From: Pekka Enberg <penberg@cs.helsinki.fi>
Date: Thu, 8 Jul 2010 18:27:35 +0000 (+0300)
Subject: kvm: BIOS E820 memory map emulation
X-Git-Tag: next-20110824~3^2~528^2~102
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=febd1686dfd888dd7e2b69e7eeb1935987d4869b;p=karo-tx-linux.git

kvm: BIOS E820 memory map emulation

This patch adds BIOS E820 memory map emulation to KVM.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index a6f73f888bb5..eef578d784cc 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -87,10 +87,12 @@ bios/int10.o: bios/int10.S bios/int10-real.S
 	$(Q) $(CC) $(CFLAGS) -c bios/int10.S -o bios/int10.o
 
 bios/int15.o: bios/int10.S bios/int15-real.S
+	$(E) "  CC      " $@
+	$(Q) $(CC) -include code16gcc.h $(CFLAGS) $(BIOS_CFLAGS) -c -s bios/e820.c -o bios/e820.o
 	$(E) "  CC      " $@
 	$(Q) $(CC) $(CFLAGS) $(BIOS_CFLAGS) -c -s bios/int15-real.S -o bios/int15-real.o
 	$(E) "  LD      " $@
-	$(Q) ld -T bios/bios-strip.ld.S -o bios/int15-real.bin.elf bios/int15-real.o
+	$(Q) ld -T bios/bios-strip.ld.S -o bios/int15-real.bin.elf bios/int15-real.o bios/e820.o
 	$(E) "  OBJCOPY " $@
 	$(Q) objcopy -O binary -j .text bios/int15-real.bin.elf bios/int15-real.bin
 	$(Q) $(CC) $(CFLAGS) -c bios/int15.S -o bios/int15.o
diff --git a/tools/kvm/bios/e820.c b/tools/kvm/bios/e820.c
new file mode 100644
index 000000000000..4032871849a8
--- /dev/null
+++ b/tools/kvm/bios/e820.c
@@ -0,0 +1,46 @@
+#include "kvm/e820.h"
+
+#include "kvm/bios.h"
+#include "kvm/util.h"
+
+static inline void outb(uint8_t v, uint16_t port)
+{
+	asm volatile("outb %0,%1" : : "a" (v), "dN" (port));
+}
+
+static inline uint8_t rdfs8(unsigned long addr)
+{
+	uint8_t v;
+	asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(uint8_t *)addr));
+	return v;
+}
+
+void e820_query_map(struct e820_query *query)
+{
+	uint8_t map_size;
+	uint32_t ndx;
+
+	ndx		= query->ebx;
+
+	map_size	= rdfs8(E820_MAP_SIZE);
+
+	if (ndx < map_size) {
+		unsigned long start;
+		unsigned int i;
+		uint8_t *p;
+
+		start	= E820_MAP_START + sizeof(struct e820_entry) * ndx;
+
+		p	= (void *) query->edi;
+
+		for (i = 0; i < sizeof(struct e820_entry); i++)
+			*p++	= rdfs8(start + i);
+	}
+
+	query->eax	= SMAP;
+	query->ecx	= 20;
+	query->ebx	= ++ndx;
+
+	if (ndx >= map_size)
+		query->ebx	= 0;	/* end of map */
+}
diff --git a/tools/kvm/bios/int15-real.S b/tools/kvm/bios/int15-real.S
index dc4f73489106..c30215fd0630 100644
--- a/tools/kvm/bios/int15-real.S
+++ b/tools/kvm/bios/int15-real.S
@@ -10,28 +10,39 @@
 
 #include "macro.S"
 
+#define EFLAGS_CF	(1 << 0)
+
 ENTRY(___int15)
-	jmp out
+	cmp $0xE820, %eax
+	jne out
+
+	pushw	%fs
+
+	pushl	%edx
+	pushl	%ecx
+	pushl	%edi
+	pushl	%ebx
+	pushl	%eax
+
+	xor	%ax, %ax
+	mov	%ax, %fs
 
-#	movl %cs, %eax
-#	movl %eax, %es
-#	movl $0x534D4150, %eax	# 'SMAP'
-#	movl $0, %ebx		# end of map
-#	movl $20, %ecx
-#	mov e820entry_start, %di
-#	mov $(e820entry_end - e820entry_start), %ecx
+	movl	%esp, %eax
+	call	e820_query_map
 
+	popl	%eax
+	popl	%ebx
+	popl	%edi
+	popl	%ecx
+	popl	%edx
+
+	popw	%fs
+
+	/* Clear CF */
+	andl	$~EFLAGS_CF, 0x4(%esp)
 out:
 	sti
 	IRET
-/*
- * private IRQ data
- */
-GLOBAL(e820entry_start)
-	e820entry_addr:	.quad 0
-	e820entry_size:	.quad 0
-	e820entry_type:	.long 0
-GLOBAL(e820entry_end)
 
 /*
  * must be last in this file
diff --git a/tools/kvm/code16gcc.h b/tools/kvm/code16gcc.h
new file mode 100644
index 000000000000..d93e48010b61
--- /dev/null
+++ b/tools/kvm/code16gcc.h
@@ -0,0 +1,15 @@
+/*
+ * code16gcc.h
+ *
+ * This file is -include'd when compiling 16-bit C code.
+ * Note: this asm() needs to be emitted before gcc emits any code.
+ * Depending on gcc version, this requires -fno-unit-at-a-time or
+ * -fno-toplevel-reorder.
+ *
+ * Hopefully gcc will eventually have a real -m16 option so we can
+ * drop this hack long term.
+ */
+
+#ifndef __ASSEMBLY__
+asm(".code16gcc");
+#endif
diff --git a/tools/kvm/include/kvm/bios.h b/tools/kvm/include/kvm/bios.h
index 6767bd980f05..e5730841a6a9 100644
--- a/tools/kvm/include/kvm/bios.h
+++ b/tools/kvm/include/kvm/bios.h
@@ -18,6 +18,15 @@
 #define REAL_MODE_IVT_BEGIN		0x00000000
 #define REAL_MODE_IVT_END		0x000003ff
 
+#define BDA_START			0x00000400UL
+#define BDA_END				0x000004FFUL
+
+#define EBDA_START			0x0009FC00UL
+#define EBDA_END			0x0009FFFFUL
+
+#define E820_MAP_SIZE			EBDA_START
+#define E820_MAP_START			(EBDA_START + 0x01)
+
 #define MB_BIOS_BEGIN			0x000f0000
 #define MB_BIOS_END			0x000fffff
 
@@ -39,14 +48,6 @@
 #define MB_BIOS_SS			0xFFF7
 #define MB_BIOS_SP			0x40
 
-#define E820_RAM	1
-#define E820_RESERVED	2
-#define E820_ACPI	3
-#define E820_NVS	4
-#define E820_UNUSABLE	5
-
-#define E820_MAP_OFFSET	64
-
 #define ALIGN(x, a)	\
 	(((x) + ((a) - 1)) & ~((a) - 1))
 
diff --git a/tools/kvm/include/kvm/e820.h b/tools/kvm/include/kvm/e820.h
new file mode 100644
index 000000000000..8cde73835fde
--- /dev/null
+++ b/tools/kvm/include/kvm/e820.h
@@ -0,0 +1,27 @@
+#ifndef KVM_E820_H
+#define KVM_E820_H
+
+#include <stdint.h>
+
+#define SMAP    0x534d4150      /* ASCII "SMAP" */
+
+#define E820_MEM_USABLE		1
+#define E820_MEM_RESERVED	2
+
+struct e820_entry {
+	uint64_t addr;	/* start of memory segment */
+	uint64_t size;	/* size of memory segment */
+	uint32_t type;	/* type of memory segment */
+} __attribute__((packed));
+
+struct e820_query {
+	uint32_t	eax;
+	uint32_t	ebx;
+	uint32_t	edi;
+	uint32_t	ecx;
+	uint32_t	edx;
+};
+
+void e820_query_map(struct e820_query *query);
+
+#endif /* KVM_E820_H */
diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index d7f4685bf777..7acca0e1589c 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -37,6 +37,7 @@ void kvm__setup_cpuid(struct kvm *self);
 void kvm__enable_singlestep(struct kvm *self);
 bool kvm__load_kernel(struct kvm *kvm, const char *kernel_filename, const char *kernel_cmdline);
 void kvm__reset_vcpu(struct kvm *self);
+void kvm__setup_mem(struct kvm *self);
 void kvm__run(struct kvm *self);
 bool kvm__emulate_io(struct kvm *self, uint16_t port, void *data, int direction, int size, uint32_t count);
 bool kvm__emulate_mmio(struct kvm *self, uint64_t phys_addr, uint8_t *data, uint32_t len, uint8_t is_write);
diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index a2bedcaf449f..045fcd8729b3 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -2,6 +2,7 @@
 
 #include "kvm/interrupt.h"
 #include "kvm/cpufeature.h"
+#include "kvm/e820.h"
 #include "kvm/util.h"
 
 #include <linux/kvm.h>
@@ -526,6 +527,38 @@ void kvm__reset_vcpu(struct kvm *self)
 	kvm__setup_msrs(self);
 }
 
+void kvm__setup_mem(struct kvm *self)
+{
+	struct e820_entry *mem_map;
+	unsigned char *size;
+
+	size		= guest_flat_to_host(self, E820_MAP_SIZE);
+	mem_map		= guest_flat_to_host(self, E820_MAP_START);
+
+	*size		= 4;
+
+	mem_map[0]	= (struct e820_entry) {
+		.addr		= REAL_MODE_IVT_BEGIN,
+		.size		= BDA_END - REAL_MODE_IVT_BEGIN,
+		.type		= E820_MEM_RESERVED,
+	};
+	mem_map[1]	= (struct e820_entry) {
+		.addr		= BDA_END,
+		.size		= EBDA_END - BDA_END,
+		.type		= E820_MEM_USABLE,
+	};
+	mem_map[2]	= (struct e820_entry) {
+		.addr		= EBDA_END,
+		.size		= BZ_KERNEL_START - EBDA_END,
+		.type		= E820_MEM_RESERVED,
+	};
+	mem_map[3]	= (struct e820_entry) {
+		.addr		= BZ_KERNEL_START,
+		.size		= self->ram_size - BZ_KERNEL_START,
+		.type		= E820_MEM_USABLE,
+	};
+}
+
 void kvm__run(struct kvm *self)
 {
 	if (ioctl(self->vcpu_fd, KVM_RUN, 0) < 0)
diff --git a/tools/kvm/main.c b/tools/kvm/main.c
index 6711f85d1ef3..57ae33babdcf 100644
--- a/tools/kvm/main.c
+++ b/tools/kvm/main.c
@@ -93,6 +93,8 @@ int main(int argc, char *argv[])
 
 	kvm__reset_vcpu(kvm);
 
+	kvm__setup_mem(kvm);
+
 	if (single_step)
 		kvm__enable_singlestep(kvm);