[Xen-devel] [PATCH] Don't expose CPUID time leaf when not using PVRDTSCP

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

# HG changeset patch
# User Paul Durrant <paul.durrant@xxxxxxxxxx>
# Date 1309796247 -3600
# Node ID 6ce0dbc6f955707bf814d62a16a2b4382d957332
# Parent  7e4404a8f5f9bc111a80f15a2bce35378b39f2f1
Don't expose CPUID time leaf when not using PVRDTSCP

Some versions of Oracle's Solaris PV drivers make a check that the maximal
Xen hypervisor CPUID leaf is <= base leaf + 2 and refuse to work if this
is not the case.
The addition of the time leaf makes the maximal leaf == base leaf + 3 so
this patch introduces a workaround that obscures the time leaf unless
PVRDTSCP is in operation.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

diff -r 7e4404a8f5f9 -r 6ce0dbc6f955 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c      Mon Jul 04 07:57:32 2011 +0100
+++ b/xen/arch/x86/traps.c      Mon Jul 04 17:17:27 2011 +0100
@@ -704,15 +704,19 @@ int cpuid_hypervisor_leaves( uint32_t id
     struct domain *d = current->domain;
     /* Optionally shift out of the way of Viridian architectural leaves. */
     uint32_t base = is_viridian_domain(d) ? 0x40000100 : 0x40000000;
+    uint32_t limit;
 
     idx -= base;
-    if ( idx > 3 ) 
+
+    limit = (d->arch.tsc_mode < TSC_MODE_PVRDTSCP) ? 2 : 3;
+
+    if ( idx > limit ) 
         return 0;
 
     switch ( idx )
     {
     case 0:
-        *eax = base + 3; /* Largest leaf */
+        *eax = base + limit; /* Largest leaf */
         *ebx = XEN_CPUID_SIGNATURE_EBX;
         *ecx = XEN_CPUID_SIGNATURE_ECX;
         *edx = XEN_CPUID_SIGNATURE_EDX;

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