/*
* Returns: bytes remaining to be read. 0 => read all bytes, ie, success.
*/
int
xg_read_mem(uint64_t guestva, char *tobuf, int tobuf_len, uint64_t pgd3val)
{
struct xen_domctl_gdbsx_memio *iop = &domctl.u.gdbsx_guest_memio;
union {uint64_t llbuf8; char buf8[8];} u = {0};
int i, rc;
XGTRC("E:gva:%llx tobuf:%lx len:%d\n", guestva, tobuf, tobuf_len);
memset(&domctl.u, 0, sizeof(domctl.u));
iop->pgd3val = pgd3val;
iop->gva = guestva;
iop->uva = (uint64_aligned_t)((unsigned long)tobuf);
iop->len = tobuf_len;
iop->gwr = 0; /* not writing to guest */
if ( (rc = _domctl_hcall(XEN_DOMCTL_gdbsx_guestmemio, tobuf, tobuf_len)) )
{
XGTRC("ERROR: failed to read bytes. errno:%d rc:%d\n", errno, rc);
return tobuf_len;
}
for(i=0; i < XGMIN(8, tobuf_len); u.buf8[i]=tobuf[i], i++);
XGTRC("X:remain:%d buf8:0x%llx\n", iop->remain, u.llbuf8);
return iop->remain;
}
/*
* Single step the given vcpu. This is achieved by pausing all but given vcpus,
* setting the TF flag, let the domain run and pause, unpause all vcpus, and
* clear TF flag on given vcpu.
* Returns: 0 success
*/
int
xg_step(vcpuid_t which_vcpu, int guest_bitness)
{
int rc;
XGTRC("E:vcpu:%d\n", (int)which_vcpu);
if (_allbutone_vcpu(XEN_DOMCTL_gdbsx_pausevcpu, which_vcpu))
return 1;
if ((rc=_change_TF(which_vcpu, guest_bitness, 1)))
return rc;
XGTRC("unpausing domain\n");
/* now unpause the domain so our vcpu can execute */
if (_unpause_domain())
return 1;
/* wait for our vcpu to finish step */
_wait_domain_pause();
_allbutone_vcpu(XEN_DOMCTL_gdbsx_unpausevcpu, which_vcpu);
rc = _change_TF(which_vcpu, guest_bitness, 0);
return rc;
}
/*
* Resume the domain if no pending events. If there are pending events, like
* another vcpu in a BP, report it. Otherwise, continue, and wait till an
* event, like bp or user doing xm pause, occurs.
*
* Returns: vcpuid : if a vcpu hits a breakpoint or end of step
* -1 : either an error (msg printed on terminal), or non-bp
* event, like "xm pause domid", to enter debugger
*/
vcpuid_t
xg_resume_n_wait(int guest_bitness)
{
vcpuid_t vcpu;
XGTRC("E:\n");
assert(_domain_is_paused());
if ((vcpu=_vcpu_in_bp()) != -1) {
/* another vcpu in breakpoint. return it's id */
return vcpu;
}
XGTRC("unpausing domain\n");
if (_unpause_domain())
return -1;
/* now wait for domain to pause */
_wait_domain_pause();
/* check again if any vcpu in BP, or user thru "xm pause" */
vcpu = _vcpu_in_bp();
XGTRC("X:vcpu:%d\n", vcpu);
return vcpu;
}
/*
* Returns: 0 success
* -1 failure, errno set.
*/
int
xg_init()
{
int flags, saved_errno;
XGTRC("E\n");
if ((_dom0_fd=open("/proc/xen/privcmd", O_RDWR)) == -1) {
perror("Failed to open /proc/xen/privcmd\n");
return -1;
}
/* Although we return the file handle as the 'xc handle' the API
* does not specify / guarentee that this integer is in fact
* a file handle. Thus we must take responsiblity to ensure
* it doesn't propagate (ie leak) outside the process (copied comment)*/
if ( (flags=fcntl(_dom0_fd, F_GETFD)) < 0 ) {
perror("Could not get file handle flags (F_GETFD)");
goto error;
}
flags |= FD_CLOEXEC;
if (fcntl(_dom0_fd, F_SETFD, flags) < 0) {
perror("Could not set file handle flags");
goto error;
}
XGTRC("X:fd:%d\n", _dom0_fd);
return _dom0_fd;
error:
XGTRC("X:Error: errno:%d\n", errno);
saved_errno = errno;
close(_dom0_fd);
errno = saved_errno;
return -1;
}
/*
* Returns: bytes that could not be written. 0 => wrote all bytes, ie, success.
*/
int
xg_write_mem(uint64_t guestva, char *frombuf, int buflen, uint64_t pgd3val)
{
struct xen_domctl_gdbsx_memio *iop = &domctl.u.gdbsx_guest_memio;
union {uint64_t llbuf8; char buf8[8];} u = {0};
int i, rc;
for(i=0; i < XGMIN(8, buflen); u.buf8[i]=frombuf[i], i++);
XGTRC("E:gva:%llx frombuf:%lx len:%d buf8:0x%llx\n", guestva, frombuf,
buflen, u.llbuf8);
memset(&domctl.u, 0, sizeof(domctl.u));
iop->pgd3val = pgd3val;
iop->gva = guestva;
iop->uva = (uint64_aligned_t)((unsigned long)frombuf);
iop->len = buflen;
iop->gwr = 1; /* writing to guest */
if ((rc=_domctl_hcall(XEN_DOMCTL_gdbsx_guestmemio, frombuf, buflen)))
{
XGERR("ERROR: failed to write bytes to %llx. errno:%d rc:%d\n",
guestva, errno, rc);
return buflen;
}
return iop->remain;
}
/*
* write registers for the given vcpu
* Returns: 0 success, 1 failure with errno
*/
int
xg_regs_write(regstype_t which_regs, vcpuid_t which_vcpu,
union xg_gdb_regs *regsp, int guest_bitness)
{
union vcpu_guest_context_any anyc;
struct cpu_user_regs_x86_32 *cr32p = &anyc.ctxt32.user_regs;
struct cpu_user_regs_x86_64 *cr64p = &anyc.ctxt64.user_regs;
struct xg_gdb_regs32 *r32p = ®sp->gregs_32;
struct xg_gdb_regs64 *r64p = ®sp->gregs_64;
int rc, sz = sizeof(anyc);
if (which_regs != XG_GPRS) {
errno = EINVAL;
XGERR("regs got: %d. Expected GPRS:%d\n", which_regs, XG_GPRS);
return 1;
}
if ((rc=_get_vcpu_ctxt(which_vcpu, &anyc)))
return rc;
if (guest_bitness == 32) {
if (_32bit_hyp || !_hvm_guest)
_cp_32gdb_to_32ctxt(r32p, cr32p);
else
_cp_32gdb_to_64ctxt(r32p, cr64p);
} else
_cp_64gdb_to_64ctxt(r64p, cr64p);
/* set vcpu context back */
if ((rc =_domctl_hcall(XEN_DOMCTL_setvcpucontext, &anyc, sz))) {
XGERR("Failed hcall to set vcpu ctxt. errno:%d\n", errno);
return rc;
}
XGTRC("X:vcpu:%d bitness:%d rc:%d\n", which_vcpu, guest_bitness, rc);
return rc;
}
/*
* read regs for a particular vcpu. For now only GPRs, no FPRs.
* Returns: 0 success, else failure with errno set
*/
int
xg_regs_read(regstype_t which_regs, vcpuid_t which_vcpu,
union xg_gdb_regs *regsp, int guest_bitness)
{
union vcpu_guest_context_any anyc;
struct cpu_user_regs_x86_32 *cr32p = &anyc.ctxt32.user_regs;
struct cpu_user_regs_x86_64 *cr64p = &anyc.ctxt64.user_regs;
struct xg_gdb_regs32 *r32p = ®sp->gregs_32;
struct xg_gdb_regs64 *r64p = ®sp->gregs_64;
int rc;
if (which_regs != XG_GPRS) {
errno = EINVAL;
XGERR("regs got: %d. Expected GPRS:%d\n", which_regs, XG_GPRS);
return 1;
}
if ((rc=_get_vcpu_ctxt(which_vcpu, &anyc)))
return rc;
/* 64bit hyp: only 32bit PV returns 32bit context, all others 64bit.
* 32bit hyp: all contexts returned are 32bit */
if (guest_bitness == 32) {
if (_32bit_hyp || !_hvm_guest)
_cp_32ctxt_to_32gdb(cr32p, r32p);
else
_cp_64ctxt_to_32gdb(cr64p, r32p);
} else
_cp_64ctxt_to_64gdb(cr64p, r64p);
XGTRC("X:vcpu:%d bitness:%d rc:%d\n", which_vcpu, guest_bitness, rc);
return rc;
}
/*
* Change the TF flag for single step. TF = (setit ? 1 : 0);
* Returns: 0 Success
*/
static int
_change_TF(vcpuid_t which_vcpu, int guest_bitness, int setit)
{
union vcpu_guest_context_any anyc;
int sz = sizeof(anyc);
/* first try the MTF for hvm guest. otherwise do manually */
if (_hvm_guest) {
domctl.u.debug_op.vcpu = which_vcpu;
domctl.u.debug_op.op = setit ? XEN_DOMCTL_DEBUG_OP_SINGLE_STEP_ON :
XEN_DOMCTL_DEBUG_OP_SINGLE_STEP_OFF;
if (_domctl_hcall(XEN_DOMCTL_debug_op, NULL, 0) == 0) {
XGTRC("vcpu:%d:MTF success setit:%d\n", which_vcpu, setit);
return 0;
}
XGTRC("vcpu:%d:MTF failed. setit:%d\n", which_vcpu, setit);
}
memset(&anyc, 0, sz);
domctl.u.vcpucontext.vcpu = (uint16_t)which_vcpu;
set_xen_guest_handle(domctl.u.vcpucontext.ctxt, &anyc.ctxt);
if (_domctl_hcall(XEN_DOMCTL_getvcpucontext, &anyc, sz)) {
XGERR("Failed hcall to get vcpu ctxt for TF. errno:%d\n",errno);
return 1;
}
if (_32bit_hyp || (guest_bitness == 32 && !_hvm_guest)) {
if (setit)
anyc.ctxt32.user_regs.eflags |= X86_EFLAGS_TF;
else
anyc.ctxt32.user_regs.eflags &= ~X86_EFLAGS_TF;
} else {
if (setit)
anyc.ctxt64.user_regs.rflags |= X86_EFLAGS_TF;
else
anyc.ctxt64.user_regs.rflags &= ~X86_EFLAGS_TF;
}
if (_domctl_hcall(XEN_DOMCTL_setvcpucontext, &anyc, sz)) {
XGERR("Failed hcall to set vcpu ctxt for TF. errno:%d\n",errno);
return 1;
}
return 0;
}
/*
* Returns : 0 success.
* 1 error, with errno set (hopefully :))
*/
static int
_wait_domain_pause(void)
{
int dom_paused;
struct timespec ts={0, 10*1000*1000};
XGTRC("E:\n");
do {
dom_paused = _domain_is_paused();
nanosleep(&ts, NULL);
} while(!dom_paused);
return 0;
}
/*
* Attach to the given domid for debugging.
* Returns: max vcpu id : Success
* -1 : Failure
*/
int
xg_attach(int domid, int guest_bitness)
{
XGTRC("E:domid:%d\n", domid);
_dom_id = domctl.domain = domid;
domctl.interface_version = XEN_DOMCTL_INTERFACE_VERSION;
if (mlock(&domctl, sizeof(domctl))) {
XGERR("Unable to pin domctl in memory. errno:%d\n", errno);
return -1;
}
if (_check_hyp(guest_bitness))
return -1;
if (_domctl_hcall(XEN_DOMCTL_pausedomain, NULL, 0)) {
XGERR("Unable to pause domain:%d\n", _dom_id);
return -1;
}
memset(&domctl.u, 0, sizeof(domctl.u));
domctl.u.setdebugging.enable = 1;
if (_domctl_hcall(XEN_DOMCTL_setdebugging, NULL, 0)) {
XGERR("Unable to set domain to debug mode: errno:%d\n", errno);
_unpause_domain();
return -1;
}
memset(&domctl.u, 0, sizeof(domctl.u));
if (_domctl_hcall(XEN_DOMCTL_getdomaininfo, NULL, 0)) {
XGERR("Unable to get domain info: domid:%d errno:%d\n",
domid, errno);
_unpause_domain();
return -1;
}
if (!_domain_ok(&domctl.u.getdomaininfo)) {
_unpause_domain();
return -1;
}
_max_vcpu_id = domctl.u.getdomaininfo.max_vcpu_id;
_hvm_guest = (domctl.u.getdomaininfo.flags & XEN_DOMINF_hvm_guest);
_pvh_guest = (domctl.u.getdomaininfo.flags & XEN_DOMINF_pvh_guest);
return _max_vcpu_id;
}
/*
* Make sure we are running on hyp enabled for gdbsx. Also, note whether
* its 32bit. Fail if user typed 64bit for guest in case of 32bit hyp.
*
* RETURNS: 0 : everything OK.
*/
static int
_check_hyp(int guest_bitness)
{
xen_capabilities_info_t xen_caps = "";
privcmd_hypercall_t hypercall;
int rc;
/*
* Try to unpause an invalid vcpu. If hypervisor supports gdbsx then
* this should fail with an error other than ENOSYS.
*/
domctl.u.gdbsx_pauseunp_vcpu.vcpu = ~0u;
(void)_domctl_hcall(XEN_DOMCTL_gdbsx_unpausevcpu, NULL, 0);
if (errno == ENOSYS) {
XGERR("Hyp is NOT enabled for gdbsx\n");
return -1;
}
if (mlock(&xen_caps, sizeof(xen_caps))) {
XGERR("Unable to pin xen_caps in memory. errno:%d\n", errno);
return -1;
}
memset(&xen_caps, 0, sizeof(xen_caps));
hypercall.op = __HYPERVISOR_xen_version;
hypercall.arg[0] = (unsigned long)XENVER_capabilities;
hypercall.arg[1] = (unsigned long)&xen_caps;
rc = ioctl(_dom0_fd, IOCTL_PRIVCMD_HYPERCALL, &hypercall);
munlock(&xen_caps, sizeof(xen_caps));
XGTRC("XENCAPS:%s\n", xen_caps);
if (rc != 0) {
XGERR("Failed xen_version hcall. errno:%d\n", errno);
return -1;
}
_32bit_hyp = (strstr(xen_caps, "x86_64") == NULL);
if (_32bit_hyp && guest_bitness !=32) {
XGERR("32bit hyp can only run 32bit guests\n");
return -1;
}
return 0;
}
