diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-05-23 12:56:59 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-05-24 14:23:01 -0400 |
| commit | 5842f5768599094758931b74190cdf93641a8e35 (patch) | |
| tree | 32eb4c87399c9cc60eabace7dd098fd660ca5eaa /drivers/tty/hvc | |
| parent | a32c88b9386ce3df87f28dd46bdc3776cd6edf75 (diff) | |
xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness.
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.
CC: stable@kernel.org
Fixes-Oracle-Bug: 14091238
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/tty/hvc')
| -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 3277f0eec4a..944eaeb8e0c 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); |