cherry-pick fix for setting X86_FEATURE_OSXSAVE feature

Avoids regressions where some code falsely think they cannot use some
CPU features like AVX1, e.g., ZFS.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/patches/kernel/0016-x86-fpu-Set-X86_FEATURE_OSXSAVE-feature-after-enabli.patch b/patches/kernel/0016-x86-fpu-Set-X86_FEATURE_OSXSAVE-feature-after-enabli.patch
new file mode 100644 (file)
index 0000000..c82e202
--- /dev/null
+++ b/patches/kernel/0016-x86-fpu-Set-X86_FEATURE_OSXSAVE-feature-after-enabli.patch
@@ -0,0 +1,61 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Feng Tang <feng.tang@intel.com>
+Date: Wed, 23 Aug 2023 14:57:47 +0800
+Subject: [PATCH] x86/fpu: Set X86_FEATURE_OSXSAVE feature after enabling
+ OSXSAVE in CR4
+
+0-Day found a 34.6% regression in stress-ng's 'af-alg' test case, and
+bisected it to commit b81fac906a8f ("x86/fpu: Move FPU initialization into
+arch_cpu_finalize_init()"), which optimizes the FPU init order, and moves
+the CR4_OSXSAVE enabling into a later place:
+
+   arch_cpu_finalize_init
+       identify_boot_cpu
+          identify_cpu
+              generic_identify
+                   get_cpu_cap --> setup cpu capability
+       ...
+       fpu__init_cpu
+           fpu__init_cpu_xstate
+               cr4_set_bits(X86_CR4_OSXSAVE);
+
+As the FPU is not yet initialized the CPU capability setup fails to set
+X86_FEATURE_OSXSAVE. Many security module like 'camellia_aesni_avx_x86_64'
+depend on this feature and therefore fail to load, causing the regression.
+
+Cure this by setting X86_FEATURE_OSXSAVE feature right after OSXSAVE
+enabling.
+
+[ tglx: Moved it into the actual BSP FPU initialization code and added a comment ]
+
+Fixes: b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
+Reported-by: kernel test robot <oliver.sang@intel.com>
+Signed-off-by: Feng Tang <feng.tang@intel.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: stable@vger.kernel.org
+Link: https://lore.kernel.org/lkml/202307192135.203ac24e-oliver.sang@intel.com
+Link: https://lore.kernel.org/lkml/20230823065747.92257-1-feng.tang@intel.com
+(cherry picked from commit 2c66ca3949dc701da7f4c9407f2140ae425683a5)
+Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
+---
+ arch/x86/kernel/fpu/xstate.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
+index 0bab497c9436..1afbc4866b10 100644
+--- a/arch/x86/kernel/fpu/xstate.c
++++ b/arch/x86/kernel/fpu/xstate.c
+@@ -882,6 +882,13 @@ void __init fpu__init_system_xstate(unsigned int legacy_size)
+               goto out_disable;
+       }
+ 
++      /*
++       * CPU capabilities initialization runs before FPU init. So
++       * X86_FEATURE_OSXSAVE is not set. Now that XSAVE is completely
++       * functional, set the feature bit so depending code works.
++       */
++      setup_force_cpu_cap(X86_FEATURE_OSXSAVE);
++
+       print_xstate_offset_size();
+       pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
+               fpu_kernel_cfg.max_features,