x86/ucode: Extend AMD digest checks to cover Zen5 CPUs

AMD have updated the SB-7033 advisory to include Zen5 CPUs.  Extend the digest
check to cover Zen5 too.

In practice, cover everything until further notice.

Observant readers may be wondering where the update to the digest list is.  At
the time of writing, no Zen5 patches are available via a verifiable channel.

Link: https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7033.html
Fixes: 630e8875ab ("x86/ucode: Perform extra SHA2 checks on AMD Fam17h/19h microcode")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit b63951467e)

x86/ucode: Extend warning about disabling digest check too

This was missed by accident.

Fixes: b63951467e ("x86/ucode: Extend AMD digest checks to cover Zen5 CPUs")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 59bb316ea8)

xen/arch/x86/cpu/microcode/amd.c

@@ -118,8 +118,12 @@ static bool check_digest(const struct container_microcode *mc)
     const struct patch_digest *pd;
     uint8_t digest[SHA2_256_DIGEST_SIZE];
 
-    /* Only Fam17h/19h are known to need extra checks.  Skip other families. */
-    if ( boot_cpu_data.x86 < 0x17 || boot_cpu_data.x86 > 0x19 ||
+    /*
+     * Zen1 thru Zen5 CPUs are known to use a weak signature algorithm on
+     * microcode updates.  Mitigate by checking the digest of the patch
+     * against a list of known provenance.
+     */
+    if ( boot_cpu_data.x86 < 0x17 ||
          !opt_digest_check )
         return true;
 
@@ -513,8 +517,7 @@ static const struct microcode_ops __initconst_cf_clobber amd_ucode_ops = {
 
 void __init ucode_probe_amd(struct microcode_ops *ops)
 {
-    if ( !opt_digest_check &&
-         boot_cpu_data.x86 >= 0x17 && boot_cpu_data.x86 <= 0x19 )
+    if ( !opt_digest_check && boot_cpu_data.x86 >= 0x17 )
     {
         printk(XENLOG_WARNING
                "Microcode patch additional digest checks disabled");