[Xen-devel] [PATCH 05/16] vmx: nest: virtual vmcs layout

[Qing He <qing.he@xxxxxxxxx>]

Since physical vmcs is transparent, a customized virtual vmcs (vvmcs) is
introduced. It converts the vmcs encoding to an offset into vvmcs page.

Signed-off-by: Qing He <qing.he@xxxxxxxxx>
Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>

---

diff -r 5935027e5e70 xen/include/asm-x86/hvm/vmx/vvmcs.h
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/xen/include/asm-x86/hvm/vmx/vvmcs.h       Wed Apr 21 00:57:40 2010 +0800
@@ -0,0 +1,154 @@
+/*
+ * vvmcs.h: virtual VMCS access for nested virtualization.
+ *
+ * Copyright (c) 2010, Intel Corporation.
+ * Author: Qing He <qing.he@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+
+#include <xen/config.h>
+#include <asm/types.h>
+
+/*
+ * Virtual VMCS layout
+ *
+ * Since physical VMCS layout is unknown, a custom layout is used
+ * for virtual VMCS seen by guest. It occupies a 4k page, and the
+ * field is offset by an 9-bit offset into u64[], The offset is as
+ * follow, which means every <width, type> pair has a max of 32
+ * fields available.
+ *
+ *             9       7      5               0
+ *             --------------------------------
+ *     offset: | width | type |     index     |
+ *             --------------------------------
+ *
+ * Also, since the lower range <width=0, type={0,1}> has only one
+ * field: VPID, it is moved to a higher offset (63), and leaves the
+ * lower range to non-indexed field like VMCS revision.
+ *
+ */
+
+#define VVMCS_REVISION 0x40000001u
+
+struct vvmcs_header {
+    u32 revision;
+    u32 abort;
+};
+
+union vmcs_encoding {
+    struct {
+        u32 access_type : 1;
+        u32 index : 9;
+        u32 type : 2;
+        u32 rsv1 : 1;
+        u32 width : 2;
+        u32 rsv2 : 17;
+    };
+    u32 word;
+};
+
+enum vvmcs_encoding_width {
+    VVMCS_WIDTH_16 = 0,
+    VVMCS_WIDTH_64,
+    VVMCS_WIDTH_32,
+    VVMCS_WIDTH_NATURAL,
+};
+
+enum vvmcs_encoding_type {
+    VVMCS_TYPE_CONTROL = 0,
+    VVMCS_TYPE_RO,
+    VVMCS_TYPE_GSTATE,
+    VVMCS_TYPE_HSTATE,
+};
+
+static inline int vvmcs_offset(u32 width, u32 type, u32 index)
+{
+    int offset;
+
+    offset = (index & 0x1f) | type << 5 | width << 7;
+
+    if ( offset == 0 )    /* vpid */
+        offset = 0x3f;
+
+    return offset;
+}
+
+static inline u64 __get_vvmcs(void *vvmcs, u32 vmcs_encoding)
+{
+    union vmcs_encoding enc;
+    u64 *content = (u64 *) vvmcs;
+    int offset;
+    u64 res;
+
+    enc.word = vmcs_encoding;
+    offset = vvmcs_offset(enc.width, enc.type, enc.index);
+    res = content[offset];
+
+    switch ( enc.width ) {
+    case VVMCS_WIDTH_16:
+        res &= 0xffff;
+        break;
+    case VVMCS_WIDTH_64:
+        if ( enc.access_type )
+            res >>= 32;
+        break;
+    case VVMCS_WIDTH_32:
+        res &= 0xffffffff;
+        break;
+    case VVMCS_WIDTH_NATURAL:
+    default:
+        break;
+    }
+
+    return res;
+}
+
+static inline void __set_vvmcs(void *vvmcs, u32 vmcs_encoding, u64 val)
+{
+    union vmcs_encoding enc;
+    u64 *content = (u64 *) vvmcs;
+    int offset;
+    u64 res;
+
+    enc.word = vmcs_encoding;
+    offset = vvmcs_offset(enc.width, enc.type, enc.index);
+    res = content[offset];
+
+    switch ( enc.width ) {
+    case VVMCS_WIDTH_16:
+        res = val & 0xffff;
+        break;
+    case VVMCS_WIDTH_64:
+        if ( enc.access_type )
+        {
+            res &= 0xffffffff;
+            res |= val << 32;
+        }
+        else
+            res = val;
+        break;
+    case VVMCS_WIDTH_32:
+        res = val & 0xffffffff;
+        break;
+    case VVMCS_WIDTH_NATURAL:
+    default:
+        res = val;
+        break;
+    }
+
+    content[offset] = res;
+}

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel