[PATCH 2/5] x86: Refactor microcode_update() hypercall with flags field

[Fouad Hilly <fouad.hilly@xxxxxxxxx>]

Refactor microcode_update() hypercall by adding flags field.
Introduce XENPF_microcode_update2 hypercall to handle flags field.

Signed-off-by: Fouad Hilly <fouad.hilly@xxxxxxxxx>
---
 xen/arch/x86/cpu/microcode/core.c    | 12 +++++++++---
 xen/arch/x86/include/asm/microcode.h |  2 +-
 xen/arch/x86/platform_hypercall.c    | 12 +++++++++++-
 xen/include/public/platform.h        |  8 ++++++++
 4 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 1c9f66ea8a0f..f987b2bd632d 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -40,6 +40,8 @@
 #include <asm/processor.h>
 #include <asm/setup.h>
 
+#include <public/platform.h>
+
 #include "private.h"
 
 /*
@@ -100,6 +102,8 @@ static bool ucode_in_nmi = true;
 
 bool __read_mostly opt_ucode_allow_same;
 
+bool ucode_force_flag;
+
 /* Protected by microcode_mutex */
 static struct microcode_patch *microcode_cache;
 
@@ -633,12 +637,12 @@ static long cf_check microcode_update_helper(void *data)
                                   microcode_cache);
 
         if ( result != NEW_UCODE &&
-             !(opt_ucode_allow_same && result == SAME_UCODE) )
+             !((opt_ucode_allow_same || ucode_force_flag) && result == 
SAME_UCODE) )
         {
             spin_unlock(&microcode_mutex);
             printk(XENLOG_WARNING
                    "microcode: couldn't find any newer%s revision in the 
provided blob!\n",
-                   opt_ucode_allow_same ? " (or the same)" : "");
+                   (opt_ucode_allow_same || ucode_force_flag) ? " (or the 
same)" : "");
             microcode_free_patch(patch);
             ret = -ENOENT;
 
@@ -708,11 +712,13 @@ static long cf_check microcode_update_helper(void *data)
     return ret;
 }
 
-int microcode_update(XEN_GUEST_HANDLE(const_void) buf, unsigned long len)
+int microcode_update(XEN_GUEST_HANDLE(const_void) buf, unsigned long len, 
unsigned int flags)
 {
     int ret;
     struct ucode_buf *buffer;
 
+    ucode_force_flag = (flags == XENPF_UCODE_FLAG_FORCE_SET)? 1: 0;
+
     if ( len != (uint32_t)len )
         return -E2BIG;
 
diff --git a/xen/arch/x86/include/asm/microcode.h 
b/xen/arch/x86/include/asm/microcode.h
index 8f59b20b0289..bcba356b4134 100644
--- a/xen/arch/x86/include/asm/microcode.h
+++ b/xen/arch/x86/include/asm/microcode.h
@@ -22,7 +22,7 @@ struct cpu_signature {
 DECLARE_PER_CPU(struct cpu_signature, cpu_sig);
 
 void microcode_set_module(unsigned int idx);
-int microcode_update(XEN_GUEST_HANDLE(const_void) buf, unsigned long len);
+int microcode_update(XEN_GUEST_HANDLE(const_void) buf, unsigned long len, 
unsigned int flags);
 int early_microcode_init(unsigned long *module_map,
                          const struct multiboot_info *mbi);
 int microcode_init_cache(unsigned long *module_map,
diff --git a/xen/arch/x86/platform_hypercall.c 
b/xen/arch/x86/platform_hypercall.c
index 95467b88ab64..3b29ede8b316 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -311,7 +311,17 @@ ret_t do_platform_op(
 
         guest_from_compat_handle(data, op->u.microcode.data);
 
-        ret = microcode_update(data, op->u.microcode.length);
+        ret = microcode_update(data, op->u.microcode.length, 0);
+        break;
+    }
+
+    case XENPF_microcode_update2:
+    {
+        XEN_GUEST_HANDLE(const_void) data;
+
+        guest_from_compat_handle(data, op->u.microcode.data);
+
+        ret = microcode_update(data, op->u.microcode.length, 
op->u.microcode.flags);
         break;
     }
 
diff --git a/xen/include/public/platform.h b/xen/include/public/platform.h
index 15777b541690..31e59ba3d07b 100644
--- a/xen/include/public/platform.h
+++ b/xen/include/public/platform.h
@@ -99,6 +99,10 @@ struct xenpf_microcode_update {
     /* IN variables. */
     XEN_GUEST_HANDLE(const_void) data;/* Pointer to microcode data */
     uint32_t length;                  /* Length of microcode data. */
+    uint32_t flags;                   /* Flags to be passed with ucode. */
+/* Force to skip microcode version check when set */
+#define XENPF_UCODE_FLAG_FORCE_NOT_SET 0
+#define XENPF_UCODE_FLAG_FORCE_SET     1
 };
 typedef struct xenpf_microcode_update xenpf_microcode_update_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_microcode_update_t);
@@ -624,6 +628,10 @@ struct xenpf_ucode_revision {
 typedef struct xenpf_ucode_revision xenpf_ucode_revision_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_ucode_revision_t);
 
+/* Hypercall to microcode_update with flags */
+#define XENPF_microcode_update2    66
+
+
 /*
  * ` enum neg_errnoval
  * ` HYPERVISOR_platform_op(const struct xen_platform_op*);
-- 
2.42.0