This patch is to backport the patch below from linux kernel.
commit 30ec26da9967d0d785abc24073129a34c3211777
Author: Ashok Raj <ashok....@intel.com>
Date: Wed Feb 28 11:28:43 2018 +0100
x86/microcode: Do not upload microcode if CPUs are offline
Avoid loading microcode if any of the CPUs are offline, and issue a
warning. Having different microcode revisions on the system at any time
is outright dangerous.
[ Borislav: Massage changelog. ]
Signed-off-by: Ashok Raj <ashok....@intel.com>
Signed-off-by: Borislav Petkov <b...@suse.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Tested-by: Tom Lendacky <thomas.lenda...@amd.com>
Tested-by: Ashok Raj <ashok....@intel.com>
Reviewed-by: Tom Lendacky <thomas.lenda...@amd.com>
Cc: Arjan Van De Ven <arjan.van.de....@intel.com>
Link:
http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok....@intel.com
Link: https://lkml.kernel.org/r/20180228102846.13447-5...@alien8.de
Signed-off-by: Chao Gao <chao....@intel.com>
Cc: Kevin Tian <kevin.t...@intel.com>
Cc: Jun Nakajima <jun.nakaj...@intel.com>
Cc: Ashok Raj <ashok....@intel.com>
Cc: Borislav Petkov <b...@suse.de>
Cc: Thomas Gleixner <t...@linutronix.de>
---
xen/arch/x86/microcode.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 94c1ca2..25d9112 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -346,16 +346,27 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void)
buf, unsigned long len)
if ( microcode_ops == NULL )
return -EINVAL;
+ /* cpu_online_map must not change. */
+ if ( !get_cpu_maps() )
+ return -EBUSY;
+
+ if ( num_present_cpus() != num_online_cpus() )
+ {
+ ret = -EINVAL;
+ printk("Not all CPUs online, aborting microcode update\n");
+ goto put;
+ }
+
info = xmalloc_bytes(sizeof(*info) + len);
if ( info == NULL )
- return -ENOMEM;
+ {
+ ret = -ENOMEM;
+ goto put;
+ }
ret = copy_from_guest(info->buffer, buf, len);
if ( ret != 0 )
- {
- xfree(info);
- return ret;
- }
+ goto err;
info->buffer_size = len;
info->error = 0;
@@ -364,10 +375,7 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void)
buf, unsigned long len)
{
ret = microcode_ops->start_update();
if ( ret != 0 )
- {
- xfree(info);
- return ret;
- }
+ goto err;
}
atomic_set(&info->cpu_in, 0);
@@ -393,7 +401,11 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void)
buf, unsigned long len)
watchdog_enable();
ret = info->error;
+
+ err:
xfree(info);
+ put:
+ put_cpu_maps();
return ret;
}
--
1.8.3.1
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