[Xen-changelog] [xen-4.1-testing] Fix PV CPUID virtualization of XSave

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Shan Haitao <haitao.shan@xxxxxxxxx>
# Date 1331106910 0
# Node ID 7ee4016eeb9fb1c05f033e2b9da78cf5564c3e54
# Parent  04d72f81775d66d159f4f2aea7723bb1ad432564
Fix PV CPUID virtualization of XSave

The patch will fix XSave CPUID virtualization for PV guests. The XSave
area size returned by CPUID leaf D is changed dynamically depending on
the XCR0. Tools/libxc only assigns a static value. The fix will adjust
xsave area size during runtime.

Note: This fix is already in HVM cpuid virtualization. And Dom0 is not
affected, either.

Signed-off-by:  Shan Haitao <haitao.shan@xxxxxxxxx>
xen-unstable changeset:   23853:b78235de5c64
xen-unstable date:        Sun Sep 18 00:01:58 2011 +0100

x86: Further fixes for xsave leaf in pv_cpuid().

Signed-off-by: Shan Haitao <haitao.shan@xxxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
xen-unstable changeset:   23955:bbde1453cbd9
xen-unstable date:        Thu Oct 13 15:58:55 2011 +0100
---


diff -r 04d72f81775d -r 7ee4016eeb9f xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Thu Feb 23 10:37:13 2012 +0000
+++ b/xen/arch/x86/hvm/hvm.c    Wed Mar 07 07:55:10 2012 +0000
@@ -2230,7 +2230,7 @@
         {
             /* reset EBX to default value first */
             *ebx = XSAVE_AREA_MIN_SIZE; 
-            for ( sub_leaf = 2; sub_leaf < 64; sub_leaf++ )
+            for ( sub_leaf = 2; sub_leaf < 63; sub_leaf++ )
             {
                 if ( !(v->arch.xcr0 & (1ULL << sub_leaf)) )
                     continue;
diff -r 04d72f81775d -r 7ee4016eeb9f xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c      Thu Feb 23 10:37:13 2012 +0000
+++ b/xen/arch/x86/traps.c      Wed Mar 07 07:55:10 2012 +0000
@@ -734,8 +734,34 @@
 
     if ( current->domain->domain_id != 0 )
     {
+        unsigned int cpuid_leaf = a, sub_leaf = c;
+
         if ( !cpuid_hypervisor_leaves(a, c, &a, &b, &c, &d) )
             domain_cpuid(current->domain, a, c, &a, &b, &c, &d);
+
+        switch ( cpuid_leaf )
+        {
+        case 0xd:
+        {
+            unsigned int _eax, _ebx, _ecx, _edx;
+            /* EBX value of main leaf 0 depends on enabled xsave features */
+            if ( sub_leaf == 0 && current->arch.xcr0 )
+            {
+                /* reset EBX to default value first */
+                b = XSAVE_AREA_MIN_SIZE;
+                for ( sub_leaf = 2; sub_leaf < 63; sub_leaf++ )
+                {
+                    if ( !(current->arch.xcr0 & (1ULL << sub_leaf)) )
+                        continue;
+                    domain_cpuid(current->domain, cpuid_leaf, sub_leaf,
+                                 &_eax, &_ebx, &_ecx, &_edx);
+                    if ( (_eax + _ebx) > b )
+                        b = _eax + _ebx;
+                }
+            }
+        break;
+        }
+        }
         goto out;
     }
 

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