[Xen-changelog] [xen-unstable] x86: add support for domain-initiated global cache flush

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1272973271 -3600
# Node ID 6c7b905b03ff1cf171187bafe7129e3e213e5787
# Parent  bd52f2e040e5a5ca58e956b3d0780a86934a429e
x86: add support for domain-initiated global cache flush

Newer Linux' AGP code wants to flush caches on all CPUs under certain
circumstances. Since doing this on all vCPU-s of the domain in
question doesn't yield the intended effect, this needs to be done in
the hypervisor. Add a new MMUEXT operation for this.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 xen/arch/x86/mm.c        |   21 +++++++++++++++++++++
 xen/include/public/xen.h |    5 +++++
 2 files changed, 26 insertions(+)

diff -r bd52f2e040e5 -r 6c7b905b03ff xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Tue May 04 12:39:29 2010 +0100
+++ b/xen/arch/x86/mm.c Tue May 04 12:41:11 2010 +0100
@@ -2888,6 +2888,27 @@ int do_mmuext_op(
             }
             break;
 
+        case MMUEXT_FLUSH_CACHE_GLOBAL:
+            if ( unlikely(foreigndom != DOMID_SELF) )
+                okay = 0;
+            else if ( likely(cache_flush_permitted(d)) )
+            {
+                unsigned int cpu;
+                cpumask_t mask = CPU_MASK_NONE;
+
+                for_each_online_cpu(cpu)
+                    if ( !cpus_intersects(mask,
+                                          per_cpu(cpu_sibling_map, cpu)) )
+                        cpu_set(cpu, mask);
+                flush_mask(&mask, FLUSH_CACHE);
+            }
+            else
+            {
+                MEM_LOG("Non-physdev domain tried to FLUSH_CACHE_GLOBAL");
+                okay = 0;
+            }
+            break;
+
         case MMUEXT_SET_LDT:
         {
             unsigned long ptr  = op.arg1.linear_addr;
diff -r bd52f2e040e5 -r 6c7b905b03ff xen/include/public/xen.h
--- a/xen/include/public/xen.h  Tue May 04 12:39:29 2010 +0100
+++ b/xen/include/public/xen.h  Tue May 04 12:41:11 2010 +0100
@@ -239,6 +239,10 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
  * 
  * cmd: MMUEXT_FLUSH_CACHE
  * No additional arguments. Writes back and flushes cache contents.
+ *
+ * cmd: MMUEXT_FLUSH_CACHE_GLOBAL
+ * No additional arguments. Writes back and flushes cache contents
+ * on all CPUs in the system.
  * 
  * cmd: MMUEXT_SET_LDT
  * linear_addr: Linear address of LDT base (NB. must be page-aligned).
@@ -268,6 +272,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
 #define MMUEXT_NEW_USER_BASEPTR 15
 #define MMUEXT_CLEAR_PAGE       16
 #define MMUEXT_COPY_PAGE        17
+#define MMUEXT_FLUSH_CACHE_GLOBAL 18
 
 #ifndef __ASSEMBLY__
 struct mmuext_op {

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