[Xen-devel,v2,3/4] xen/arm: clean and invalidate all guest caches by VMID after domain build.

Message ID 1391616235-22703-3-git-send-email-ian.campbell@citrix.com
State New
Headers show

Commit Message

Ian Campbell Feb. 5, 2014, 4:03 p.m.
Guests are initially started with caches disabled and so we need to make sure
they see consistent data in RAM (requiring a cache clean) but also that they
do not have old stale data suddenly appear in the caches when they enable
their caches (requiring the invalidate).

This can be split into two halves. First we must flush each page as it is
allocated to the guest. It is not sufficient to do the flush at scrub time
since this will miss pages which are ballooned out by the guest (where the
guest must scrub if it cares about not leaking the pagecontent). We need to
clean as well as invalidate to make sure that any scrubbing which has occured
gets committed to real RAM. To achieve this add a new cacheflush_page function,
which is a stub on x86.

Secondly we need to flush anything which the domain builder touches, which we
do via a new domctl.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: jbeulich@suse.com
Cc: keir@xen.org
Cc: ian.jackson@eu.citrix.com
--
v3:
    s/cacheflush_page/sync_page_to_ram/

    xc interface takes a length instead of an end

    make the domctl range inclusive.

    make xc interface internal -- it isn't needed from libxl in the current
    design and it is easier to expose an interface in the future than to hide
    it.

v2:
   Switch to cleaning at page allocation time + explicit flushing of the
   regions which the toolstack touches.

   Add XSM for new domctl.

   New domctl restricts the amount of space it is willing to flush, to avoid
   thinking about preemption.
---
 tools/libxc/xc_dom_boot.c           |    4 ++++
 tools/libxc/xc_dom_core.c           |    2 ++
 tools/libxc/xc_domain.c             |   10 ++++++++++
 tools/libxc/xc_private.c            |    2 ++
 tools/libxc/xc_private.h            |    3 +++
 tools/libxc/xenctrl.h               |    1 -
 xen/arch/arm/domctl.c               |   14 ++++++++++++++
 xen/arch/arm/mm.c                   |    9 +++++++++
 xen/arch/arm/p2m.c                  |   25 +++++++++++++++++++++++++
 xen/common/page_alloc.c             |    5 +++++
 xen/include/asm-arm/p2m.h           |    3 +++
 xen/include/asm-arm/page.h          |    3 +++
 xen/include/asm-x86/page.h          |    3 +++
 xen/include/public/domctl.h         |   13 +++++++++++++
 xen/xsm/flask/hooks.c               |    3 +++
 xen/xsm/flask/policy/access_vectors |    2 ++
 16 files changed, 101 insertions(+), 1 deletion(-)

Comments

Ian Campbell Feb. 6, 2014, 10:28 a.m. | #1
On Thu, 2014-02-06 at 09:53 +0000, Jan Beulich wrote:
> >>> On 05.02.14 at 17:03, Ian Campbell <ian.campbell@citrix.com> wrote:
> > --- a/tools/libxc/xc_domain.c
> > +++ b/tools/libxc/xc_domain.c
> > @@ -48,6 +48,16 @@ int xc_domain_create(xc_interface *xch,
> >      return 0;
> >  }
> >  
> > +int xc_domain_cacheflush(xc_interface *xch, uint32_t domid,
> > +                         xen_pfn_t start_pfn, xen_pfn_t nr_pfns)
> > +{
> > +    DECLARE_DOMCTL;
> > +    domctl.cmd = XEN_DOMCTL_cacheflush;
> > +    domctl.domain = (domid_t)domid;
> > +    domctl.u.cacheflush.start_pfn = start_pfn;
> > +    domctl.u.cacheflush.end_pfn = start_pfn + nr_pfns;
> > +    return do_domctl(xch, &domctl);
> > +}
> 
> I'm confused - both in the overview mail and in domctl.h below
> you state the range to now be inclusive, yet neither here nor
> in the hypervisor changes this seems to actually be the case
> (unless the earlier "rename ..." patches now did more than just
> renaming - I didn't look at them).

Yes, I think I got myself confused.

I've actually now concluded that the start + nr interface should be
pushed down into the domctl layer too -- that seems to be the common
idiom and is less prone to confusion...

> 
> > --- a/tools/libxc/xenctrl.h
> > +++ b/tools/libxc/xenctrl.h
> > @@ -454,7 +454,6 @@ int xc_domain_create(xc_interface *xch,
> >                       uint32_t flags,
> >                       uint32_t *pdomid);
> >  
> > -
> >  /* Functions to produce a dump of a given domain
> >   *  xc_domain_dumpcore - produces a dump to a specified file
> >   *  xc_domain_dumpcore_via_callback - produces a dump, using a specified
> 
> Stray leftover change?

Yes, will remove.

Ian
Julien Grall Feb. 6, 2014, 2:26 p.m. | #2
Hi Ian,

On 05/02/14 16:03, Ian Campbell wrote:
> Guests are initially started with caches disabled and so we need to make sure
> they see consistent data in RAM (requiring a cache clean) but also that they
> do not have old stale data suddenly appear in the caches when they enable
> their caches (requiring the invalidate).
>
> This can be split into two halves. First we must flush each page as it is
> allocated to the guest. It is not sufficient to do the flush at scrub time
> since this will miss pages which are ballooned out by the guest (where the
> guest must scrub if it cares about not leaking the pagecontent). We need to
> clean as well as invalidate to make sure that any scrubbing which has occured
> gets committed to real RAM. To achieve this add a new cacheflush_page function,
> which is a stub on x86.
>
> Secondly we need to flush anything which the domain builder touches, which we
> do via a new domctl.

As I understand, there is no hypercall continuation so if a domain give 
a big range Xen will get stuck for a long time (no softirq will be 
handled on the current processor ...). Shall we at least use 
hypercall_create_continuation?
Ian Campbell Feb. 6, 2014, 2:29 p.m. | #3
On Thu, 2014-02-06 at 14:26 +0000, Julien Grall wrote:
> Hi Ian,
> 
> On 05/02/14 16:03, Ian Campbell wrote:
> > Guests are initially started with caches disabled and so we need to make sure
> > they see consistent data in RAM (requiring a cache clean) but also that they
> > do not have old stale data suddenly appear in the caches when they enable
> > their caches (requiring the invalidate).
> >
> > This can be split into two halves. First we must flush each page as it is
> > allocated to the guest. It is not sufficient to do the flush at scrub time
> > since this will miss pages which are ballooned out by the guest (where the
> > guest must scrub if it cares about not leaking the pagecontent). We need to
> > clean as well as invalidate to make sure that any scrubbing which has occured
> > gets committed to real RAM. To achieve this add a new cacheflush_page function,
> > which is a stub on x86.
> >
> > Secondly we need to flush anything which the domain builder touches, which we
> > do via a new domctl.
> 
> As I understand, there is no hypercall continuation so if a domain give 
> a big range Xen will get stuck for a long time (no softirq will be 
> handled on the current processor ...). Shall we at least use 
> hypercall_create_continuation?

The hypercall deliberately limits the allowable range to avoid this.

This was discussed with Jan in a previous iteration, the other places
which end up here have a similar property, perhaps as a future cleanup
they can all be made preemptable.

Ian.
Julien Grall Feb. 6, 2014, 2:48 p.m. | #4
On 05/02/14 16:03, Ian Campbell wrote:
    > +void sync_page_to_ram(unsigned long mfn)
> +{
> +    void *v = map_domain_page(mfn);
> +
> +    flush_xen_dcache_va_range(v, PAGE_SIZE);
> +

flush_xen_dcache_va_range uses DCCMVAC (for ARM32 bits), which only 
clean the cache.

Following your commit message, we might want to use DCCIMVAC.
Ian Campbell Feb. 6, 2014, 3:04 p.m. | #5
On Thu, 2014-02-06 at 14:48 +0000, Julien Grall wrote:
> 
> On 05/02/14 16:03, Ian Campbell wrote:
>     > +void sync_page_to_ram(unsigned long mfn)
> > +{
> > +    void *v = map_domain_page(mfn);
> > +
> > +    flush_xen_dcache_va_range(v, PAGE_SIZE);
> > +
> 
> flush_xen_dcache_va_range uses DCCMVAC (for ARM32 bits), which only 
> clean the cache.
> 
> Following your commit message, we might want to use DCCIMVAC.

Yes, I think you are right, I thought this function invalidated as well.

Ian.
Julien Grall Feb. 6, 2014, 3:41 p.m. | #6
On 06/02/14 15:04, Ian Campbell wrote:
> On Thu, 2014-02-06 at 14:48 +0000, Julien Grall wrote:
>>
>> On 05/02/14 16:03, Ian Campbell wrote:
>>      > +void sync_page_to_ram(unsigned long mfn)
>>> +{
>>> +    void *v = map_domain_page(mfn);
>>> +
>>> +    flush_xen_dcache_va_range(v, PAGE_SIZE);
>>> +
>>
>> flush_xen_dcache_va_range uses DCCMVAC (for ARM32 bits), which only
>> clean the cache.
>>
>> Following your commit message, we might want to use DCCIMVAC.
>
> Yes, I think you are right, I thought this function invalidated as well.

I was wondering if we can change the behaviour of 
flush_xen_dcache_va_range. Invalidate the cache should not harm the 
other call-site.
Ian Campbell Feb. 6, 2014, 3:45 p.m. | #7
On Thu, 2014-02-06 at 15:41 +0000, Julien Grall wrote:
> 
> On 06/02/14 15:04, Ian Campbell wrote:
> > On Thu, 2014-02-06 at 14:48 +0000, Julien Grall wrote:
> >>
> >> On 05/02/14 16:03, Ian Campbell wrote:
> >>      > +void sync_page_to_ram(unsigned long mfn)
> >>> +{
> >>> +    void *v = map_domain_page(mfn);
> >>> +
> >>> +    flush_xen_dcache_va_range(v, PAGE_SIZE);
> >>> +
> >>
> >> flush_xen_dcache_va_range uses DCCMVAC (for ARM32 bits), which only
> >> clean the cache.
> >>
> >> Following your commit message, we might want to use DCCIMVAC.
> >
> > Yes, I think you are right, I thought this function invalidated as well.
> 
> I was wondering if we can change the behaviour of 
> flush_xen_dcache_va_range. Invalidate the cache should not harm the 
> other call-site.

Perhaps, but not for 4.4.

I'm going to introduce clean_and_invalidate_xen_dcache and friends. 

Post 4.4 I'm also going to rename flush_xen_dcache_* to
clean_xen_dcache_* so I don't make this mistake again.

At that point we can consider where if anywhere moving from Clean to
Clean+Invalidate makes sense.

Ian.

Patch

diff --git a/tools/libxc/xc_dom_boot.c b/tools/libxc/xc_dom_boot.c
index 5a9cfc6..3d4d107 100644
--- a/tools/libxc/xc_dom_boot.c
+++ b/tools/libxc/xc_dom_boot.c
@@ -351,6 +351,10 @@  int xc_dom_gnttab_seed(xc_interface *xch, domid_t domid,
         return -1;
     }
 
+    /* Guest shouldn't really touch its grant table until it has
+     * enabled its caches. But lets be nice. */
+    xc_domain_cacheflush(xch, domid, gnttab_gmfn, 1);
+
     return 0;
 }
 
diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
index 77a4e64..b9d1015 100644
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -603,6 +603,8 @@  void xc_dom_unmap_one(struct xc_dom_image *dom, xen_pfn_t pfn)
         prev->next = phys->next;
     else
         dom->phys_pages = phys->next;
+
+    xc_domain_cacheflush(dom->xch, dom->guest_domid, phys->first, phys->count);
 }
 
 void xc_dom_unmap_all(struct xc_dom_image *dom)
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index c2fdd74..4e8e995 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -48,6 +48,16 @@  int xc_domain_create(xc_interface *xch,
     return 0;
 }
 
+int xc_domain_cacheflush(xc_interface *xch, uint32_t domid,
+                         xen_pfn_t start_pfn, xen_pfn_t nr_pfns)
+{
+    DECLARE_DOMCTL;
+    domctl.cmd = XEN_DOMCTL_cacheflush;
+    domctl.domain = (domid_t)domid;
+    domctl.u.cacheflush.start_pfn = start_pfn;
+    domctl.u.cacheflush.end_pfn = start_pfn + nr_pfns;
+    return do_domctl(xch, &domctl);
+}
 
 int xc_domain_pause(xc_interface *xch,
                     uint32_t domid)
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index 838fd21..33ed15b 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -628,6 +628,7 @@  int xc_copy_to_domain_page(xc_interface *xch,
         return -1;
     memcpy(vaddr, src_page, PAGE_SIZE);
     munmap(vaddr, PAGE_SIZE);
+    xc_domain_cacheflush(xch, domid, dst_pfn, 1);
     return 0;
 }
 
@@ -641,6 +642,7 @@  int xc_clear_domain_page(xc_interface *xch,
         return -1;
     memset(vaddr, 0, PAGE_SIZE);
     munmap(vaddr, PAGE_SIZE);
+    xc_domain_cacheflush(xch, domid, dst_pfn, 1);
     return 0;
 }
 
diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
index 92271c9..a610f0c 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -304,6 +304,9 @@  void bitmap_byte_to_64(uint64_t *lp, const uint8_t *bp, int nbits);
 /* Optionally flush file to disk and discard page cache */
 void discard_file_cache(xc_interface *xch, int fd, int flush);
 
+int xc_domain_cacheflush(xc_interface *xch, uint32_t domid,
+			 xen_pfn_t start_pfn, xen_pfn_t nr_pfns);
+
 #define MAX_MMU_UPDATES 1024
 struct xc_mmu {
     mmu_update_t updates[MAX_MMU_UPDATES];
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 13f816b..026239f 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -454,7 +454,6 @@  int xc_domain_create(xc_interface *xch,
                      uint32_t flags,
                      uint32_t *pdomid);
 
-
 /* Functions to produce a dump of a given domain
  *  xc_domain_dumpcore - produces a dump to a specified file
  *  xc_domain_dumpcore_via_callback - produces a dump, using a specified
diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
index 546e86b..8916e49 100644
--- a/xen/arch/arm/domctl.c
+++ b/xen/arch/arm/domctl.c
@@ -17,6 +17,20 @@  long arch_do_domctl(struct xen_domctl *domctl, struct domain *d,
 {
     switch ( domctl->cmd )
     {
+    case XEN_DOMCTL_cacheflush:
+    {
+        unsigned long s = domctl->u.cacheflush.start_pfn;
+        unsigned long e = domctl->u.cacheflush.end_pfn;
+
+        if ( e < s )
+            return -EINVAL;
+
+        if ( get_order_from_pages(e-s) > MAX_ORDER )
+            return -EINVAL;
+
+        return p2m_cache_flush(d, s, e);
+    }
+
     default:
         return subarch_do_domctl(domctl, d, u_domctl);
     }
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 2f48347..b33bef5 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -338,6 +338,15 @@  unsigned long domain_page_map_to_mfn(const void *va)
 }
 #endif
 
+void sync_page_to_ram(unsigned long mfn)
+{
+    void *v = map_domain_page(mfn);
+
+    flush_xen_dcache_va_range(v, PAGE_SIZE);
+
+    unmap_domain_page(v);
+}
+
 void __init arch_init_memory(void)
 {
     /*
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index a61edeb..86f13e9 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -8,6 +8,7 @@ 
 #include <asm/gic.h>
 #include <asm/event.h>
 #include <asm/hardirq.h>
+#include <asm/page.h>
 
 /* First level P2M is 2 consecutive pages */
 #define P2M_FIRST_ORDER 1
@@ -228,6 +229,7 @@  enum p2m_operation {
     ALLOCATE,
     REMOVE,
     RELINQUISH,
+    CACHEFLUSH,
 };
 
 static int apply_p2m_changes(struct domain *d,
@@ -381,6 +383,15 @@  static int apply_p2m_changes(struct domain *d,
                     count++;
                 }
                 break;
+
+            case CACHEFLUSH:
+                {
+                    if ( !pte.p2m.valid || !p2m_is_ram(pte.p2m.type) )
+                        break;
+
+                    sync_page_to_ram(pte.p2m.base);
+                }
+                break;
         }
 
         /* Preempt every 2MiB (mapped) or 32 MiB (unmapped) - arbitrary */
@@ -624,6 +635,20 @@  int relinquish_p2m_mapping(struct domain *d)
                               MATTR_MEM, p2m_invalid);
 }
 
+int p2m_cache_flush(struct domain *d, xen_pfn_t start_mfn, xen_pfn_t end_mfn)
+{
+    struct p2m_domain *p2m = &d->arch.p2m;
+
+    start_mfn = MAX(start_mfn, p2m->lowest_mapped_gfn);
+    end_mfn = MIN(end_mfn, p2m->max_mapped_gfn);
+
+    return apply_p2m_changes(d, CACHEFLUSH,
+                             pfn_to_paddr(start_mfn),
+                             pfn_to_paddr(end_mfn),
+                             pfn_to_paddr(INVALID_MFN),
+                             MATTR_MEM, p2m_invalid);
+}
+
 unsigned long gmfn_to_mfn(struct domain *d, unsigned long gpfn)
 {
     paddr_t p = p2m_lookup(d, pfn_to_paddr(gpfn), NULL);
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 5f484a2..c73c717 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -710,6 +710,11 @@  static struct page_info *alloc_heap_pages(
         /* Initialise fields which have other uses for free pages. */
         pg[i].u.inuse.type_info = 0;
         page_set_owner(&pg[i], NULL);
+
+        /* Ensure cache and RAM are consistent for platforms where the
+         * guest can control its own visibility of/through the cache.
+         */
+        sync_page_to_ram(page_to_mfn(&pg[i]));
     }
 
     spin_unlock(&heap_lock);
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index e9c884a..3b39c45 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -78,6 +78,9 @@  void p2m_load_VTTBR(struct domain *d);
 /* Look up the MFN corresponding to a domain's PFN. */
 paddr_t p2m_lookup(struct domain *d, paddr_t gpfn, p2m_type_t *t);
 
+/* Clean & invalidate caches corresponding to a region of guest address space */
+int p2m_cache_flush(struct domain *d, xen_pfn_t start_mfn, xen_pfn_t end_mfn);
+
 /* Setup p2m RAM mapping for domain d from start-end. */
 int p2m_populate_ram(struct domain *d, paddr_t start, paddr_t end);
 /* Map MMIO regions in the p2m: start_gaddr and end_gaddr is the range
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 670d4e7..67d64c9 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -253,6 +253,9 @@  static inline void flush_xen_dcache_va_range(void *p, unsigned long size)
             : : "r" (_p), "m" (*_p));                                   \
 } while (0)
 
+/* Flush the dcache for an entire page. */
+void sync_page_to_ram(unsigned long mfn);
+
 /* Print a walk of an arbitrary page table */
 void dump_pt_walk(lpae_t *table, paddr_t addr);
 
diff --git a/xen/include/asm-x86/page.h b/xen/include/asm-x86/page.h
index 7a46af5..abe35fb 100644
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -346,6 +346,9 @@  static inline uint32_t cacheattr_to_pte_flags(uint32_t cacheattr)
     return ((cacheattr & 4) << 5) | ((cacheattr & 3) << 3);
 }
 
+/* No cache maintenance required on x86 architecture. */
+static inline void sync_page_to_ram(unsigned long mfn) {}
+
 /* return true if permission increased */
 static inline bool_t
 perms_strictly_increased(uint32_t old_flags, uint32_t new_flags)
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 91f01fa..497e2a3 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -885,6 +885,17 @@  struct xen_domctl_set_max_evtchn {
 typedef struct xen_domctl_set_max_evtchn xen_domctl_set_max_evtchn_t;
 DEFINE_XEN_GUEST_HANDLE(xen_domctl_set_max_evtchn_t);
 
+/*
+ * ARM: Clean and invalidate caches associated with given region of
+ * guest memory.
+ */
+struct xen_domctl_cacheflush {
+    /* IN: page range to flush, inclusive. */
+    xen_pfn_t start_pfn, end_pfn;
+};
+typedef struct xen_domctl_cacheflush xen_domctl_cacheflush_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_cacheflush_t);
+
 struct xen_domctl {
     uint32_t cmd;
 #define XEN_DOMCTL_createdomain                   1
@@ -954,6 +965,7 @@  struct xen_domctl {
 #define XEN_DOMCTL_setnodeaffinity               68
 #define XEN_DOMCTL_getnodeaffinity               69
 #define XEN_DOMCTL_set_max_evtchn                70
+#define XEN_DOMCTL_cacheflush                    71
 #define XEN_DOMCTL_gdbsx_guestmemio            1000
 #define XEN_DOMCTL_gdbsx_pausevcpu             1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -1012,6 +1024,7 @@  struct xen_domctl {
         struct xen_domctl_set_max_evtchn    set_max_evtchn;
         struct xen_domctl_gdbsx_memio       gdbsx_guest_memio;
         struct xen_domctl_set_broken_page_p2m set_broken_page_p2m;
+        struct xen_domctl_cacheflush        cacheflush;
         struct xen_domctl_gdbsx_pauseunp_vcpu gdbsx_pauseunp_vcpu;
         struct xen_domctl_gdbsx_domstatus   gdbsx_domstatus;
         uint8_t                             pad[128];
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 50a35fc..1345d7e 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -737,6 +737,9 @@  static int flask_domctl(struct domain *d, int cmd)
     case XEN_DOMCTL_set_max_evtchn:
         return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__SET_MAX_EVTCHN);
 
+    case XEN_DOMCTL_cacheflush:
+	    return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__CACHEFLUSH);
+
     default:
         printk("flask_domctl: Unknown op %d\n", cmd);
         return -EPERM;
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index 1fbe241..a0ed13d 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -196,6 +196,8 @@  class domain2
     setclaim
 # XEN_DOMCTL_set_max_evtchn
     set_max_evtchn
+# XEN_DOMCTL_cacheflush
+    cacheflush
 }
 
 # Similar to class domain, but primarily contains domctls related to HVM domains