XSAVE buffer defined by the CPU.
+
+However, that means that the size of signal stacks is dynamic, not static,
+because different CPUs have differently-sized XSAVE buffers. A compiled-in
+size of 2KB with existing applications is too small for new CPU features
+like AMX. Instead of universally requiring larger stack, with the dynamic
+enabling, the kernel can enforce userspace applications to have
+properly-sized altstacks.
+
 Using dynamically enabled XSTATE features in user space applications
 --------------------------------------------------------------------
 
@@ -64,6 +80,61 @@ the handler allocates a larger xstate buffer for the task so the large
 state can be context switched. In the unlikely cases that the allocation
 fails, the kernel sends SIGSEGV.
 
+AMX TILE_DATA enabling example
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Below is the example of how userspace applications enable
+TILE_DATA dynamically:
+
+  1. The application first needs to query the kernel for AMX
+     support::
+
+        #include <asm/prctl.h>
+        #include <sys/syscall.h>
+        #include <stdio.h>
+        #include <unistd.h>
+
+        #ifndef ARCH_GET_XCOMP_SUPP
+        #define ARCH_GET_XCOMP_SUPP  0x1021
+        #endif
+
+        #ifndef ARCH_XCOMP_TILECFG
+        #define ARCH_XCOMP_TILECFG   17
+        #endif
+
+        #ifndef ARCH_XCOMP_TILEDATA
+        #define ARCH_XCOMP_TILEDATA  18
+        #endif
+
+        #define MASK_XCOMP_TILE      ((1 << ARCH_XCOMP_TILECFG) | \
+                                      (1 << ARCH_XCOMP_TILEDATA))
+
+        unsigned long features;
+        long rc;
+
+        ...
+
+        rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_SUPP, &features);
+
+        if (!rc && (features & MASK_XCOMP_TILE) == MASK_XCOMP_TILE)
+            printf("AMX is available.\n");
+
+  2. After that, determining support for AMX, an application must
+     explicitly ask permission to use it::
+
+        #ifndef ARCH_REQ_XCOMP_PERM
+        #define ARCH_REQ_XCOMP_PERM  0x1023
+        #endif
+
+        ...
+
+        rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, ARCH_XCOMP_TILEDATA);
+
+        if (!rc)
+            printf("AMX is ready for use.\n");
+
+Note this example does not include the sigaltstack preparation.
+
 Dynamic features in signal frames
 ---------------------------------
 
@@ -72,3 +143,32 @@ entry if the feature is in its initial configuration.  This differs from
 non-dynamic features which are always written regardless of their
 configuration.  Signal handlers can examine the XSAVE buffer's XSTATE_BV
 field to determine if a features was written.
+
+Dynamic features for virtual machines
+-------------------------------------
+
+The permission for the guest state component needs to be managed separately
+from the host, as they are exclusive to each other. A coupled of options
+are extended to control the guest permission:
+
+-ARCH_GET_XCOMP_GUEST_PERM
+
+ arch_prctl(ARCH_GET_XCOMP_GUEST_PERM, &features);
+
+ ARCH_GET_XCOMP_GUEST_PERM is a variant of ARCH_GET_XCOMP_PERM. So it
+ provides the same semantics and functionality but for the guest
+ components.
+
+-ARCH_REQ_XCOMP_GUEST_PERM
+
+ arch_prctl(ARCH_REQ_XCOMP_GUEST_PERM, feature_nr);
+
+ ARCH_REQ_XCOMP_GUEST_PERM is a variant of ARCH_REQ_XCOMP_PERM. It has the
+ same semantics for the guest permission. While providing a similar
+ functionality, this comes with a constraint. Permission is frozen when the
+ first VCPU is created. Any attempt to change permission after that point
+ is going to be rejected. So, the permission has to be requested before the
+ first VCPU creation.
+
+Note that some VMMs may have already established a set of supported state
+components. These options are not presumed to support any particular VMM.
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 500b96e71f1868dd097a2a796c8da89b5f85bed3..f298c778f856e9f77a8979120b4e0ac6451ec0ee 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -16,6 +16,9 @@
 #define ARCH_GET_XCOMP_GUEST_PERM	0x1024
 #define ARCH_REQ_XCOMP_GUEST_PERM	0x1025
 
+#define ARCH_XCOMP_TILECFG		17
+#define ARCH_XCOMP_TILEDATA		18
+
 #define ARCH_MAP_VDSO_X32		0x2001
 #define ARCH_MAP_VDSO_32		0x2002
 #define ARCH_MAP_VDSO_64		0x2003