Currently it's impossible to get CPU's microcode revision after late
loading without looking into Xen logs which is not always convenient.
Leverage xenhypfs to expose struct cpu_signature in a new cpuinfo dir.
The tree structure is:
/
cpuinfo/
cpu-signature
microcode-revision
processor-flags
The most useful bit is cpu microcode revision which will get updated
after late ucode loading.
Signed-off-by: Sergey Dyasli <sergey.dya...@citrix.com>
---
xen/arch/x86/cpu/common.c | 58 +++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 5ad347534a..aa864fdbab 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -1005,3 +1005,61 @@ const struct x86_cpu_id *x86_match_cpu(const struct
x86_cpu_id table[])
}
return NULL;
}
+
+#ifdef CONFIG_HYPFS
+#include <xen/hypfs.h>
+#include <xen/guest_access.h>
+#include <asm/microcode.h>
+
+static unsigned int cpu_signature;
+static unsigned int processor_flags;
+static unsigned int ucode_revision;
+
+int cf_check hypfs_read_cpusig(
+ const struct hypfs_entry *entry, XEN_GUEST_HANDLE_PARAM(void) uaddr)
+{
+ const struct hypfs_entry_leaf *l;
+ unsigned int size = entry->funcs->getsize(entry);
+ const struct cpu_signature *sig = &per_cpu(cpu_sig,
+ cpumask_first(&cpu_online_map));
+
+ l = container_of(entry, const struct hypfs_entry_leaf, e);
+
+ cpu_signature = sig->sig;
+ processor_flags = sig->pf;
+ ucode_revision = sig->rev;
+
+ return copy_to_guest(uaddr, l->u.content, size) ? -EFAULT : 0;
+}
+
+const struct hypfs_funcs ucode_rev_funcs = {
+ .enter = hypfs_node_enter,
+ .exit = hypfs_node_exit,
+ .read = hypfs_read_cpusig,
+ .write = hypfs_write_deny,
+ .getsize = hypfs_getsize,
+ .findentry = hypfs_leaf_findentry,
+};
+
+static HYPFS_DIR_INIT(cpuinfo, "cpuinfo");
+static HYPFS_FIXEDSIZE_INIT(signature, XEN_HYPFS_TYPE_UINT, "cpu-signature",
+ cpu_signature, &ucode_rev_funcs, 0);
+static HYPFS_FIXEDSIZE_INIT(pf, XEN_HYPFS_TYPE_UINT, "processor-flags",
+ processor_flags, &ucode_rev_funcs, 0);
+static HYPFS_FIXEDSIZE_INIT(revision, XEN_HYPFS_TYPE_UINT,
"microcode-revision",
+ ucode_revision, &ucode_rev_funcs, 0);
+
+static int __init cf_check cpuinfo_init(void)
+{
+ hypfs_add_dir(&hypfs_root, &cpuinfo, true);
+ hypfs_add_leaf(&cpuinfo, &signature, true);
+
+ if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
+ hypfs_add_leaf(&cpuinfo, &pf, true);
+
+ hypfs_add_leaf(&cpuinfo, &revision, true);
+
+ return 0;
+}
+__initcall(cpuinfo_init);
+#endif /* CONFIG_HYPFS */
--
2.17.1
