File xsa398-2.patch of Package xen.23269

# Commit 599616d70eb886b9ad0ef9d6b51693ce790504ba
# Date 2022-03-08 16:38:02 +0000
# Author Bertrand Marquis <bertrand.marquis@arm.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
xen/arm: move errata CSV2 check earlier

CSV2 availability check is done after printing to the user that
workaround 1 will be used. Move the check before to prevent saying to the
user that workaround 1 is used when it is not because it is not needed.
This will also allow to reuse install_bp_hardening_vec function for
other use cases.

Code previously returning "true", now returns "0" to conform to
enable_smccc_arch_workaround_1 returning an int and surrounding code
doing a "return 0" if workaround is not needed.

This is part of XSA-398 / CVE-2022-23960.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Julien Grall <julien@xen.org>

--- a/xen/arch/arm/cpuerrata.c
+++ b/xen/arch/arm/cpuerrata.c
@@ -102,13 +102,6 @@ install_bp_hardening_vec(const struct ar
     printk(XENLOG_INFO "CPU%u will %s on exception entry\n",
            smp_processor_id(), desc);
 
-    /*
-     * No need to install hardened vector when the processor has
-     * ID_AA64PRF0_EL1.CSV2 set.
-     */
-    if ( cpu_data[smp_processor_id()].pfr64.csv2 )
-        return true;
-
     spin_lock(&bp_lock);
 
     /*
@@ -167,6 +160,13 @@ static int enable_smccc_arch_workaround_
     if ( !entry->matches(entry) )
         return 0;
 
+    /*
+     * No need to install hardened vector when the processor has
+     * ID_AA64PRF0_EL1.CSV2 set.
+     */
+    if ( cpu_data[smp_processor_id()].pfr64.csv2 )
+        return 0;
+
     if ( smccc_ver < SMCCC_VERSION(1, 1) )
         goto warn;