vmx(1): add support for (so far) crude 9p debugging fs; add gdb stub; clean up linux gdt code

1 files changed, 124 insertions, 0 deletions

diff --git a/sys/src/cmd/vmx/x86.c b/sys/src/cmd/vmx/x86.c
new file mode 100644
index 000000000..f7d60617b
--- /dev/null
+++ b/sys/src/cmd/vmx/x86.c
@@ -0,0 +1,124 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include "dat.h"
+#include "fns.h"
+#include "x86.h"
+
+typedef struct VMemReq VMemReq;
+struct VMemReq {
+	QLock;
+	uintptr va, len;
+	void *buf;
+	uintptr rc;
+};
+
+static uintptr
+translateflat(uintptr va, uintptr *pa, uintptr)
+{
+	*pa = va;
+	if(va == 0)
+		return -1;
+	return 0;
+}
+
+static uintptr
+translate32(uintptr va, uintptr *pa, uintptr cr4)
+{
+	void *pd, *pt;
+	u32int pde, pte;
+
+	if(sizeof(uintptr) != 4 && va >> 32 != 0) return -1;
+	pd = gptr(rget("cr3") & ~0xfff, 4096);
+	if(pd == nil) return 0;
+	pde = GET32(pd, (va >> 22) * 4);
+	if((pde & 1) == 0) return 0;
+	if((pde & 0x80) != 0 && (cr4 & Cr4Pse) != 0){
+		*pa = pde & (1<<22) - 1 | (uintptr)(pde & 0xfe000) << 19;
+		return (1<<22) - (va & (1<<22)-1);
+	}
+	pt = gptr(pde & ~0xfff, 4096);
+	if(pt == nil) return 0;
+	pte = GET32(pt, va >> 10 & 0xffc);
+	if((pte & 1) == 0) return 0;
+	*pa = pte & ~0xfff | va & 0xfff;
+	return 0x1000 - (va & 0xfff);
+}
+
+static uintptr
+translatepae(uintptr, uintptr *, uintptr)
+{
+	vmerror("PAE translation not implemented");
+	return 0;
+}
+
+static uintptr
+translate64(uintptr, uintptr *, uintptr)
+{
+	vmerror("long mode translation not implemented");
+	return 0;	
+}
+
+static uintptr (*
+translator(uintptr *cr4p))(uintptr, uintptr *, uintptr)
+{
+	uintptr cr0, cr4, efer;
+	
+	cr0 = rget("cr0real");
+	if((cr0 & Cr0Pg) == 0)
+		return translateflat;
+	efer = rget("efer");
+	if((efer & EferLme) != 0)
+		return translate64;
+	cr4 = rget("cr4real");
+	*cr4p = cr4;
+	if((cr4 & Cr4Pae) != 0)
+		return translatepae;
+	return translate32;
+}
+
+static void
+vmemread0(void *aux)
+{
+	VMemReq *req;
+	uintptr va, pa, n, ok, pok, cr4;
+	void *v;
+	uintptr (*trans)(uintptr, uintptr *, uintptr);
+	uchar *p;
+	
+	req = aux;
+	va = req->va;
+	n = req->len;
+	p = req->buf;
+	trans = translator(&cr4);
+	while(n > 0){
+		ok = trans(va, &pa, cr4);
+		if(ok == 0) break;
+		if(ok > n) ok = n;
+		v = gptr(pa, 1);
+		if(v == nil) break;
+		pok = gavail(v);
+		if(ok > pok) ok = pok;
+		memmove(p, v, ok);
+		n -= ok;
+		p += ok;
+		va += ok;
+	}
+	req->rc = req->len - n;
+	qunlock(req);
+}
+
+uintptr
+vmemread(void *buf, uintptr len, uintptr va)
+{
+	VMemReq req;
+	
+	memset(&req, 0, sizeof(VMemReq));
+	req.buf = buf;
+	req.len = len;
+	req.va = va;
+	qlock(&req);
+	sendnotif(vmemread0, &req);
+	qlock(&req);
+	return req.rc;
+}