Author: avg
Date: Wed Jan 18 14:14:00 2017
New Revision: 312382
URL: https://svnweb.freebsd.org/changeset/base/312382
Log:
MFC r310630: libkvm: support access to vmm guest memory, allow writes to
fwmem and vmm
Sponsored by: Panzura
Modified:
stable/10/include/paths.h
stable/10/lib/libkvm/kvm.c
stable/10/lib/libkvm/kvm_private.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/include/paths.h
==============================================================================
--- stable/10/include/paths.h Wed Jan 18 14:13:28 2017 (r312381)
+++ stable/10/include/paths.h Wed Jan 18 14:14:00 2017 (r312382)
@@ -98,6 +98,7 @@
#define _PATH_VARDB "/var/db/"
#define _PATH_VARRUN "/var/run/"
#define _PATH_VARTMP "/var/tmp/"
+#define _PATH_DEVVMM "/dev/vmm/"
#define _PATH_YP "/var/yp/"
#define _PATH_UUCPLOCK "/var/spool/lock/"
Modified: stable/10/lib/libkvm/kvm.c
==============================================================================
--- stable/10/lib/libkvm/kvm.c Wed Jan 18 14:13:28 2017 (r312381)
+++ stable/10/lib/libkvm/kvm.c Wed Jan 18 14:14:00 2017 (r312382)
@@ -198,8 +198,10 @@ _kvm_open(kvm_t *kd, const char *uf, con
return (kd);
}
}
+
/*
- * This is a crash dump.
+ * This is either a crash dump or a remote live system with its physical
+ * memory fully accessible via a special device.
* Initialize the virtual address translation machinery,
* but first setup the namelist fd.
*/
@@ -207,8 +209,11 @@ _kvm_open(kvm_t *kd, const char *uf, con
_kvm_syserr(kd, kd->program, "%s", uf);
goto failed;
}
- if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0)
+ if (strncmp(mf, _PATH_FWMEM, strlen(_PATH_FWMEM)) == 0 ||
+ strncmp(mf, _PATH_DEVVMM, strlen(_PATH_DEVVMM)) == 0) {
kd->rawdump = 1;
+ kd->writable = 1;
+ }
if (_kvm_initvtop(kd) < 0)
goto failed;
return (kd);
@@ -557,6 +562,15 @@ ssize_t
kvm_write(kvm_t *kd, u_long kva, const void *buf, size_t len)
{
int cc;
+ ssize_t cw;
+ off_t pa;
+ const char *cp;
+
+ if (!ISALIVE(kd) && !kd->writable) {
+ _kvm_err(kd, kd->program,
+ "kvm_write not implemented for dead kernels");
+ return (-1);
+ }
if (ISALIVE(kd)) {
/*
@@ -574,10 +588,36 @@ kvm_write(kvm_t *kd, u_long kva, const v
} else if ((size_t)cc < len)
_kvm_err(kd, kd->program, "short write");
return (cc);
- } else {
- _kvm_err(kd, kd->program,
- "kvm_write not implemented for dead kernels");
- return (-1);
}
- /* NOTREACHED */
+
+ cp = buf;
+ while (len > 0) {
+ cc = _kvm_kvatop(kd, kva, &pa);
+ if (cc == 0)
+ return (-1);
+ if (cc > (ssize_t)len)
+ cc = len;
+ errno = 0;
+ if (lseek(kd->pmfd, pa, 0) == -1 && errno != 0) {
+ _kvm_syserr(kd, 0, _PATH_MEM);
+ break;
+ }
+ cw = write(kd->pmfd, cp, cc);
+ if (cw < 0) {
+ _kvm_syserr(kd, kd->program, "kvm_write");
+ break;
+ }
+ /*
+ * If ka_kvatop returns a bogus value or our core file is
+ * truncated, we might wind up seeking beyond the end of the
+ * core file in which case the read will return 0 (EOF).
+ */
+ if (cw == 0)
+ break;
+ cp += cw;
+ kva += cw;
+ len -= cw;
+ }
+
+ return (cp - (char *)buf);
}
Modified: stable/10/lib/libkvm/kvm_private.h
==============================================================================
--- stable/10/lib/libkvm/kvm_private.h Wed Jan 18 14:13:28 2017
(r312381)
+++ stable/10/lib/libkvm/kvm_private.h Wed Jan 18 14:14:00 2017
(r312382)
@@ -62,6 +62,7 @@ struct __kvm {
*/
struct vmstate *vmst;
int rawdump; /* raw dump format */
+ int writable; /* physical memory is writable */
int vnet_initialized; /* vnet fields set up */
uintptr_t vnet_start; /* start of kernel's vnet region */
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