Memory-Type Range Registers (MTRR) support

arch/x86/mtrr.c

@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2022 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <mtrr.h>
+#include <pagetable.h>
+
+mtrr_cap_t mtrr_read_cap(void) {
+    mtrr_cap_t c;
+    c.reg = rdmsr(MSR_MTRR_CAP);
+    return c;
+}
+
+mtrr_def_type_t mtrr_read_def_type(void) {
+    mtrr_def_type_t t;
+    t.reg = rdmsr(MSR_MTRR_DEF_TYPE);
+    return t;
+}
+
+bool mtrr_set_phys_base(mtrr_base_t base, uint8_t reg) {
+    mtrr_cap_t cap = mtrr_read_cap();
+    if (reg < cap.vcnt) {
+        wrmsr(MSR_MTRR_PHYS_BASE(reg), base.reg);
+        return true;
+    }
+    return false;
+}
+
+bool mtrr_set_phys_mask(mtrr_mask_t mask, uint8_t reg) {
+    mtrr_cap_t cap = mtrr_read_cap();
+    if (reg < cap.vcnt) {
+        wrmsr(MSR_MTRR_PHYS_MASK(reg), mask.reg);
+        return true;
+    }
+    return false;
+}

include/arch/x86/processor.h

@@ -93,6 +93,24 @@
  */
 #define MSR_PAT 0x277
 
+#define MSR_MTRR_FIX_64K_00000 0x250
+#define MSR_MTRR_FIX_16K_80000 0x258
+#define MSR_MTRR_FIX_16K_A0000 0x259
+#define MSR_MTRR_FIX_4K_C0000  0x268
+#define MSR_MTRR_FIX_4K_C8000  0x269
+#define MSR_MTRR_FIX_4K_D0000  0x26A
+#define MSR_MTRR_FIX_4K_D8000  0x26B
+#define MSR_MTRR_FIX_4K_E0000  0x26C
+#define MSR_MTRR_FIX_4K_E8000  0x26D
+#define MSR_MTRR_FIX_4K_F0000  0x26E
+#define MSR_MTRR_FIX_4K_F8000  0x26F
+
+#define MSR_MTRR_CAP      0x2FF
+#define MSR_MTRR_DEF_TYPE 0x2FF
+
+#define MSR_MTRR_PHYS_BASE(n) (0x200 + (n * 2))
+#define MSR_MTRR_PHYS_MASK(n) (0x201 + (n * 2))
+
 #define MSR_APIC_BASE 0x0000001B
 
 #define MSR_EFER   0xc0000080      /* Extended Feature Enable Register */

include/mtrr.h

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2022 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef KTF_MTRR_H
+#define KTF_MTRR_H
+
+#include <ktf.h>
+
+enum mtrr_memory_type {
+    MTRR_UC = 0, /* Uncacheable */
+    MTRR_WC = 1, /* Write Combining */
+    MTRR_WT = 4, /* Write Through */
+    MTRR_WP,     /* Write Protected */
+    MTRR_WB,     /* Write Back */
+};
+typedef enum mtrr_memory_type mtrr_memory_type_t;
+
+union mtrr_cap {
+    struct {
+        /* clang-format off */
+        uint64_t vcnt : 8,
+		 fix : 1,
+		 _rsvd : 1,
+		 wc : 1,
+		 _rsvd2 : 53;
+        /* clang-format on */
+    } __packed;
+    uint64_t reg;
+};
+typedef union mtrr_cap mtrr_cap_t;
+
+union mtrr_def_type {
+    struct {
+        /* clang-format off */
+        uint64_t type : 8,
+		 _rsvd : 2,
+		 fe : 1,
+		 e : 1,
+		 _rsvd2 : 52;
+        /* clang-format on */
+    } __packed;
+    uint64_t reg;
+};
+typedef union mtrr_def_type mtrr_def_type_t;
+
+union mtrr_base {
+    struct {
+        /* clang-format off */
+        uint64_t type : 8,
+		 _rsvd : 4,
+		 phys_base : 40,
+		 _rsvd2 : 12;
+        /* clang-format on */
+    } __packed;
+    uint64_t reg;
+};
+typedef union mtrr_base mtrr_base_t;
+
+union mtrr_mask {
+    struct {
+        /* clang-format off */
+        uint64_t _rsvd : 10,
+		 valid : 1,
+		 phys_base : 40,
+		 _rsvd2 : 13;
+        /* clang-format on */
+    } __packed;
+    uint64_t reg;
+};
+typedef union mtrr_mask mtrr_mask_t;
+
+extern mtrr_cap_t mtrr_read_cap(void);
+extern mtrr_def_type_t mtrr_read_def_type(void);
+extern bool mtrr_set_phys_base(mtrr_base_t base, uint8_t reg);
+extern bool mtrr_set_phys_mask(mtrr_mask_t mask, uint8_t reg);
+
+#endif /* KTF_MTRR_H */