Simple patches for Linux as a guest OS in a plex86 VM (please consider)

[Kevin Lawton <kevinlawton2001@yahoo.com>]

[-- Attachment #1: Type: text/plain, Size: 946 bytes --]

Hello all,

I'm working on running Linux as a guest OS inside a
lightweight cut-down plex86 environment.  My goal is to
run a stock Linux kernel, which can be slimmed down to
the essentials via kernel configuration, since a guest
OS doesn't need to drive much hardware.

For this, there's a few critical but simple diffs to
macro'ize the use of the PUSHF and POPF instructions,
due to broken semantics of running stuff using
PVI (protected mode virtual interrupts).  The rest of
the stuff I believe can be monitored effectively by
the VM monitor.

Would you please consider integrating these diffs before 2.6?
There's only one new header file, and macro substitution for
a few cases where these instructions are used.  For a normal
compile, there are zero logic changes.  Just 1:1 macros.

Thanks much,
-Kevin Lawton

__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com

[-- Attachment #2: linux-2.5.59-hal.diffs --]
[-- Type: application/octet-stream, Size: 14344 bytes --]

diff -urN linux-2.5.59/arch/i386/Kconfig linux-2.5.59-hal/arch/i386/Kconfig
--- linux-2.5.59/arch/i386/Kconfig	Wed Jan 22 12:25:59 2003
+++ linux-2.5.59-hal/arch/i386/Kconfig	Tue Jan 21 17:23:41 2003
@@ -1661,3 +1661,18 @@
 	bool
 	depends on SMP
 	default y
+
+menu "Hardware Abstraction Layer"
+
+config X86_HAL
+	bool "Compile for HAL (experimental)"
+	depends on !HIGHMEM && !SMP && !M486 && !M386 && !X86_UP_APIC && !X86_UP_IOAPIC
+	help
+    Say Y here _only_ if you are compiling Linux to run inside an
+    experimental Hardware Abstraction Layer.  Say N here unless
+    you absolutely know what this is for.  This will break Linux
+    running on a real machine for sure.  This option has the
+    following configuration constraints: Pentium or higher,
+    uniprocessor mode, no apic support.
+
+endmenu
diff -urN linux-2.5.59/arch/i386/kernel/acpi_wakeup.S linux-2.5.59-hal/arch/i386/kernel/acpi_wakeup.S
--- linux-2.5.59/arch/i386/kernel/acpi_wakeup.S	Tue Jan 14 00:58:23 2003
+++ linux-2.5.59-hal/arch/i386/kernel/acpi_wakeup.S	Tue Jan 21 18:35:48 2003
@@ -2,6 +2,7 @@
 #include <linux/linkage.h>
 #include <asm/segment.h>
 #include <asm/page.h>
+#include <asm/if.h>
 
 #
 # wakeup_code runs in real mode, and at unknown address (determined at run-time).
@@ -35,7 +36,7 @@
 	movw	$0x0e00 + 'S', %fs:(0x12)
 
 	pushl	$0						# Kill any dangerous flags
-	popfl
+	POPFL
 
 	movl	real_magic - wakeup_code, %eax
 	cmpl	$0x12345678, %eax
@@ -283,7 +284,7 @@
 	movl %ebp, saved_context_ebp
 	movl %esi, saved_context_esi
 	movl %edi, saved_context_edi
-	pushfl ; popl saved_context_eflags
+	PUSHFL ; popl saved_context_eflags
 
 	movl $.L1432,saved_eip
 	movl %esp,saved_esp
@@ -309,7 +310,7 @@
 	movl saved_context_esi, %esi
 	movl saved_context_edi, %edi
 	call restore_processor_state
-	pushl saved_context_eflags ; popfl
+	pushl saved_context_eflags ; POPFL
 	ret
 
 ALIGN
diff -urN linux-2.5.59/arch/i386/kernel/cpu/common.c linux-2.5.59-hal/arch/i386/kernel/cpu/common.c
--- linux-2.5.59/arch/i386/kernel/cpu/common.c	Tue Jan 14 00:58:04 2003
+++ linux-2.5.59-hal/arch/i386/kernel/cpu/common.c	Wed Jan 22 02:01:26 2003
@@ -7,6 +7,7 @@
 #include <asm/msr.h>
 #include <asm/io.h>
 #include <asm/mmu_context.h>
+#include <asm/if.h>
 
 #include "cpu.h"
 
@@ -170,16 +171,16 @@
 {
 	u32 f1, f2;
 
-	asm("pushfl\n\t"
-	    "pushfl\n\t"
+	asm( PUSHFL
+	     PUSHFL
 	    "popl %0\n\t"
 	    "movl %0,%1\n\t"
 	    "xorl %2,%0\n\t"
 	    "pushl %0\n\t"
-	    "popfl\n\t"
-	    "pushfl\n\t"
+	     POPFL
+	     PUSHFL
 	    "popl %0\n\t"
-	    "popfl\n\t"
+	     POPFL
 	    : "=&r" (f1), "=&r" (f2)
 	    : "ir" (flag));
 
@@ -473,7 +474,7 @@
 	/*
 	 * Delete NT
 	 */
-	__asm__("pushfl ; andl $0xffffbfff,(%esp) ; popfl");
+	__asm__(PUSHFL " ; andl $0xffffbfff,(%%esp) ; " POPFL : );
 
 	/*
 	 * Set up and load the per-CPU TSS and LDT
diff -urN linux-2.5.59/arch/i386/kernel/entry.S linux-2.5.59-hal/arch/i386/kernel/entry.S
--- linux-2.5.59/arch/i386/kernel/entry.S	Wed Jan 22 12:25:59 2003
+++ linux-2.5.59-hal/arch/i386/kernel/entry.S	Tue Jan 21 18:36:16 2003
@@ -48,6 +48,7 @@
 #include <asm/segment.h>
 #include <asm/smp.h>
 #include <asm/page.h>
+#include <asm/if.h>
 #include "irq_vectors.h"
 
 EBX		= 0x00
@@ -141,7 +142,7 @@
 
 
 ENTRY(lcall7)
-	pushfl			# We get a different stack layout with call
+	PUSHFL			# We get a different stack layout with call
 				# gates, which has to be cleaned up later..
 	pushl %eax
 	SAVE_ALL
@@ -163,7 +164,7 @@
 	jmp resume_userspace
 
 ENTRY(lcall27)
-	pushfl			# We get a different stack layout with call
+	PUSHFL			# We get a different stack layout with call
 				# gates, which has to be cleaned up later..
 	pushl %eax
 	SAVE_ALL
@@ -233,7 +234,7 @@
 	sti
 	pushl $(__USER_DS)
 	pushl %ebp
-	pushfl
+	PUSHFL
 	pushl $(__USER_CS)
 	pushl $SYSENTER_RETURN
 
diff -urN linux-2.5.59/arch/i386/kernel/head.S linux-2.5.59-hal/arch/i386/kernel/head.S
--- linux-2.5.59/arch/i386/kernel/head.S	Tue Jan 14 00:58:06 2003
+++ linux-2.5.59-hal/arch/i386/kernel/head.S	Tue Jan 21 18:35:07 2003
@@ -16,6 +16,7 @@
 #include <asm/pgtable.h>
 #include <asm/desc.h>
 #include <asm/cache.h>
+#include <asm/if.h>
 
 #define OLD_CL_MAGIC_ADDR	0x90020
 #define OLD_CL_MAGIC		0xA33F
@@ -111,7 +112,7 @@
 	orw  %bx,%bx
 	jz  1f				/* Initial CPU cleans BSS */
 	pushl $0
-	popfl
+	POPFL
 	jmp checkCPUtype
 1:
 #endif CONFIG_SMP
@@ -138,7 +139,7 @@
  * XXX - best to initialize before switching to protected mode.
  */
 	pushl $0
-	popfl
+	POPFL
 /*
  * Copy bootup parameters out of the way. First 2kB of
  * _empty_zero_page is for boot parameters, second 2kB
@@ -180,17 +181,17 @@
  */
 
 	movb $3,X86		# at least 386
-	pushfl			# push EFLAGS
+	PUSHFL			# push EFLAGS
 	popl %eax		# get EFLAGS
 	movl %eax,%ecx		# save original EFLAGS
 	xorl $0x240000,%eax	# flip AC and ID bits in EFLAGS
 	pushl %eax		# copy to EFLAGS
-	popfl			# set EFLAGS
-	pushfl			# get new EFLAGS
+	POPFL			# set EFLAGS
+	PUSHFL			# get new EFLAGS
 	popl %eax		# put it in eax
 	xorl %ecx,%eax		# change in flags
 	pushl %ecx		# restore original EFLAGS
-	popfl
+	POPFL
 	testl $0x40000,%eax	# check if AC bit changed
 	je is386
 
diff -urN linux-2.5.59/arch/i386/kernel/suspend_asm.S linux-2.5.59-hal/arch/i386/kernel/suspend_asm.S
--- linux-2.5.59/arch/i386/kernel/suspend_asm.S	Tue Jan 14 00:58:33 2003
+++ linux-2.5.59-hal/arch/i386/kernel/suspend_asm.S	Tue Jan 21 18:36:31 2003
@@ -5,6 +5,7 @@
 #include <linux/linkage.h>
 #include <asm/segment.h>
 #include <asm/page.h>
+#include <asm/if.h>
 
 ENTRY(do_magic)
 	pushl %ebx
@@ -21,7 +22,7 @@
 	movl %ebp, saved_context_ebp
 	movl %esi, saved_context_esi
 	movl %edi, saved_context_edi
-	pushfl ; popl saved_context_eflags
+	PUSHFL ; popl saved_context_eflags
 
 	call do_magic_suspend_2
 	jmp .L1449
@@ -77,7 +78,7 @@
 	movl saved_context_esi, %esi
 	movl saved_context_edi, %edi
 	call restore_processor_state
-	pushl saved_context_eflags ; popfl
+	pushl saved_context_eflags ; POPFL
 	call do_magic_resume_2
 .L1449:
 	popl %ebx
@@ -89,4 +90,4 @@
 loop2:
        .quad 0
        .previous
-	
\ No newline at end of file
+	
diff -urN linux-2.5.59/drivers/hotplug/cpqphp_nvram.c linux-2.5.59-hal/drivers/hotplug/cpqphp_nvram.c
--- linux-2.5.59/drivers/hotplug/cpqphp_nvram.c	Tue Jan 14 00:59:15 2003
+++ linux-2.5.59-hal/drivers/hotplug/cpqphp_nvram.c	Tue Jan 21 18:25:57 2003
@@ -37,6 +37,7 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <asm/uaccess.h>
+#include <asm/if.h>
 #include "cpqphp.h"
 #include "cpqphp_nvram.h"
 
@@ -179,7 +180,7 @@
 	__asm__ (
 		"xorl   %%ebx,%%ebx\n" \
 		"xorl    %%edx,%%edx\n" \
-		"pushf\n" \
+		 PUSHFL   \
 		"push %%cs\n" \
 		"cli\n" \
 		"call *%6\n"
diff -urN linux-2.5.59/drivers/pnp/pnpbios/core.c linux-2.5.59-hal/drivers/pnp/pnpbios/core.c
--- linux-2.5.59/drivers/pnp/pnpbios/core.c	Tue Jan 14 00:58:04 2003
+++ linux-2.5.59-hal/drivers/pnp/pnpbios/core.c	Tue Jan 21 18:31:26 2003
@@ -54,6 +54,7 @@
 #include <linux/spinlock.h>
 #include <asm/system.h>
 #include <asm/byteorder.h>
+#include <asm/if.h>
 
 
 /*
@@ -185,11 +186,11 @@
 		"pushl %%es\n\t"
 		"pushl %%fs\n\t"
 		"pushl %%gs\n\t"
-		"pushfl\n\t"
+		 PUSHFL
 		"movl %%esp, pnp_bios_fault_esp\n\t"
 		"movl $1f, pnp_bios_fault_eip\n\t"
 		"lcall %5,%6\n\t"
-		"1:popfl\n\t"
+		"1:" POPFL
 		"popl %%gs\n\t"
 		"popl %%fs\n\t"
 		"popl %%es\n\t"
diff -urN linux-2.5.59/include/asm-i386/if.h linux-2.5.59-hal/include/asm-i386/if.h
--- linux-2.5.59/include/asm-i386/if.h	Wed Dec 31 19:00:00 1969
+++ linux-2.5.59-hal/include/asm-i386/if.h	Wed Jan 22 11:26:59 2003
@@ -0,0 +1,139 @@
+/*
+ *	Routines to manipulate the interrupt flag (EFLAGS.IF).  Abstracting
+ *	them, makes it easier to compile for a hardware abstraction layer (HAL).
+ *
+ *	(c) 2003 Kevin P. Lawton <kevinlawton2001@yahoo.com>
+ */
+
+#ifndef _LINUX_ASM_IF_H_
+#define _LINUX_ASM_IF_H_
+
+
+#ifndef CONFIG_X86_HAL
+
+/* For a standard compile, just use the native instructions. */
+
+#ifdef __ASSEMBLY__           /* For *.S assembly. */
+#define STI    sti
+#define CLI    cli
+#define PUSHFL pushfl
+#define POPFL  popfl
+#else                         /* For *.C assembly. */
+#define STI    "sti    \n\t"
+#define CLI    "cli    \n\t"
+#define PUSHFL "pushfl \n\t"
+#define POPFL  "popfl  \n\t"
+#endif
+
+
+#else   /* CONFIG_X86_HAL */
+
+/* For a HAL (Hardware Abstraction Layer) compile, the kernel is executed
+ * at PL=3 using PVI (Protected mode Virtual Interrupts), which are the
+ * analog to VME for v86 code.  For some reason, The Creators stopped short of
+ * implementing proper IF handling for PUSHF/POPF for PVI, but STI/CLI are
+ * fine.  So we have to complete the PVI semantics using the following
+ * sequences.
+ */
+
+/* cli/sti both work in PVI */
+#ifdef __ASSEMBLY__           /* For *.S assembly. */
+#define STI    sti
+#define CLI    cli
+#else                         /* For *.C assembly. */
+#define STI    "sti    \n\t"
+#define CLI    "cli    \n\t"
+#endif
+
+
+/* PUSHFL:
+ * When execution is monitored using PVI (Protected mode Virtual Interrupts),
+ * we have to complete the PVI semantics of the PUSHFL instruction, as
+ * per behaviour of VME.
+ *
+ *                        b19           b9
+ * CPU   image of eflags: VIF           IF
+ *                         |
+ *                         +------------+
+ *                                      |
+ *                                      v
+ * Stack image of eflags: VIF           IF
+ *
+ * Notes: VIF on the stack image could be cleared, if it matters.
+ */
+
+#ifdef __ASSEMBLY__           /* For *.S assembly. */
+#define PUSHFL \
+   pushfl                   ; \
+   pushfl                   ; \
+   testl $(1<<19), 4(%esp)  ; \
+   jz 69001f                ; \
+   orl   $(1<<9), 4(%esp)   ; \
+   jmp 69002f               ; \
+   69001:                   ; \
+   andl  $~(1<<9), 4(%esp)  ; \
+   69002:                   ; \
+   popfl
+#else                         /* For *.C assembly. */
+#define PUSHFL \
+  "pushfl                     \n\t" /* Final eflags stack image. */ \
+  "pushfl                     \n\t" /* For restoring arithmetic flags. */ \
+  "testl $(1<<19), 4(%%esp)   \n\t" /* Was VIF bit set? */ \
+  "jz 69001f                  \n\t" \
+  "orl   $(1<<9), 4(%%esp)    \n\t" /* Yes: set stack image of IF. */ \
+  "jmp 69002f                 \n\t" \
+  "69001:                     \n\t" /* Use the zip of Lyon France :^) */ \
+  "andl  $~(1<<9), 4(%%esp)   \n\t" /* No: clear stack image of IF. */ \
+  "69002:                     \n\t" \
+  "popfl                      \n\t" /* Restore arithmetic flags. */
+#endif
+
+
+
+/* POPFL:
+ * When execution is monitored using PVI (Protected mode Virtual Interrupts),
+ * we have to complete the PVI semantics of the POPFL instruction, as
+ * per behaviour of VME.
+ *
+ *                        b19           b9
+ * Stack image of eflags: VIF           IF
+ *                                      |
+ *                         +------------+
+ *                         |
+ *                         v
+ * CPU   image of eflags: VIF           IF
+ *
+ * Notes: IF of the eflags register retains its previous value, which
+ *   should be 1 (when monitored down to PL3, the processor ignores this
+ *   bit in a POPF).
+ */
+
+#ifdef __ASSEMBLY__           /* For *.S assembly. */
+#define POPFL \
+   testl $(1<<9), 0(%esp)  ; \
+   jz 69003f               ; \
+   popfl                   ; \
+   sti                     ; \
+   jmp 69004f              ; \
+   69003:                  ; \
+   popfl                   ; \
+   cli                     ; \
+   69004:                
+#else                         /* For *.C assembly. */
+#define POPFL \
+  "testl $(1<<9), 0(%%esp)    \n\t" /* Is IF set on stack image? */ \
+  "jz 69003f                  \n\t" \
+  "popfl                      \n\t" /* Yes: restore from stack and */ \
+  "sti                        \n\t" /* force VIF=1. */ \
+  "jmp 69004f                 \n\t" \
+  "69003:                     \n\t" \
+  "popfl                      \n\t" /* No: restore from stack and */ \
+  "cli                        \n\t" /* force VIF=0. */ \
+  "69004:                     \n\t"
+#endif
+
+
+#endif  /* CONFIG_X86_HAL */
+
+
+#endif  /* _LINUX_ASM_IF_H_ */
diff -urN linux-2.5.59/include/asm-i386/system.h linux-2.5.59-hal/include/asm-i386/system.h
--- linux-2.5.59/include/asm-i386/system.h	Tue Jan 14 00:58:03 2003
+++ linux-2.5.59-hal/include/asm-i386/system.h	Tue Jan 21 18:34:08 2003
@@ -5,6 +5,7 @@
 #include <linux/kernel.h>
 #include <asm/segment.h>
 #include <linux/bitops.h> /* for LOCK_PREFIX */
+#include <asm/if.h>
 
 #ifdef __KERNEL__
 
@@ -12,7 +13,7 @@
 extern void FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));
 
 #define switch_to(prev,next,last) do {					\
-	asm volatile("pushfl\n\t"					\
+	asm volatile(PUSHFL      					\
 		     "pushl %%esi\n\t"					\
 		     "pushl %%edi\n\t"					\
 		     "pushl %%ebp\n\t"					\
@@ -25,7 +26,7 @@
 		     "popl %%ebp\n\t"					\
 		     "popl %%edi\n\t"					\
 		     "popl %%esi\n\t"					\
-		     "popfl\n\t"					\
+		     POPFL      					\
 		     :"=m" (prev->thread.esp),"=m" (prev->thread.eip)	\
 		     :"m" (next->thread.esp),"m" (next->thread.eip),	\
 		      "a" (prev), "d" (next));				\
@@ -380,8 +381,8 @@
 #define set_wmb(var, value) do { var = value; wmb(); } while (0)
 
 /* interrupt control.. */
-#define local_save_flags(x)	__asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */)
-#define local_irq_restore(x) 	__asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc")
+#define local_save_flags(x)	__asm__ __volatile__(PUSHFL " ; popl %0":"=g" (x): /* no input */)
+#define local_irq_restore(x) 	__asm__ __volatile__("pushl %0 ; " POPFL : /* no output */ :"g" (x):"memory", "cc")
 #define local_irq_disable() 	__asm__ __volatile__("cli": : :"memory")
 #define local_irq_enable()	__asm__ __volatile__("sti": : :"memory")
 /* used in the idle loop; sti takes one instruction cycle to complete */
@@ -395,7 +396,7 @@
 })
 
 /* For spinlocks etc */
-#define local_irq_save(x)	__asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory")
+#define local_irq_save(x)	__asm__ __volatile__(PUSHFL " ; popl %0 ; cli":"=g" (x): /* no input */ :"memory")
 
 /*
  * disable hlt during certain critical i/o operations