patches/kernel/0293-x86-microcode-Extend-post-microcode-reload-to-suppor.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Tom Lendacky <thomas.lendacky@amd.com>
   3 Date: Wed, 20 Dec 2017 10:55:47 +0000
   4 Subject: [PATCH] x86/microcode: Extend post microcode reload to support IBPB
   5  feature
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 CVE-2017-5753
  11 CVE-2017-5715
  12
  13 Add an IBPB feature check to the speculative control update check after
  14 a microcode reload.
  15
  16 Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
  17 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  18 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  19 (cherry picked from commit 099878acd3738271fb2ade01f4649b1ed2fb72d5)
  20 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  21 ---
  22  arch/x86/kernel/cpu/microcode/core.c | 7 +++++++
  23  1 file changed, 7 insertions(+)
  24
  25 diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
  26 index 55086921d29e..638c08350d65 100644
  27 --- a/arch/x86/kernel/cpu/microcode/core.c
  28 +++ b/arch/x86/kernel/cpu/microcode/core.c
  29 @@ -546,6 +546,13 @@ static ssize_t reload_store(struct device *dev,
  30                 if (ibpb_inuse)
  31                         sysctl_ibpb_enabled = 1;
  32                 mutex_unlock(&spec_ctrl_mutex);
  33 +       } else if (boot_cpu_has(X86_FEATURE_IBPB)) {
  34 +               printk_once(KERN_INFO "FEATURE IBPB Present\n");
  35 +               mutex_lock(&spec_ctrl_mutex);
  36 +               set_ibpb_supported();
  37 +               if (ibpb_inuse)
  38 +                       sysctl_ibpb_enabled = 1;
  39 +               mutex_unlock(&spec_ctrl_mutex);
  40         }
  41
  42         mutex_unlock(&microcode_mutex);
  43 --
  44 2.14.2
  45