Re: [Xen-devel] Re: [Xen-changelog] [xen-unstable] Clean up handling of IS_PRIV_FOR() and rcu_[un]lock_domain().

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>]

Keir Fraser, le Sat 05 Apr 2008 17:31:39 +0100, a écrit :
> On 5/4/08 15:28, "Samuel Thibault" <samuel.thibault@xxxxxxxxxxxxx> wrote:
> 
> >> They were all fine, except there was one inexplicable check of 
> >> IS_PRIV_FOR()
> >> in bind_interdomain() which I nuked. It was so bizarre that I assumed you
> >> must have put it there for a reason, and this would be one that you'd
> >> complain about.
> > 
> > I'm now complaining :)
> > 
> > The bind_interdomain() trick is needed for the ioreq events channel:
> > when it gets installed, it is supposed to be between the HVM domain and
> > dom0 (the stub domain doesn't exist anyway).  The meaning of the test is
> > hence to allow the stub domain to hijack that event channel (because it
> > has privileges on the remote domain).
> 
> The hack kind of sucks. :-) Add a new hvm_param to indicate the device model
> domain. Default it to zero, and if it becomes set to some other value (by
> the stub domain itself, when it starts) then re-create the event-channel
> port with new remote domid.



hvm: Add HVM_PARAM_DM_DOMAIN to let ioreq events go to a stub domain
instead of dom0.

Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>

diff -r fec296bcfd21 tools/ioemu/hw/xen_machine_fv.c
--- a/tools/ioemu/hw/xen_machine_fv.c   Fri Apr 11 09:57:06 2008 +0100
+++ b/tools/ioemu/hw/xen_machine_fv.c   Fri Apr 11 15:27:36 2008 +0100
@@ -205,6 +205,7 @@ static void xen_init_fv(uint64_t ram_siz
     }
 #endif
 
+    xc_set_hvm_param(xc_handle, domid, HVM_PARAM_DM_DOMAIN, DOMID_SELF);
     xc_get_hvm_param(xc_handle, domid, HVM_PARAM_IOREQ_PFN, &ioreq_pfn);
     fprintf(logfile, "shared page at pfn %lx\n", ioreq_pfn);
     shared_page = xc_map_foreign_range(xc_handle, domid, XC_PAGE_SIZE,
diff -r fec296bcfd21 xen/arch/ia64/vmx/vmx_hypercall.c
--- a/xen/arch/ia64/vmx/vmx_hypercall.c Fri Apr 11 09:57:06 2008 +0100
+++ b/xen/arch/ia64/vmx/vmx_hypercall.c Fri Apr 11 15:27:36 2008 +0100
@@ -165,6 +165,23 @@ do_hvm_op(unsigned long op, XEN_GUEST_HA
                 iorp = &d->arch.hvm_domain.buf_pioreq;
                 rc = vmx_set_ioreq_page(d, iorp, a.value);
                 break;
+            case HVM_PARAM_DM_DOMAIN:
+                /* Recreate ioreq event channels */
+                if (a.value == DOMID_SELF)
+                    a.value = current->domain->domain_id;
+                iorp = &d->arch.hvm_domain.ioreq;
+                for_each_vcpu ( d, v ) {
+                    rc = alloc_unbound_xen_event_channel(v, a.value);
+                    if (rc < 0)
+                        goto param_fail;
+                    free_xen_event_channel(v, v->arch.arch_vmx.xen_port);
+                    v->arch.arch_vmx.xen_port = rc;
+                    spin_lock(&iorp->lock);
+                    if (iorp->va != NULL)
+                        get_ioreq(v)->vp_eport = rc;
+                    spin_unlock(&iorp->lock);
+                }
+                break;
             default:
                 /* nothing */
                 break;
diff -r fec296bcfd21 xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Fri Apr 11 09:57:06 2008 +0100
+++ b/xen/arch/x86/hvm/hvm.c    Fri Apr 11 15:27:36 2008 +0100
@@ -2239,6 +2239,23 @@ long do_hvm_op(unsigned long op, XEN_GUE
 
                 domain_unpause(d);
                 break;
+            case HVM_PARAM_DM_DOMAIN:
+                /* Recreate ioreq event channels */
+                if (a.value == DOMID_SELF)
+                    a.value = current->domain->domain_id;
+                iorp = &d->arch.hvm_domain.ioreq;
+                for_each_vcpu ( d, v ) {
+                    rc = alloc_unbound_xen_event_channel(v, a.value);
+                    if (rc < 0)
+                        goto param_fail;
+                    free_xen_event_channel(v, v->arch.hvm_vcpu.xen_port);
+                    v->arch.hvm_vcpu.xen_port = rc;
+                    spin_lock(&iorp->lock);
+                    if (iorp->va != NULL)
+                        get_ioreq(v)->vp_eport = rc;
+                    spin_unlock(&iorp->lock);
+                }
+                break;
             }
             d->arch.hvm_domain.params[a.index] = a.value;
             rc = 0;
diff -r fec296bcfd21 xen/include/public/hvm/params.h
--- a/xen/include/public/hvm/params.h   Fri Apr 11 09:57:06 2008 +0100
+++ b/xen/include/public/hvm/params.h   Fri Apr 11 15:27:36 2008 +0100
@@ -85,6 +85,9 @@
 #define HVM_PARAM_HPET_ENABLED 11
 #define HVM_PARAM_IDENT_PT     12
 
-#define HVM_NR_PARAMS          13
+/* Device Model domain, defaults to 0 */
+#define HVM_PARAM_DM_DOMAIN    13
+
+#define HVM_NR_PARAMS          14
 
 #endif /* __XEN_PUBLIC_HVM_PARAMS_H__ */

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