x86/fpu/amx: Enable the AMX feature in 64-bit mode

Add the AMX state components in XFEATURE_MASK_USER_SUPPORTED and the
TILE_DATA component to the dynamic states and update the permission check
table accordingly.

This is only effective on 64 bit kernels as for 32bit kernels
XFEATURE_MASK_TILE is defined as 0.

TILE_DATA is caller-saved state and the only dynamic state. Add build time
sanity check to ensure the assumption that every dynamic feature is caller-
saved.

Make AMX state depend on XFD as it is dynamic feature.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211021225527.10184-24-chang.seok.bae@intel.com

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 10adf13..0f8b90a 100644 (file)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -35,7 +35,8 @@
                                      XFEATURE_MASK_Hi16_ZMM     | \
                                      XFEATURE_MASK_PKRU | \
                                      XFEATURE_MASK_BNDREGS | \
-                                     XFEATURE_MASK_BNDCSR)
+                                     XFEATURE_MASK_BNDCSR | \
+                                     XFEATURE_MASK_XTILE)
 
 /*
  * Features which are restored when returning to user space.
@@ -46,7 +47,7 @@
        (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
 
 /* Features which are dynamically enabled for a process on request */
-#define XFEATURE_MASK_USER_DYNAMIC     0ULL
+#define XFEATURE_MASK_USER_DYNAMIC     XFEATURE_MASK_XTILE_DATA
 
 /* All currently supported supervisor features */
 #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index d9ead9c..cb2fdd1 100644 (file)
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -76,6 +76,7 @@ static const struct cpuid_dep cpuid_deps[] = {
        { X86_FEATURE_SGX1,                     X86_FEATURE_SGX       },
        { X86_FEATURE_SGX2,                     X86_FEATURE_SGX1      },
        { X86_FEATURE_XFD,                      X86_FEATURE_XSAVES    },
+       { X86_FEATURE_AMX_TILE,                 X86_FEATURE_XFD       },
        {}
 };
 

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 12ca174..290836d 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -495,6 +495,12 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags)
        }
 
        /*
+        * If a new feature is added, ensure all dynamic features are
+        * caller-saved from here!
+        */
+       BUILD_BUG_ON(XFEATURE_MASK_USER_DYNAMIC != XFEATURE_MASK_XTILE_DATA);
+
+       /*
         * Save the default portion of the current FPU state into the
         * clone. Assume all dynamic features to be defined as caller-
         * saved, which enables skipping both the expansion of fpstate

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 987a07b..d288294 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -404,7 +404,8 @@ static __init void os_xrstor_booting(struct xregs_state *xstate)
         XFEATURE_MASK_PKRU |                   \
         XFEATURE_MASK_BNDREGS |                \
         XFEATURE_MASK_BNDCSR |                 \
-        XFEATURE_MASK_PASID)
+        XFEATURE_MASK_PASID |                  \
+        XFEATURE_MASK_XTILE)
 
 /*
  * setup the xstate image representing the init state
@@ -1636,7 +1637,7 @@ static int __xstate_request_perm(u64 permitted, u64 requested)
  * Permissions array to map facilities with more than one component
  */
 static const u64 xstate_prctl_req[XFEATURE_MAX] = {
-       /* [XFEATURE_XTILE_DATA] = XFEATURE_MASK_XTILE, */
+       [XFEATURE_XTILE_DATA] = XFEATURE_MASK_XTILE_DATA,
 };
 
 static int xstate_request_perm(unsigned long idx)