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[Minios-devel] [UNIKRAFT PATCH v3 5/8] plat: Add global struct to keep x86 CPU information



Currently, all information relates to the additional registers that can
be available on x86 CPUs, and how to save and restore them.

Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
---
 plat/common/include/x86/cpu.h  | 56 +++++++++++++++++++++++++++++++---
 plat/common/x86/cpu_features.c | 37 ++++++++++++++++++++++
 plat/kvm/Makefile.uk           |  1 +
 plat/kvm/x86/setup.c           |  2 ++
 plat/linuxu/Makefile.uk        |  1 +
 plat/linuxu/setup.c            |  7 +++++
 plat/xen/Makefile.uk           |  1 +
 plat/xen/x86/setup.c           |  2 ++
 8 files changed, 102 insertions(+), 5 deletions(-)
 create mode 100644 plat/common/x86/cpu_features.c

diff --git a/plat/common/include/x86/cpu.h b/plat/common/include/x86/cpu.h
index 001e9cac..6de62dc0 100644
--- a/plat/common/include/x86/cpu.h
+++ b/plat/common/include/x86/cpu.h
@@ -31,16 +31,62 @@
 #define __PLAT_COMMON_X86_CPU_H__
 
 #include <uk/arch/types.h>
+#include <x86/cpu_defs.h>
+#include <stdint.h>
 
 void halt(void);
 void system_off(void);
 
-static inline void cpuid(__u32 leaf, __u32 *eax, __u32 *ebx,
-               __u32 *ecx, __u32 *edx)
+enum save_cmd {
+       X86_SAVE_NONE,
+       X86_SAVE_FSAVE,
+       X86_SAVE_FXSAVE,
+       X86_SAVE_XSAVE,
+       X86_SAVE_XSAVEOPT
+};
+
+struct _x86_features {
+       unsigned long extregs_size;     /* Size of the extregs area */
+       unsigned long extregs_align;    /* Alignment of the extregs area */
+       enum save_cmd save;             /* which CPU instruction to use for
+                                        * saving/restoring extregs.
+                                        */
+};
+
+extern struct _x86_features x86_cpu_features;
+
+static inline void _init_cpufeatures(void)
 {
-       asm volatile("cpuid"
-                    : "=a"(*eax), "=b"(*ebx), "=c"(*ecx), "=d"(*edx)
-                    : "0"(leaf));
+       __u32 eax, ebx, ecx, edx;
+
+       /* Why are we saving the eax register content to the eax variable with
+        * "=a(eax)", but then never use it?
+        * Because gcc otherwise will assume that the eax register still
+        * contains "1" after this asm expression. See the "Warning" note at
+        * https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#InputOperands
+        */
+       asm volatile("cpuid" : "=a"(eax), "=c"(ecx), "=d"(edx) : "a"(1)
+                       : "ebx");
+       if (ecx & X86_CPUID1_ECX_OSXSAVE) {
+               asm volatile("cpuid" : "=a"(eax), "=c"(ecx) : "a"(0xd), "c"(1)
+                               : "ebx", "edx");
+               if (eax & X86_CPUIDD1_EAX_XSAVEOPT)
+                       x86_cpu_features.save = X86_SAVE_XSAVEOPT;
+               else
+                       x86_cpu_features.save = X86_SAVE_XSAVE;
+               asm volatile("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx)
+                               : "a"(0xd), "c"(0) : "edx");
+               x86_cpu_features.extregs_size = ebx;
+               x86_cpu_features.extregs_align = 64;
+       } else if (edx & X86_CPUID1_EDX_FXSR) {
+               x86_cpu_features.save = X86_SAVE_FXSAVE;
+               x86_cpu_features.extregs_size = 512;
+               x86_cpu_features.extregs_align = 16;
+       } else {
+               x86_cpu_features.save = X86_SAVE_FSAVE;
+               x86_cpu_features.extregs_size = 108;
+               x86_cpu_features.extregs_align = 1;
+       }
 }
 
 unsigned long read_cr2(void);
diff --git a/plat/common/x86/cpu_features.c b/plat/common/x86/cpu_features.c
new file mode 100644
index 00000000..07097397
--- /dev/null
+++ b/plat/common/x86/cpu_features.c
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Florian Schmidt <florian.schmidt@xxxxxxxxx>
+ *
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation. 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.
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * 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 HOLDER 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.
+ *
+ * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
+ */
+
+#include <x86/cpu.h>
+
+struct _x86_features x86_cpu_features;
diff --git a/plat/kvm/Makefile.uk b/plat/kvm/Makefile.uk
index 72dd8a30..5fb56ee9 100644
--- a/plat/kvm/Makefile.uk
+++ b/plat/kvm/Makefile.uk
@@ -27,6 +27,7 @@ LIBKVMPLAT_CXXFLAGS            += -DKVMPLAT
 ##
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/trace.c|common
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/traps.c|common
+LIBKVMPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/cpu_features.c|common
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/cpu_native.c|common
 ifeq ($(CONFIG_HAVE_SCHED),y)
 LIBKVMPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/thread_start.S|common
diff --git a/plat/kvm/x86/setup.c b/plat/kvm/x86/setup.c
index 47a78dcf..c17a7dd5 100644
--- a/plat/kvm/x86/setup.c
+++ b/plat/kvm/x86/setup.c
@@ -27,6 +27,7 @@
  */
 
 #include <string.h>
+#include <x86/cpu.h>
 #include <x86/traps.h>
 #include <kvm/console.h>
 #include <kvm/intctrl.h>
@@ -118,6 +119,7 @@ void _libkvmplat_entry(void *arg)
 {
        struct multiboot_info *mi = (struct multiboot_info *)arg;
 
+       _init_cpufeatures();
        _libkvmplat_init_console();
        traps_init();
        intctrl_init();
diff --git a/plat/linuxu/Makefile.uk b/plat/linuxu/Makefile.uk
index e70b4b7a..2c0de76c 100644
--- a/plat/linuxu/Makefile.uk
+++ b/plat/linuxu/Makefile.uk
@@ -20,6 +20,7 @@ LIBLINUXUPLAT_ASFLAGS             += -DLINUXUPLAT
 LIBLINUXUPLAT_CFLAGS              += -DLINUXUPLAT
 LIBLINUXUPLAT_CXXFLAGS            += -DLINUXUPLAT
 
+LIBLINUXUPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/cpu_features.c|common
 LIBLINUXUPLAT_SRCS-$(CONFIG_ARCH_X86_32) += $(LIBLINUXUPLAT_BASE)/x86/entry32.S
 LIBLINUXUPLAT_SRCS-$(CONFIG_ARCH_X86_64) += $(LIBLINUXUPLAT_BASE)/x86/entry64.S
 LIBLINUXUPLAT_SRCS-$(CONFIG_ARCH_ARM_32) += $(LIBLINUXUPLAT_BASE)/arm/entry32.S
diff --git a/plat/linuxu/setup.c b/plat/linuxu/setup.c
index 5fbf54b1..c6b910fa 100644
--- a/plat/linuxu/setup.c
+++ b/plat/linuxu/setup.c
@@ -45,6 +45,9 @@
 #include <uk/plat/bootstrap.h>
 #include <uk/assert.h>
 #include <uk/errptr.h>
+#if defined __X86_64__
+#include <x86/cpu.h>
+#endif
 
 struct liblinuxuplat_opts _liblinuxuplat_opts = { 0 };
 
@@ -150,6 +153,10 @@ void _liblinuxuplat_entry(int argc, char *argv[])
        int ret;
        void *pret;
 
+#if defined __X86_64__
+       _init_cpufeatures();
+#endif
+
        /*
         * Initialize platform console
         */
diff --git a/plat/xen/Makefile.uk b/plat/xen/Makefile.uk
index 20d1e5af..38b510ad 100644
--- a/plat/xen/Makefile.uk
+++ b/plat/xen/Makefile.uk
@@ -33,6 +33,7 @@ LIBXENPLAT_SRCS-y              += 
$(UK_PLAT_COMMON_BASE)/memory.c|common
 
 LIBXENPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/trace.c|common
 LIBXENPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/traps.c|common
+LIBXENPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/cpu_features.c|common
 ifeq ($(CONFIG_HAVE_SCHED),y)
 LIBXENPLAT_SRCS-$(CONFIG_ARCH_X86_64) += 
$(UK_PLAT_COMMON_BASE)/x86/thread_start.S|common
 LIBXENPLAT_SRCS-$(CONFIG_ARCH_X86_64) += $(UK_PLAT_COMMON_BASE)/thread.c|common
diff --git a/plat/xen/x86/setup.c b/plat/xen/x86/setup.c
index a41d5cb3..60a9f9e6 100644
--- a/plat/xen/x86/setup.c
+++ b/plat/xen/x86/setup.c
@@ -74,6 +74,7 @@
 #include <uk/plat/config.h>
 #include <uk/plat/console.h>
 #include <uk/plat/bootstrap.h>
+#include <x86/cpu.h>
 
 #include <xen/xen.h>
 #include <common/console.h>
@@ -170,6 +171,7 @@ void _libxenplat_x86entry(void *start_info) __noreturn;
 void _libxenplat_x86entry(void *start_info)
 {
        _init_traps();
+       _init_cpufeatures();
        HYPERVISOR_start_info = (start_info_t *)start_info;
        _libxenplat_prepare_console(); /* enables buffering for console */
 
-- 
2.20.1


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