Re: ARM: access to iomem and HW IRQ

[Eric Trudeau <etrudeau@broadcom.com>]

> -----Original Message-----
> From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com]
> Sent: Thursday, February 27, 2014 8:16 AM
> To: Dario Faggioli
> Cc: Viktor Kleinik; xen-devel@lists.xen.org; Arianna Avanzini; Stefano Stabellini;
> Julien Grall; Eric Trudeau
> Subject: Re: [Xen-devel] ARM: access to iomem and HW IRQ
> 
> On Thu, 27 Feb 2014, Dario Faggioli wrote:
> > On mer, 2014-02-26 at 15:43 +0000, Viktor Kleinik wrote:
> > > Hi all,
> > >
> > Hi,
> >
> > > Does anyone knows something about future plans to implement
> > > xc_domain_memory_mapping/XEN_DOMCTL_memory_mapping and
> > > xc_physdev_map_pirq/PHYSDEVOP_map_pirq calls for ARM?
> > >
> > I think Arianna is working on an implementation of the former
> > (XEN_DOMCTL_memory_mapping), and she should be sending patches to this
> > list soon, isn't it so, Arianna?
> 
> Eric Trudeau did some work in the area too:
> 
> http://marc.info/?l=xen-devel&m=137338996422503
> http://marc.info/?l=xen-devel&m=137365750318936

I checked our repo and the route IRQ changes to DomUs in the second patch URL Stefano provided below are up-to-date with what we have been using on our platforms.  We made no further changes after that patch, i.e. we left the 100 msec max wait for a domain to finish an ISR when destroying it.

We also added support for a DomU to map in I/O memory with the iomem configuration parameter.  Unfortunately, I don't have time to provide an official patch on recent Xen upstream code due to time constraints, but below is a patch based on last October, :( , commit d70d87d2ccf93e3d5302bb034c0a1ae1d6fc1d29.
I hope this is helpful, because that is the best I can do at this time.

-----------------

tools/libxl/libxl_create.c |  5 +++--
 xen/arch/arm/domctl.c      | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 1b320d3..53ed52e 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -976,8 +976,9 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__multidev *multidev,
         LOG(DEBUG, "dom%d iomem %"PRIx64"-%"PRIx64,
             domid, io->start, io->start + io->number - 1);
 
-        ret = xc_domain_iomem_permission(CTX->xch, domid,
-                                          io->start, io->number, 1);
+        ret = xc_domain_memory_mapping(CTX->xch, domid,
+                                       io->start, io->start,
+                                       io->number, 1);
         if (ret < 0) {
             LOGE(ERROR,
                  "failed give dom%d access to iomem range %"PRIx64"-%"PRIx64,
diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
index 851ee40..222aac9 100644
--- a/xen/arch/arm/domctl.c
+++ b/xen/arch/arm/domctl.c
@@ -10,11 +10,83 @@
 #include <xen/errno.h>
 #include <xen/sched.h>
 #include <public/domctl.h>
+#include <xen/iocap.h>
+#include <xsm/xsm.h>
+#include <xen/paging.h>
+#include <xen/guest_access.h>
 
 long arch_do_domctl(struct xen_domctl *domctl, struct domain *d,
                     XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
 {
-    return -ENOSYS;
+    long ret = 0;
+    bool_t copyback = 0;
+
+    switch ( domctl->cmd )
+    {
+    case XEN_DOMCTL_memory_mapping:
+    {
+        unsigned long gfn = domctl->u.memory_mapping.first_gfn;
+        unsigned long mfn = domctl->u.memory_mapping.first_mfn;
+        unsigned long nr_mfns = domctl->u.memory_mapping.nr_mfns;
+        int add = domctl->u.memory_mapping.add_mapping;
+
+        /* removing i/o memory is not implemented yet */
+        if (!add) {
+            ret = -ENOSYS;
+            break;
+        }
+        ret = -EINVAL;
+        if ( (mfn + nr_mfns - 1) < mfn || /* wrap? */
+             /* x86 checks wrap based on paddr_bits which is not implemented on ARM? */
+             /* ((mfn | (mfn + nr_mfns - 1)) >> (paddr_bits - PAGE_SHIFT)) || */
+             (gfn + nr_mfns - 1) < gfn ) /* wrap? */
+            break;
+
+        ret = -EPERM;
+        if ( current->domain->domain_id != 0 )
+            break;
+
+        ret = xsm_iomem_mapping(XSM_HOOK, d, mfn, mfn + nr_mfns - 1, add);
+        if ( ret )
+            break;
+
+        if ( add )
+        {
+            printk(XENLOG_G_INFO
+                   "memory_map:add: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+                   d->domain_id, gfn, mfn, nr_mfns);
+
+            ret = iomem_permit_access(d, mfn, mfn + nr_mfns - 1);
+            if ( !ret && paging_mode_translate(d) )
+            {
+                ret = map_mmio_regions(d, gfn << PAGE_SHIFT,
+                                       (gfn + nr_mfns) << PAGE_SHIFT,
+                                       mfn << PAGE_SHIFT);
+                if ( ret )
+                {
+                    printk(XENLOG_G_WARNING
+                           "memory_map:fail: dom%d gfn=%lx mfn=%lx nr=%lx\n",
+                           d->domain_id, gfn, mfn, nr_mfns);
+                    if ( iomem_deny_access(d, mfn, mfn + nr_mfns - 1) &&
+                         is_hardware_domain(current->domain) )
+                        printk(XENLOG_ERR
+                               "memory_map: failed to deny dom%d access to [%lx,%lx]\n",
+                               d->domain_id, mfn, mfn + nr_mfns - 1);
+                }
+            }
+        }
+    }
+    break;
+
+    default:
+        ret = -ENOSYS;
+        break;
+    }
+
+    if ( copyback && __copy_to_guest(u_domctl, domctl, 1) )
+        ret = -EFAULT;
+
+    return ret;
 }
 
 void arch_get_info_guest(struct vcpu *v, vcpu_guest_context_u c)