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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5 2/3] x86/hvm: introduce functions for HVMOP_get/set_param allowance checks
Some parameters can only (validly) be set once. Some should not be set
by a guest for its own domain, and others must not be set since they
require the domain to be paused. Consolidate these checks, along with
the XSM check, in a new hvm_allow_set_param() function for clarity.
Also, introduce hvm_allow_get_param() for similar reasons.
NOTE: This patch leaves the guest accessible parameter checks as
black-lists and does not make any changes to which parameters
can be accessed. A subsequent patch will tighten up these
checks by changing from black-lists to white-lists.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/hvm/hvm.c | 136 ++++++++++++++++++++++++++++++------------------
1 file changed, 84 insertions(+), 52 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index dcbb11e..6be1c7f 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -5615,6 +5615,55 @@ static int hvmop_set_evtchn_upcall_vector(
return 0;
}
+static int hvm_allow_set_param(struct domain *d,
+ const struct xen_hvm_param *a)
+{
+ uint64_t value = d->arch.hvm_domain.params[a->index];
+ int rc;
+
+ rc = xsm_hvm_param(XSM_TARGET, d, HVMOP_set_param);
+ if ( rc )
+ return rc;
+
+ switch ( a->index )
+ {
+ /*
+ * The following parameters must not be set by the guest
+ * since the domain may need to be paused.
+ */
+ case HVM_PARAM_IDENT_PT:
+ case HVM_PARAM_DM_DOMAIN:
+ case HVM_PARAM_ACPI_S_STATE:
+ /* The following parameters should not be set by the guest. */
+ case HVM_PARAM_VIRIDIAN:
+ case HVM_PARAM_IOREQ_SERVER_PFN:
+ case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
+ if ( d == current->domain )
+ rc = -EPERM;
+ break;
+ default:
+ break;
+ }
+
+ if ( rc )
+ return rc;
+
+ switch ( a->index )
+ {
+ /* The following parameters should only be changed once. */
+ case HVM_PARAM_VIRIDIAN:
+ case HVM_PARAM_IOREQ_SERVER_PFN:
+ case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
+ if ( value != 0 && a->value != value )
+ rc = -EEXIST;
+ break;
+ default:
+ break;
+ }
+
+ return rc;
+}
+
static int hvmop_set_param(
XEN_GUEST_HANDLE_PARAM(xen_hvm_param_t) arg)
{
@@ -5639,7 +5688,7 @@ static int hvmop_set_param(
(is_pvh_domain(d) && (a.index != HVM_PARAM_CALLBACK_IRQ)) )
goto out;
- rc = xsm_hvm_param(XSM_TARGET, d, HVMOP_set_param);
+ rc = hvm_allow_set_param(d, &a);
if ( rc )
goto out;
@@ -5654,31 +5703,11 @@ static int hvmop_set_param(
rc = -EINVAL;
break;
case HVM_PARAM_VIRIDIAN:
- /* This should only ever be set once by the tools and read by the
guest. */
- rc = -EPERM;
- if ( d == curr_d )
- break;
-
- if ( a.value != d->arch.hvm_domain.params[a.index] )
- {
- rc = -EEXIST;
- if ( d->arch.hvm_domain.params[a.index] != 0 )
- break;
-
+ if ( (a.value & ~HVMPV_feature_mask) ||
+ !(a.value & HVMPV_base_freq) )
rc = -EINVAL;
- if ( (a.value & ~HVMPV_feature_mask) ||
- !(a.value & HVMPV_base_freq) )
- break;
- }
-
- rc = 0;
break;
case HVM_PARAM_IDENT_PT:
- /* Not reflexive, as we must domain_pause(). */
- rc = -EPERM;
- if ( d == curr_d )
- break;
-
rc = -EINVAL;
if ( d->arch.hvm_domain.params[a.index] != 0 )
break;
@@ -5706,22 +5735,12 @@ static int hvmop_set_param(
domctl_lock_release();
break;
case HVM_PARAM_DM_DOMAIN:
- /* Not reflexive, as we may need to domain_pause(). */
- rc = -EPERM;
- if ( d == curr_d )
- break;
-
if ( a.value == DOMID_SELF )
a.value = curr_d->domain_id;
rc = hvm_set_dm_domain(d, a.value);
break;
case HVM_PARAM_ACPI_S_STATE:
- /* Not reflexive, as we must domain_pause(). */
- rc = -EPERM;
- if ( d == curr_d )
- break;
-
rc = 0;
if ( a.value == 3 )
hvm_s3_suspend(d);
@@ -5773,22 +5792,12 @@ static int hvmop_set_param(
rc = -EINVAL;
break;
case HVM_PARAM_IOREQ_SERVER_PFN:
- if ( d == curr_d )
- {
- rc = -EPERM;
- break;
- }
d->arch.hvm_domain.ioreq_gmfn.base = a.value;
break;
case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
{
unsigned int i;
- if ( d == curr_d )
- {
- rc = -EPERM;
- break;
- }
if ( a.value == 0 ||
a.value > sizeof(d->arch.hvm_domain.ioreq_gmfn.mask) * 8 )
{
@@ -5815,10 +5824,40 @@ static int hvmop_set_param(
return rc;
}
+static int hvm_allow_get_param(struct domain *d,
+ const struct xen_hvm_param *a)
+{
+ int rc;
+
+ rc = xsm_hvm_param(XSM_TARGET, d, HVMOP_get_param);
+ if ( rc )
+ return rc;
+
+ switch ( a->index )
+ {
+ /*
+ * The following parameters must not be read by the guest
+ * since the domain may need to be paused.
+ */
+ case HVM_PARAM_IOREQ_PFN:
+ case HVM_PARAM_BUFIOREQ_PFN:
+ case HVM_PARAM_BUFIOREQ_EVTCHN:
+ /* The following parameters should not be read by the guest. */
+ case HVM_PARAM_IOREQ_SERVER_PFN:
+ case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
+ if ( d == current->domain )
+ rc = -EPERM;
+ break;
+ default:
+ break;
+ }
+
+ return rc;
+}
+
static int hvmop_get_param(
XEN_GUEST_HANDLE_PARAM(xen_hvm_param_t) arg)
{
- struct domain *curr_d = current->domain;
struct xen_hvm_param a;
struct domain *d;
int rc;
@@ -5838,7 +5877,7 @@ static int hvmop_get_param(
(is_pvh_domain(d) && (a.index != HVM_PARAM_CALLBACK_IRQ)) )
goto out;
- rc = xsm_hvm_param(XSM_TARGET, d, HVMOP_get_param);
+ rc = hvm_allow_get_param(d, &a);
if ( rc )
goto out;
@@ -5847,13 +5886,6 @@ static int hvmop_get_param(
case HVM_PARAM_ACPI_S_STATE:
a.value = d->arch.hvm_domain.is_s3_suspended ? 3 : 0;
break;
- case HVM_PARAM_IOREQ_SERVER_PFN:
- case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
- if ( d == curr_d )
- {
- rc = -EPERM;
- goto out;
- }
case HVM_PARAM_IOREQ_PFN:
case HVM_PARAM_BUFIOREQ_PFN:
case HVM_PARAM_BUFIOREQ_EVTCHN:
--
1.7.10.4
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