[Xen-changelog] [xen-unstable] [IA64] Fix frametable_miss handling for HVM guests.

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

# HG changeset patch
# User Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
# Date 1226054099 -32400
# Node ID 9bc00e9716cd8c7d3fe0ffd71b28d3235fc125ac
# Parent  b9436a3c9f0034c2f8299102a8ead3437e457ef4
[IA64] Fix frametable_miss handling for HVM guests.

For hvm guests, hypervisor use mfn_valid to check mfn, but it will incur
weird faults. It is becasue ipsr is saved in r29, but frametalbe miss assumes
saved in r21.

Signed-off-by: Xiantao Zhang <xiantao.zhang@xxxxxxxxx>
---
 xen/arch/ia64/vmx/vmx_ivt.S |    4 ++--
 xen/arch/ia64/xen/ivt.S     |   16 +++++++++-------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff -r b9436a3c9f00 -r 9bc00e9716cd xen/arch/ia64/vmx/vmx_ivt.S
--- a/xen/arch/ia64/vmx/vmx_ivt.S       Fri Nov 07 12:05:14 2008 +0900
+++ b/xen/arch/ia64/vmx/vmx_ivt.S       Fri Nov 07 19:34:59 2008 +0900
@@ -343,7 +343,7 @@ END(vmx_alt_itlb_miss)
 // 0x1000 Entry 4 (size 64 bundles) Alt DTLB (7,46)
 ENTRY(vmx_alt_dtlb_miss)
     VMX_DBG_FAULT(4)
-    mov r29=cr.ipsr
+    mov r29=cr.ipsr    //frametable_miss needs ipsr is saved in r29.
     mov r31=pr
     adds r22=IA64_VCPU_MMU_MODE_OFFSET, r21
     ;;
@@ -356,7 +356,7 @@ vmx_alt_dtlb_miss_vmm:
     // Test for the address of virtual frame_table
     shr r22=r16,56;;
     cmp.eq p8,p0=((VIRT_FRAME_TABLE_ADDR>>56)&0xff)-0x100,r22
-(p8)br.cond.sptk frametable_miss ;;
+(p8)br.cond.sptk frametable_miss ;; //Make sure ipsr is saved in r29
 #endif
     movl r17=PAGE_KERNEL
     mov r20=cr.isr
diff -r b9436a3c9f00 -r 9bc00e9716cd xen/arch/ia64/xen/ivt.S
--- a/xen/arch/ia64/xen/ivt.S   Fri Nov 07 12:05:14 2008 +0900
+++ b/xen/arch/ia64/xen/ivt.S   Fri Nov 07 19:34:59 2008 +0900
@@ -184,10 +184,12 @@ late_alt_dtlb_miss:
 late_alt_dtlb_miss:
        mov r20=cr.isr
        movl r17=PAGE_KERNEL
-       mov r21=cr.ipsr
+       mov r29=cr.ipsr // frametable_miss is shared by paravirtual and HVM 
sides
+                       // and it assumes ipsr is saved in r29. If change the
+                       // registers usage here, please check both sides!   
        movl r19=(((1 << IA64_MAX_PHYS_BITS) - 1) & ~0xfff)
        ;;
-       extr.u r23=r21,IA64_PSR_CPL0_BIT,2      // extract psr.cpl
+       extr.u r23=r29,IA64_PSR_CPL0_BIT,2      // extract psr.cpl
        and r22=IA64_ISR_CODE_MASK,r20          // get the isr.code field
        tbit.nz p6,p7=r20,IA64_ISR_SP_BIT       // is speculation bit on?
        extr.u r18=r16,XEN_VIRT_UC_BIT,1        // extract UC bit
@@ -234,7 +236,7 @@ late_alt_dtlb_miss:
        br.cond.spnt page_fault
        ;;
 alt_dtlb_miss_identity_map:
-       dep r21=-1,r21,IA64_PSR_ED_BIT,1
+       dep r29=-1,r29,IA64_PSR_ED_BIT,1
        or r19=r19,r17          // insert PTE control bits into r19
        mov cr.itir=r20         // set itir with cleared key
        ;;
@@ -243,7 +245,7 @@ alt_dtlb_miss_identity_map:
        cmp.eq.or p8,p0=0x18,r22        // Region 6 is UC for EFI
        ;;
 (p8)   dep r19=-1,r19,4,1      // set bit 4 (uncached) if access to UC area
-(p6)   mov cr.ipsr=r21
+(p6)   mov cr.ipsr=r29
        ;;
 (p7)   itc.d r19               // insert the TLB entry
        mov pr=r31,-1
@@ -288,17 +290,17 @@ GLOBAL_ENTRY(frametable_miss)
        rfi
 END(frametable_miss)
 
-ENTRY(frametable_fault)
+ENTRY(frametable_fault)                //ipsr saved in r29 before coming here!
        ssm psr.dt              // switch to using virtual data addressing
        mov r18=cr.iip
        movl r19=ia64_frametable_probe
        ;;
        cmp.eq p6,p7=r18,r19    // is faulting addrress ia64_frametable_probe?
        mov r8=0                // assumes that 'probe.r' uses r8
-       dep r21=-1,r21,IA64_PSR_RI_BIT+1,1 // return to next instruction in
+       dep r29=-1,r29,IA64_PSR_RI_BIT+1,1 // return to next instruction in
                                           //   bundle 2
        ;;
-(p6)   mov cr.ipsr=r21
+(p6)   mov cr.ipsr=r29
        mov r19=4               // FAULT(4)
 (p7)   br.spnt.few dispatch_to_fault_handler
        ;;

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