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devvmx: more efficient data structure for memory map; simplified (more reliable) step function

--- a/sys/src/9/pc/devvmx.c

+++ b/sys/src/9/pc/devvmx.c

@@ -223,7 +223,7 @@

 typedef struct VmIntr VmIntr;

 struct VmMem {

-	uvlong lo, hi;

+	uvlong addr;

 	Segment *seg;

 	uintptr off;

 	char *name;

@@ -271,10 +271,7 @@

 	enum {

 		GOTEXIT = 1,

 		GOTIRQACK = 2,

-		GOTSTEP = 4,

-		GOTSTEPERR = 8,

 	} got;

-	VmMem *stepmap;

 	VmIntr exc, irq, irqack;

 	u64int *msrhost, *msrguest;

@@ -619,11 +616,11 @@

 }

 static void

-epttranslate(VmMem *mp)

+epttranslate(VmMem *mp, uvlong end)

 {

 	uvlong p, v;

-	if((mp->lo & 0xfff) != 0 || (mp->hi & 0xfff) != 0 || (uint)mp->attr >= 0x1000)

+	if((mp->addr & 0xfff) != 0 || (end & 0xfff) != 0 || (uint)mp->attr >= 0x1000)

 		error(Egreg);

 	if(mp->seg != nil){

 		switch(mp->seg->type & SG_TYPE){

@@ -633,13 +630,13 @@

 		case SG_STICKY:

 			break;

 		}

-		if(mp->seg->base + mp->off + (mp->hi - mp->lo) > mp->seg->top)

+		if(mp->seg->base + mp->off + (end - mp->addr) > mp->seg->top)

 			error(Egreg);

-		for(p = mp->lo, v = mp->off; p < mp->hi; p += BY2PG, v += BY2PG)

+		for(p = mp->addr, v = mp->off; p != end; p += BY2PG, v += BY2PG)

 			*eptwalk(p) = mp->seg->map[v/PTEMAPMEM]->pages[(v & PTEMAPMEM-1)/BY2PG]->pa | mp->attr;

 	}else {

-		for(p = mp->lo; p < mp->hi; p += BY2PG)

-			*eptwalk(p) = mp->attr;

+		for(p = mp->addr; p != end; p += BY2PG)

+			*eptwalk(p) = 0;

 	}

 	vmx.onentry |= FLUSHEPT;

 }

@@ -657,7 +654,10 @@

 	p0 = va_arg(va, char *);

 	e = va_arg(va, char *);

 	p = p0;

+	if(p < e) *p = 0;

 	for(mp = vmx.mem.next; mp != &vmx.mem; mp = mp->next){

+		if(mp->seg == nil)

+			continue;

 		attr[0] = (mp->attr & 1) != 0 ? 'r' : '-';

 		attr[1] = (mp->attr & 2) != 0 ? 'w' : '-';

 		attr[2] = (mp->attr & 4) != 0 ? 'x' : '-';

@@ -665,26 +665,42 @@

 		*(ushort*)mt = *(u16int*)mtype[mp->attr >> 3 & 7];

 		mt[2] = (mp->attr & 0x40) != 0 ? '!' : 0;

 		mt[3] = 0;

-		if(mp->name == nil)

-			p = seprint(p, e, "%s %s %#llux %#llux\n", attr, mt, mp->lo, mp->hi);

-		else

-			p = seprint(p, e, "%s %s %#llux %#llux %s %#llux\n", attr, mt, mp->lo, mp->hi, mp->name, (uvlong)mp->off);

+		p = seprint(p, e, "%s %s %#llux %#llux %s %#llux\n", attr, mt, mp->addr, mp->next->addr, mp->name, (uvlong)mp->off);

 	}

 	return p - p0;

 }

+static void

+vmmeminsert(VmMem *l, VmMem *p)

+{

+	p->prev = l->prev;

+	p->next = l;

+	p->prev->next = p;

+	p->next->prev = p;

+}

+

+static VmMem *

+vmmemremove(VmMem *p)

+{

+	VmMem *r;

+	

+	r = p->next;

+	p->next->prev = p->prev;

+	p->prev->next = p->next;

+	free(p->name);

+	putseg(p->seg);

+	free(p);

+	return r;

+}

+

 static int

 cmdclearmeminfo(VmCmd *, va_list)

 {

-	VmMem *mp, *mn;

+	VmMem *mp;

 	eptfree(vmx.pml4, 0);

-	for(mp = vmx.mem.next; mp != &vmx.mem; mp = mn){

-		free(mp->name);

-		putseg(mp->seg);

-		mn = mp->next;

-		free(mp);

-	}

+	for(mp = vmx.mem.next; mp != &vmx.mem; )

+		mp = vmmemremove(mp);

 	vmx.mem.prev = &vmx.mem;

 	vmx.mem.next = &vmx.mem;

 	vmx.onentry |= FLUSHEPT;

@@ -691,6 +707,41 @@

 	return 0;

 }

+

+static void

+vmmemupdate(VmMem *mp, uvlong end)

+{

+	VmMem *p, *q;

+	

+	for(p = vmx.mem.prev; p != &vmx.mem; p = p->prev)

+		if(p->addr <= end || end == 0)

+			break;

+	if(p == &vmx.mem || p->addr < mp->addr){

+		q = smalloc(sizeof(VmMem));

+		*q = *p;

+		if(p->seg != nil){

+			incref(q->seg);

+			kstrdup(&q->name, p->name);

+		}

+		vmmeminsert(p->next, q);

+	}else

+		q = p;

+	if(q->seg != nil)

+		q->off += end - q->addr;

+	q->addr = end;

+	for(p = vmx.mem.next; p != &vmx.mem; p = p->next)

+		if(p->addr >= mp->addr)

+			break;

+	vmmeminsert(p, mp);

+	while(p != q)

+		p = vmmemremove(p);

+	for(p = vmx.mem.next; p != &vmx.mem; )

+		if(p->seg == p->prev->seg && (p->seg == nil || p->addr - p->prev->addr == p->off - p->prev->off))

+			p = vmmemremove(p);

+		else

+			p = p->next;

+}

+

 extern Segment* (*_globalsegattach)(char*);

 static int

@@ -701,6 +752,7 @@

 	char *f[10];

 	VmMem *mp;

 	int rc;

+	uvlong end;

 	if(vmx.pml4 == nil)

 		error(Egreg);	

@@ -725,7 +777,10 @@

 		}

 		rc = tokenize(p, f, nelem(f));

 		p = q + 1;

-		if(rc == 0) goto next;

+		if(rc == 0){

+			poperror();

+			continue;

+		}

 		if(rc != 4 && rc != 6) error("number of fields wrong");

 		for(q = f[0]; *q != 0; q++)

 			switch(*q){

@@ -743,27 +798,23 @@

 		if(j == 8 || strlen(f[1]) > 3) error("invalid memory type");

 		if(f[1][2] == '!') mp->attr |= 0x40;

 		else if(f[1][2] != 0) error("invalid memory type");

-		mp->lo = strtoull(f[2], &r, 0);

-		if(*r != 0 || !vmokpage(mp->lo)) error("invalid low guest physical address");

-		mp->hi = strtoull(f[3], &r, 0);

-		if(*r != 0 || !vmokpage(mp->hi) || mp->hi <= mp->lo) error("invalid high guest physical address");

-		mp->off = strtoull(f[5], &r, 0);

-		if(*r != 0 || !vmokpage(mp->off)) error("invalid offset");

+		mp->addr = strtoull(f[2], &r, 0);

+		if(*r != 0 || !vmokpage(mp->addr)) error("invalid low guest physical address");

+		end = strtoull(f[3], &r, 0);

+		if(*r != 0 || !vmokpage(end) || end <= mp->addr) error("invalid high guest physical address");

 		if((mp->attr & 7) != 0){

 			if(rc != 6) error("number of fields wrong");

 			mp->seg = _globalsegattach(f[4]);

 			if(mp->seg == nil) error("no such segment");

-			if(mp->seg->base + mp->off + (mp->hi - mp->lo) > mp->seg->top) error("out of bounds");

+			if(mp->seg->base + mp->off + (end - mp->addr) > mp->seg->top) error("out of bounds");

 			kstrdup(&mp->name, f[4]);

+			mp->off = strtoull(f[5], &r, 0);

+			if(*r != 0 || !vmokpage(mp->off)) error("invalid offset");

 		}

-		epttranslate(mp);

-		mp->prev = vmx.mem.prev;

-		mp->next = &vmx.mem;

-		mp->prev->next = mp;

-		mp->next->prev = mp;

-		mp = nil;

-	next:

 		poperror();

+		epttranslate(mp, end);

+		vmmemupdate(mp, end);

+		mp = nil;

 	}

 	free(mp);

 	return p - p0;

@@ -1089,7 +1140,6 @@

 	}

 	vmx.got = 0;

 	vmx.onentry = 0;

-	vmx.stepmap = nil;

 	free(vmx.msrhost);

 	free(vmx.msrguest);

@@ -1121,22 +1171,10 @@

 		case 7: /* IRQ window */

 		case 8: /* NMI window */

 			return;

-		case 37:

-			if((vmx.onentry & STEP) != 0){

-				vmx.state = VMXREADY;

-				vmx.got |= GOTSTEP;

-				vmx.onentry &= ~STEP;

-				return;

-			}

-			break;

 		}

-	if((vmx.onentry & STEP) != 0){

-		print("VMX: exit reason %#x when expected step...\n", reason & 0xffff);

-		vmx.onentry &= ~STEP;

-		vmx.got |= GOTSTEP|GOTSTEPERR;

-	}

 	vmx.state = VMXREADY;

 	vmx.got |= GOTEXIT;

+	vmx.onentry &= ~STEP;

 }

 static int

@@ -1252,12 +1290,15 @@

 static int

 cmdgo(VmCmd *, va_list va)

 {

+	int step;

 	char *r;

 	if(vmx.state != VMXREADY)

 		error("VM not ready");

+	step = va_arg(va, int);

 	r = va_arg(va, char *);

 	if(r != nil) setregs(r, ';', "=");

+	if(step) vmx.onentry |= STEP;

 	vmx.state = VMXRUNNING;

 	return 0;

 }

@@ -1342,43 +1383,6 @@

 	return p - p0;

 }

-static int

-cmdstep(VmCmd *cp, va_list va)

-{

-	switch(cp->retval){

-	case 0:

-		if((vmx.got & GOTSTEP) != 0 || (vmx.onentry & STEP) != 0)

-			error(Einuse);

-		if(vmx.state != VMXREADY){

-			print("pre-step in state %s\n", statenames[vmx.state]);

-			error("not ready");

-		}

-		vmx.stepmap = va_arg(va, VmMem *);

-		vmx.onentry |= STEP;

-		vmx.state = VMXRUNNING;

-		cp->flags |= CMDFPOSTP;

-		return 1;

-	case 1:

-		if(vmx.state != VMXREADY){

-			print("post-step in state %s\n", statenames[vmx.state]);

-			vmx.onentry &= ~STEP;

-			vmx.got &= ~(GOTSTEP|GOTSTEPERR);

-			error("not ready");

-		}

-		if((vmx.got & GOTSTEP) == 0){

-			cp->flags |= CMDFPOSTP;

-			return 1;

-		}

-		if((vmx.got & GOTSTEPERR) != 0){

-			vmx.got &= ~(GOTSTEP|GOTSTEPERR);

-			error("step failed");

-		}

-		vmx.got &= ~(GOTSTEP|GOTSTEPERR);

-		return 1;

-	}

-	return 0;

-}

-

 static void

 eventparse(char *p, VmIntr *vi)

 {

@@ -1548,28 +1552,6 @@

 }

 static void

-dostep(int setup)

-{

-	static uvlong oldmap;

-	static uvlong *mapptr;

-

-	if(setup){

-		if(vmx.stepmap != nil){

-			mapptr = eptwalk(vmx.stepmap->lo);

-			oldmap = *mapptr;

-			epttranslate(vmx.stepmap);

-		}

-	}else{

-		vmcswrite(PROCB_CTLS, vmcsread(PROCB_CTLS) & ~(uvlong)PROCB_MONTRAP);

-		if(vmx.stepmap != nil){

-			*mapptr = oldmap;

-			vmx.stepmap = nil;

-			vmx.onentry |= FLUSHEPT;

-		}

-	}

-}

-

-static void

 vmxproc(void *)

 {

 	int init, rc, x;

@@ -1594,14 +1576,8 @@

 		runcmd();

 		if(vmx.state == VMXRUNNING){

 			procbctls = defprocbctls;

-			if((vmx.onentry & STEP) != 0){

-				procbctls |= PROCB_MONTRAP;

-				dostep(1);

-				if(waserror()){

-					dostep(0);

-					nexterror();

-				}

-			}

+			if((vmx.onentry & STEP) != 0)

+				defprocbctls |= PROCB_MONTRAP;

 			if((vmx.onentry & POSTEX) != 0){

 				vmcswrite(VMENTRY_INTRINFO, vmx.exc.info);

 				vmcswrite(VMENTRY_INTRCODE, vmx.exc.code);

@@ -1648,10 +1624,6 @@

 			if(rc < 0)

 				error("vmlaunch failed");

 			vmx.launched = 1;

-			if((vmx.onentry & STEP) != 0){

-				dostep(0);

-				poperror();

-			}

 			processexit();

 		}else{

 			up->psstate = "Idle";

@@ -1853,8 +1825,6 @@

 	Cmdtab *ct;

 	char *s;

 	int rc;

-	int i;

-	VmMem tmpmem;

 	switch((ulong)c->qid.path){

 	case Qdir:

@@ -1886,6 +1856,7 @@

 			vmxcmd(cmdquit);

 			break;

 		case CMgo:

+		case CMstep:

 			s = nil;

 			if(cb->nf == 2) kstrdup(&s, cb->f[1]);

 			else if(cb->nf != 1) error(Ebadarg);

@@ -1893,32 +1864,12 @@

 				free(s);

 				nexterror();

 			}

-			vmxcmd(cmdgo, s);

+			vmxcmd(cmdgo, ct->index == CMstep, s);

 			poperror();

 			free(s);

 			break;

 		case CMstop:

 			vmxcmd(cmdstop);

-			break;

-		case CMstep:

-			rc = 0;

-			for(i = 1; i < cb->nf; i++)

-				if(strcmp(cb->f[i], "-map") == 0){

-					rc = 1;

-					if(i+4 > cb->nf) error("missing argument");

-					memset(&tmpmem, 0, sizeof(tmpmem));

-					tmpmem.lo = strtoull(cb->f[i+1], &s, 0);

-					if(*s != 0 || !vmokpage(tmpmem.lo)) error("invalid address");

-					tmpmem.hi = tmpmem.lo + BY2PG;

-					tmpmem.attr = 0x407;

-					tmpmem.seg = _globalsegattach(cb->f[i+2]);

-					if(tmpmem.seg == nil) error("unknown segment");

-					tmpmem.off = strtoull(cb->f[i+3], &s, 0);

-					if(*s != 0 || !vmokpage(tmpmem.off)) error("invalid offset");

-					i += 3;

-				}else

-					error(Ebadctl);

-			vmxcmd(cmdstep, rc ? &tmpmem : nil);

 			break;

 		case CMexc:

 			s = nil;