Implement a simple native VM86 backend for X86BIOS. Now i386 uses native

VM86 calls instead of the real mode emulator as a backend.  VM86 has been
proven reliable for very long time and it is actually few times faster than
emulation.  Increase maximum number of page table entries per VM86 context
from 3 to 8 pages.  It was (ridiculously) low and insufficient for new VM86
backend, which shares one context globally.  Slighly rearrange and clean up
the emulator backend to accommodate new code.  The only visible change here
is stack size, which is decreased from 64K to 4K bytes to sync. with VM86.
Actually, it seems there is no need for big stack in real mode.

MFC after:	1 month

2 files changed, 266 insertions, 76 deletions

diff --git a/sys/compat/x86bios/x86bios.c b/sys/compat/x86bios/x86bios.c
index 22f1b93..94b2869 100644
--- a/sys/compat/x86bios/x86bios.c
+++ b/sys/compat/x86bios/x86bios.c
@@ -37,7 +37,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/module.h>
 #include <sys/mutex.h>
-#include <sys/proc.h>
 #include <sys/sysctl.h>
 
 #include <contrib/x86emu/x86emu.h>
@@ -47,36 +46,237 @@ __FBSDID("$FreeBSD$");
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcivar.h>
 
-#include <machine/iodev.h>
-
 #include <vm/vm.h>
 #include <vm/pmap.h>
 
-#if defined(__amd64__) || defined(__i386__)
+#ifdef __amd64__
 #define	X86BIOS_NATIVE_ARCH
 #endif
+#ifdef __i386__
+#define	X86BIOS_NATIVE_VM86
+#endif
+
+#define	X86BIOS_MEM_SIZE	0x00100000	/* 1M */
+
+static struct mtx x86bios_lock;
+
+SYSCTL_NODE(_debug, OID_AUTO, x86bios, CTLFLAG_RD, NULL, "x86bios debugging");
+static int x86bios_trace_call;
+TUNABLE_INT("debug.x86bios.call", &x86bios_trace_call);
+SYSCTL_INT(_debug_x86bios, OID_AUTO, call, CTLFLAG_RW, &x86bios_trace_call, 0,
+    "Trace far function calls");
+static int x86bios_trace_int;
+TUNABLE_INT("debug.x86bios.int", &x86bios_trace_int);
+SYSCTL_INT(_debug_x86bios, OID_AUTO, int, CTLFLAG_RW, &x86bios_trace_int, 0,
+    "Trace software interrupt handlers");
+
+#ifdef X86BIOS_NATIVE_VM86
+
+#include <machine/vm86.h>
+#include <machine/vmparam.h>
+#include <machine/pc/bios.h>
+
+struct vm86context x86bios_vmc;
+
+static void
+x86bios_emu2vmf(struct x86emu_regs *regs, struct vm86frame *vmf)
+{
+
+	vmf->vmf_ds = regs->R_DS;
+	vmf->vmf_es = regs->R_ES;
+	vmf->vmf_ss = regs->R_SS;
+	vmf->vmf_flags = regs->R_FLG;
+	vmf->vmf_ax = regs->R_AX;
+	vmf->vmf_bx = regs->R_BX;
+	vmf->vmf_cx = regs->R_CX;
+	vmf->vmf_dx = regs->R_DX;
+	vmf->vmf_sp = regs->R_SP;
+	vmf->vmf_bp = regs->R_BP;
+	vmf->vmf_si = regs->R_SI;
+	vmf->vmf_di = regs->R_DI;
+}
+
+static void
+x86bios_vmf2emu(struct vm86frame *vmf, struct x86emu_regs *regs)
+{
+
+	regs->R_DS = vmf->vmf_ds;
+	regs->R_ES = vmf->vmf_es;
+	regs->R_SS = vmf->vmf_ss;
+	regs->R_FLG = vmf->vmf_flags;
+	regs->R_AX = vmf->vmf_ax;
+	regs->R_BX = vmf->vmf_bx;
+	regs->R_CX = vmf->vmf_cx;
+	regs->R_DX = vmf->vmf_dx;
+	regs->R_SP = vmf->vmf_sp;
+	regs->R_BP = vmf->vmf_bp;
+	regs->R_SI = vmf->vmf_si;
+	regs->R_DI = vmf->vmf_di;
+}
+
+void *
+x86bios_alloc(uint32_t *offset, size_t size, int flags)
+{
+	vm_offset_t addr;
+	int i;
+
+	addr = (vm_offset_t)contigmalloc(size, M_DEVBUF, flags, 0,
+	    X86BIOS_MEM_SIZE, PAGE_SIZE, 0);
+	if (addr != 0) {
+		*offset = vtophys(addr);
+		mtx_lock(&x86bios_lock);
+		for (i = 0; i < howmany(size, PAGE_SIZE); i++)
+			vm86_addpage(&x86bios_vmc, atop(*offset),
+			    addr + i * PAGE_SIZE);
+		mtx_unlock(&x86bios_lock);
+	}
+
+	return ((void *)addr);
+}
+
+void
+x86bios_free(void *addr, size_t size)
+{
+	int i, last;
+
+	mtx_lock(&x86bios_lock);
+	for (i = 0, last = -1; i < x86bios_vmc.npages; i++)
+		if (x86bios_vmc.pmap[i].kva >= (vm_offset_t)addr &&
+		    x86bios_vmc.pmap[i].kva < (vm_offset_t)addr + size) {
+			bzero(&x86bios_vmc.pmap[i],
+			    sizeof(x86bios_vmc.pmap[i]));
+			last = i;
+		}
+	if (last == x86bios_vmc.npages - 1) {
+		x86bios_vmc.npages -= howmany(size, PAGE_SIZE);
+		for (i = x86bios_vmc.npages - 1;
+		    i >= 0 && x86bios_vmc.pmap[i].kva == 0; i--)
+			x86bios_vmc.npages--;
+	}
+	mtx_unlock(&x86bios_lock);
+	contigfree(addr, size, M_DEVBUF);
+}
+
+void
+x86bios_init_regs(struct x86regs *regs)
+{
+
+	bzero(regs, sizeof(*regs));
+}
+
+void
+x86bios_call(struct x86regs *regs, uint16_t seg, uint16_t off)
+{
+	struct vm86frame vmf;
+
+	if (x86bios_trace_call)
+		printf("Calling 0x%05x (ax=0x%04x bx=0x%04x "
+		    "cx=0x%04x dx=0x%04x es=0x%04x di=0x%04x)\n",
+		    (seg << 4) + off, regs->R_AX, regs->R_BX, regs->R_CX,
+		    regs->R_DX, regs->R_ES, regs->R_DI);
+
+	bzero(&vmf, sizeof(vmf));
+	x86bios_emu2vmf((struct x86emu_regs *)regs, &vmf);
+	vmf.vmf_cs = seg;
+	vmf.vmf_ip = off;
+	mtx_lock(&x86bios_lock);
+	vm86_datacall(-1, &vmf, &x86bios_vmc);
+	mtx_unlock(&x86bios_lock);
+	x86bios_vmf2emu(&vmf, (struct x86emu_regs *)regs);
+
+	if (x86bios_trace_call)
+		printf("Exiting 0x%05x (ax=0x%04x bx=0x%04x "
+		    "cx=0x%04x dx=0x%04x es=0x%04x di=0x%04x)\n",
+		    (seg << 4) + off, regs->R_AX, regs->R_BX, regs->R_CX,
+		    regs->R_DX, regs->R_ES, regs->R_DI);
+}
+
+uint32_t
+x86bios_get_intr(int intno)
+{
+
+	return (readl(x86bios_offset(intno * 4)));
+}
+
+void
+x86bios_intr(struct x86regs *regs, int intno)
+{
+	struct vm86frame vmf;
+
+	if (x86bios_trace_int)
+		printf("Calling int 0x%x (ax=0x%04x bx=0x%04x "
+		    "cx=0x%04x dx=0x%04x es=0x%04x di=0x%04x)\n",
+		    intno, regs->R_AX, regs->R_BX, regs->R_CX,
+		    regs->R_DX, regs->R_ES, regs->R_DI);
+
+	bzero(&vmf, sizeof(vmf));
+	x86bios_emu2vmf((struct x86emu_regs *)regs, &vmf);
+	mtx_lock(&x86bios_lock);
+	vm86_datacall(intno, &vmf, &x86bios_vmc);
+	mtx_unlock(&x86bios_lock);
+	x86bios_vmf2emu(&vmf, (struct x86emu_regs *)regs);
+
+	if (x86bios_trace_int)
+		printf("Exiting int 0x%x (ax=0x%04x bx=0x%04x "
+		    "cx=0x%04x dx=0x%04x es=0x%04x di=0x%04x)\n",
+		    intno, regs->R_AX, regs->R_BX, regs->R_CX,
+		    regs->R_DX, regs->R_ES, regs->R_DI);
+}
+
+void *
+x86bios_offset(uint32_t offset)
+{
+	vm_offset_t addr;
+
+	addr = vm86_getaddr(&x86bios_vmc, X86BIOS_PHYSTOSEG(offset),
+	    X86BIOS_PHYSTOOFF(offset));
+	if (addr == 0)
+		addr = BIOS_PADDRTOVADDR(offset);
+
+	return ((void *)addr);
+}
+
+static int
+x86bios_init(void)
+{
+
+	mtx_init(&x86bios_lock, "x86bios lock", NULL, MTX_DEF);
+	bzero(&x86bios_vmc, sizeof(x86bios_vmc));
+
+	return (0);
+}
+
+static int
+x86bios_uninit(void)
+{
+
+	mtx_destroy(&x86bios_lock);
+
+	return (0);
+}
+
+#else
+
+#include <machine/iodev.h>
 
 #define	X86BIOS_PAGE_SIZE	0x00001000	/* 4K */
 
 #define	X86BIOS_IVT_SIZE	0x00000500	/* 1K + 256 (BDA) */
-#define	X86BIOS_SEG_SIZE	0x00010000	/* 64K */
-#define	X86BIOS_MEM_SIZE	0x00100000	/* 1M */
 
 #define	X86BIOS_IVT_BASE	0x00000000
 #define	X86BIOS_RAM_BASE	0x00001000
 #define	X86BIOS_ROM_BASE	0x000a0000
 
 #define	X86BIOS_ROM_SIZE	(X86BIOS_MEM_SIZE - (uint32_t)x86bios_rom_phys)
+#define	X86BIOS_SEG_SIZE	X86BIOS_PAGE_SIZE
 
 #define	X86BIOS_PAGES		(X86BIOS_MEM_SIZE / X86BIOS_PAGE_SIZE)
 
-#define	X86BIOS_R_DS		_pad1
 #define	X86BIOS_R_SS		_pad2
+#define	X86BIOS_R_SP		_pad3.I16_reg.x_reg
 
 static struct x86emu x86bios_emu;
 
-static struct mtx x86bios_lock;
-
 static void *x86bios_ivt;
 static void *x86bios_rom;
 static void *x86bios_seg;
@@ -91,16 +291,6 @@ static uint32_t x86bios_fault_addr;
 static uint16_t x86bios_fault_cs;
 static uint16_t x86bios_fault_ip;
 
-SYSCTL_NODE(_debug, OID_AUTO, x86bios, CTLFLAG_RD, NULL, "x86bios debugging");
-static int x86bios_trace_call;
-TUNABLE_INT("debug.x86bios.call", &x86bios_trace_call);
-SYSCTL_INT(_debug_x86bios, OID_AUTO, call, CTLFLAG_RW, &x86bios_trace_call, 0,
-    "Trace far function calls");
-static int x86bios_trace_int;
-TUNABLE_INT("debug.x86bios.int", &x86bios_trace_int);
-SYSCTL_INT(_debug_x86bios, OID_AUTO, int, CTLFLAG_RW, &x86bios_trace_int, 0,
-    "Trace software interrupt handlers");
-
 static void
 x86bios_set_fault(struct x86emu *emu, uint32_t addr)
 {
@@ -115,18 +305,18 @@ x86bios_set_fault(struct x86emu *emu, uint32_t addr)
 static void *
 x86bios_get_pages(uint32_t offset, size_t size)
 {
-	vm_offset_t page;
+	vm_offset_t addr;
 
 	if (offset + size > X86BIOS_MEM_SIZE + X86BIOS_IVT_SIZE)
 		return (NULL);
 
 	if (offset >= X86BIOS_MEM_SIZE)
 		offset -= X86BIOS_MEM_SIZE;
-	page = x86bios_map[offset / X86BIOS_PAGE_SIZE];
-	if (page != 0)
-		return ((void *)(page + offset % X86BIOS_PAGE_SIZE));
+	addr = x86bios_map[offset / X86BIOS_PAGE_SIZE];
+	if (addr != 0)
+		addr += offset % X86BIOS_PAGE_SIZE;
 
-	return (NULL);
+	return ((void *)addr);
 }
 
 static void
@@ -393,8 +583,8 @@ x86bios_init_regs(struct x86regs *regs)
 {
 
 	bzero(regs, sizeof(*regs));
-	regs->X86BIOS_R_DS = 0x40;
-	regs->X86BIOS_R_SS = x86bios_seg_phys >> 4;
+	regs->X86BIOS_R_SS = X86BIOS_PHYSTOSEG(x86bios_seg_phys);
+	regs->X86BIOS_R_SP = X86BIOS_PAGE_SIZE - 2;
 }
 
 void
@@ -481,51 +671,6 @@ x86bios_offset(uint32_t offset)
 	return (x86bios_get_pages(offset, 1));
 }
 
-void *
-x86bios_get_orm(uint32_t offset)
-{
-	uint8_t *p;
-
-	/* Does the shadow ROM contain BIOS POST code for x86? */
-	p = x86bios_offset(offset);
-	if (p == NULL || p[0] != 0x55 || p[1] != 0xaa || p[3] != 0xe9)
-		return (NULL);
-
-	return (p);
-}
-
-int
-x86bios_match_device(uint32_t offset, device_t dev)
-{
-	uint8_t *p;
-	uint16_t device, vendor;
-	uint8_t class, progif, subclass;
-
-	/* Does the shadow ROM contain BIOS POST code for x86? */
-	p = x86bios_get_orm(offset);
-	if (p == NULL)
-		return (0);
-
-	/* Does it contain PCI data structure? */
-	p += le16toh(*(uint16_t *)(p + 0x18));
-	if (bcmp(p, "PCIR", 4) != 0 ||
-	    le16toh(*(uint16_t *)(p + 0x0a)) < 0x18 || *(p + 0x14) != 0)
-		return (0);
-
-	/* Does it match the vendor, device, and classcode? */
-	vendor = le16toh(*(uint16_t *)(p + 0x04));
-	device = le16toh(*(uint16_t *)(p + 0x06));
-	progif = *(p + 0x0d);
-	subclass = *(p + 0x0e);
-	class = *(p + 0x0f);
-	if (vendor != pci_get_vendor(dev) || device != pci_get_device(dev) ||
-	    class != pci_get_class(dev) || subclass != pci_get_subclass(dev) ||
-	    progif != pci_get_progif(dev))
-		return (0);
-
-	return (1);
-}
-
 static __inline void
 x86bios_unmap_mem(void)
 {
@@ -549,7 +694,6 @@ x86bios_map_mem(void)
 #ifdef X86BIOS_NATIVE_ARCH
 	x86bios_ivt = pmap_mapbios(X86BIOS_IVT_BASE, X86BIOS_IVT_SIZE);
 
-#ifndef PC98
 	/* Probe EBDA via BDA. */
 	x86bios_rom_phys = *(uint16_t *)((caddr_t)x86bios_ivt + 0x40e);
 	x86bios_rom_phys = x86bios_rom_phys << 4;
@@ -558,7 +702,6 @@ x86bios_map_mem(void)
 		x86bios_rom_phys =
 		    rounddown(x86bios_rom_phys, X86BIOS_PAGE_SIZE);
 	else
-#endif
 #else
 	x86bios_ivt = malloc(X86BIOS_IVT_SIZE, M_DEVBUF, M_ZERO | M_WAITOK);
 #endif
@@ -567,7 +710,7 @@ x86bios_map_mem(void)
 	x86bios_rom = pmap_mapdev(x86bios_rom_phys, X86BIOS_ROM_SIZE);
 	if (x86bios_rom == NULL)
 		goto fail;
-#if defined(X86BIOS_NATIVE_ARCH) && !defined(PC98)
+#ifdef X86BIOS_NATIVE_ARCH
 	/* Change attribute for EBDA. */
 	if (x86bios_rom_phys < X86BIOS_ROM_BASE &&
 	    pmap_change_attr((vm_offset_t)x86bios_rom,
@@ -666,6 +809,53 @@ x86bios_uninit(void)
 	return (0);
 }
 
+#endif
+
+void *
+x86bios_get_orm(uint32_t offset)
+{
+	uint8_t *p;
+
+	/* Does the shadow ROM contain BIOS POST code for x86? */
+	p = x86bios_offset(offset);
+	if (p == NULL || p[0] != 0x55 || p[1] != 0xaa || p[3] != 0xe9)
+		return (NULL);
+
+	return (p);
+}
+
+int
+x86bios_match_device(uint32_t offset, device_t dev)
+{
+	uint8_t *p;
+	uint16_t device, vendor;
+	uint8_t class, progif, subclass;
+
+	/* Does the shadow ROM contain BIOS POST code for x86? */
+	p = x86bios_get_orm(offset);
+	if (p == NULL)
+		return (0);
+
+	/* Does it contain PCI data structure? */
+	p += le16toh(*(uint16_t *)(p + 0x18));
+	if (bcmp(p, "PCIR", 4) != 0 ||
+	    le16toh(*(uint16_t *)(p + 0x0a)) < 0x18 || *(p + 0x14) != 0)
+		return (0);
+
+	/* Does it match the vendor, device, and classcode? */
+	vendor = le16toh(*(uint16_t *)(p + 0x04));
+	device = le16toh(*(uint16_t *)(p + 0x06));
+	progif = *(p + 0x0d);
+	subclass = *(p + 0x0e);
+	class = *(p + 0x0f);
+	if (vendor != pci_get_vendor(dev) || device != pci_get_device(dev) ||
+	    class != pci_get_class(dev) || subclass != pci_get_subclass(dev) ||
+	    progif != pci_get_progif(dev))
+		return (0);
+
+	return (1);
+}
+
 static int
 x86bios_modevent(module_t mod __unused, int type, void *data __unused)
 {
diff --git a/sys/compat/x86bios/x86bios.h b/sys/compat/x86bios/x86bios.h
index 682c6f5..f474932 100644
--- a/sys/compat/x86bios/x86bios.h
+++ b/sys/compat/x86bios/x86bios.h
@@ -138,8 +138,8 @@ typedef struct x86regs	x86regs_t;
 #define	R_FS		register_fs
 #define	R_GS		register_gs
 
-#define	X86BIOS_PHYSTOSEG(x)	(((x) >> 4) & 0xffff)
-#define	X86BIOS_PHYSTOOFF(x)	((x) & 0x000f)
+#define	X86BIOS_PHYSTOSEG(x)	(((x) >> 4) & 0xff00)
+#define	X86BIOS_PHYSTOOFF(x)	((x) & 0x0fff)
 
 __BEGIN_DECLS
 void	*x86bios_alloc(uint32_t *offset, size_t size, int flags);