[Xen-ia64-devel] [patch 04/14] ia64: kexec: Unpin the correct VHPT TR in ia64_do_tlb_purge

[Simon Horman <horms@xxxxxxxxxxxx>]

GET_VA_VCPU_VHPT_MADDR(r2,r3) does not give the value of the VHPT
pinned into the TLB. I believe that this is because
current is changed between pinning and calling play_dead,
though I am not sure of the exact scemantics.

In any case, by recording the pinned value in a percpu variable,
and unpinning this value, the TR entry is removed and all is well.

Cc: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>

--- 

Mon, 21 Apr 2008 11:50:41 +1000
* Also save the vhpt when it is set in vmx_load_all_rr()
  and vmx_vcpu_set_rr()

Wed, 07 May 2008 17:51:57 +1000
* Move definition of inserted_vhpt up to top regionreg.c

Thu, 10 Jul 2008 10:16:37 +1000
* vmx_load_all_rr() and vmx_vcpu_set_rr() set the VHPT to
  vcpu->arch.vhpt.hash not __va_ul(vcpu_vhpt_maddr(v)).
  So save the former in __get_cpu_var(inserted_vhpt) rather
  than the latter.

  This is done regarless of if VHPT_ENABLED is set or not,
  so the unpinning in ia64_do_tlb_purge should be done
  unconditionally.


Index: xen-unstable.hg/xen/arch/ia64/linux-xen/mca_asm.S
===================================================================
--- xen-unstable.hg.orig/xen/arch/ia64/linux-xen/mca_asm.S      2008-07-14 
16:20:58.000000000 +1000
+++ xen-unstable.hg/xen/arch/ia64/linux-xen/mca_asm.S   2008-07-14 
16:21:12.000000000 +1000
@@ -321,8 +321,13 @@ ia64_do_tlb_purge:
        ;;
 #ifdef XEN
        // 5. VHPT
-#if VHPT_ENABLED
-       GET_VA_VCPU_VHPT_MADDR(r2,r3);;
+       // GET_VA_VCPU_VHPT_MADDR() may not give the
+       // value of the VHPT currently pinned into the TLB
+       GET_THIS_PADDR(r2, inserted_vhpt);;
+       ;;
+       cmp.eq p7,p0=r2,r0
+       ;;
+(p7)   br.cond.sptk .vhpt_not_mapped
        dep r16=0,r2,0,IA64_GRANULE_SHIFT
        mov r18=IA64_GRANULE_SHIFT<<2
        ;;
@@ -330,7 +335,7 @@ ia64_do_tlb_purge:
        ;;
        srlz.d
        ;;
-#endif
+.vhpt_not_mapped:
 #endif
        // Now branch away to caller.
        br.sptk.many b1
Index: xen-unstable.hg/xen/arch/ia64/xen/regionreg.c
===================================================================
--- xen-unstable.hg.orig/xen/arch/ia64/xen/regionreg.c  2008-07-14 
16:20:58.000000000 +1000
+++ xen-unstable.hg/xen/arch/ia64/xen/regionreg.c       2008-07-14 
16:21:12.000000000 +1000
@@ -15,6 +15,7 @@
 #include <asm/regionreg.h>
 #include <asm/vhpt.h>
 #include <asm/vcpu.h>
+#include <asm/percpu.h>
 
 /* Defined in xemasm.S  */
 extern void ia64_new_rr7(unsigned long rid, void *shared_info, void 
*shared_arch_info, unsigned long shared_info_va, unsigned long va_vhpt);
@@ -47,6 +48,8 @@ extern void ia64_new_rr7(unsigned long r
 static unsigned int domain_rid_bits_default = IA64_MIN_IMPL_RID_BITS;
 integer_param("dom_rid_bits", domain_rid_bits_default); 
 
+DEFINE_PER_CPU(unsigned long, inserted_vhpt);
+
 #if 0
 // following already defined in include/asm-ia64/gcc_intrin.h
 // it should probably be ifdef'd out from there to ensure all region
@@ -260,6 +263,9 @@ int set_one_rr(unsigned long rr, unsigne
                if (!PSCB(v,metaphysical_mode))
                        set_rr(rr,newrrv.rrval);
        } else if (rreg == 7) {
+#if VHPT_ENABLED
+               __get_cpu_var(inserted_vhpt) = __va_ul(vcpu_vhpt_maddr(v));
+#endif
                ia64_new_rr7(vmMangleRID(newrrv.rrval),v->domain->shared_info,
                             v->arch.privregs, v->domain->arch.shared_info_va,
                             __va_ul(vcpu_vhpt_maddr(v)));
Index: xen-unstable.hg/xen/arch/ia64/vmx/vmx_vcpu.c
===================================================================
--- xen-unstable.hg.orig/xen/arch/ia64/vmx/vmx_vcpu.c   2008-07-14 
16:21:10.000000000 +1000
+++ xen-unstable.hg/xen/arch/ia64/vmx/vmx_vcpu.c        2008-07-14 
16:22:43.000000000 +1000
@@ -199,6 +199,7 @@ void vmx_vcpu_set_rr_fast(VCPU *vcpu, u6
 void vmx_switch_rr7(unsigned long rid, void *guest_vhpt,
                     void *pal_vaddr, void *shared_arch_info)
 {
+    __get_cpu_var(inserted_vhpt) = guest_vhpt;
     __vmx_switch_rr7(rid, guest_vhpt, pal_vaddr, shared_arch_info);
 }
 
Index: xen-unstable.hg/xen/include/asm-ia64/regionreg.h
===================================================================
--- xen-unstable.hg.orig/xen/include/asm-ia64/regionreg.h       2008-07-14 
16:20:58.000000000 +1000
+++ xen-unstable.hg/xen/include/asm-ia64/regionreg.h    2008-07-14 
16:21:12.000000000 +1000
@@ -36,6 +36,7 @@ typedef union ia64_rr {
 #define RR_RID(arg)     (((arg) & 0x0000000000ffffff) << 8)
 #define RR_RID_MASK     0x00000000ffffff00L
 
+DECLARE_PER_CPU(unsigned long, inserted_vhpt);
 
 int set_one_rr(unsigned long rr, unsigned long val);
 

-- 

-- 
Horms


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