diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-05-23 12:56:59 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-22 11:36:54 -0700 |
| commit | 2da19ffd395d0fdba4ccbc4a3c751554059d4aa3 (patch) | |
| tree | e17c3f199c7cb570c8200c37741f772ea16a506c /drivers | |
| parent | 85fc3e3eba89272acb005f320ccafa0588a48f49 (diff) | |
xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness.
commit 5842f5768599094758931b74190cdf93641a8e35 upstream.
We need to make sure that those parameters are setup to be correct.
As such the value of 0 is deemed invalid and we find that we
bail out. The hypervisor sets by default all of them to be zero
and when the hypercall is done does a simple:
a.value = d->arch.hvm_domain.params[a.index];
Which means that if the Xen toolstack forgot to setup the proper
HVM_PARAM_CONSOLE_EVTCHN (or the PFN one), we would get the
default value of 0 and use that.
Fixes-Oracle-Bug: 14091238
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/hvc/hvc_xen.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index 3277f0eec4a7..944eaeb8e0cf 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -214,14 +214,19 @@ static int xen_hvm_console_init(void) /* already configured */ if (info->intf != NULL) return 0; - + /* + * If the toolstack (or the hypervisor) hasn't set these values, the + * default value is 0. Even though mfn = 0 and evtchn = 0 are + * theoretically correct values, in practice they never are and they + * mean that a legacy toolstack hasn't initialized the pv console correctly. + */ r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v); - if (r < 0) + if (r < 0 || v == 0) goto err; info->evtchn = v; v = 0; r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v); - if (r < 0) + if (r < 0 || v == 0) goto err; mfn = v; info->intf = ioremap(mfn << PAGE_SHIFT, PAGE_SIZE); |