File 19474-32on64-S3.patch of Package xen

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1238502525 -3600
# Node ID 0faf7b884711a958d9073edb64d191d9a07fc064
# Parent  d7bf5a03cf074cc6213b1c79478c4b14041e0867
x86: Enable S3 for 32bit dom0 on 64bit Xen

Three SYSENTER MSRs should be taken care of at save/restore BSP
context, or else 32bit dom0 rejects working after S3 resume. Thanks
for Jan's help to find this missing part.

Signed-off-by: Guanqun Lu <guanqun.lu@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>

--- a/xen/arch/x86/acpi/suspend.c
+++ b/xen/arch/x86/acpi/suspend.c
@@ -16,6 +16,7 @@
 
 #if defined(CONFIG_X86_64)
 static unsigned long saved_lstar, saved_cstar;
+static unsigned long saved_sysenter_esp, saved_sysenter_eip;
 #endif
 
 void save_rest_processor_state(void)
@@ -26,6 +27,11 @@ void save_rest_processor_state(void)
 #if defined(CONFIG_X86_64)
     rdmsrl(MSR_CSTAR, saved_cstar);
     rdmsrl(MSR_LSTAR, saved_lstar);
+    if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
+    {
+        rdmsrl(MSR_IA32_SYSENTER_ESP, saved_sysenter_esp);
+        rdmsrl(MSR_IA32_SYSENTER_EIP, saved_sysenter_eip);
+    }
 #endif
 }
 
@@ -41,6 +47,14 @@ void restore_rest_processor_state(void)
     wrmsrl(MSR_CSTAR, saved_cstar);
     wrmsr(MSR_STAR, 0, (FLAT_RING3_CS32<<16) | __HYPERVISOR_CS);
     wrmsr(MSR_SYSCALL_MASK, EF_VM|EF_RF|EF_NT|EF_DF|EF_IE|EF_TF, 0U);    
+
+    if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
+    {
+        /* Recover sysenter MSRs */
+        wrmsrl(MSR_IA32_SYSENTER_ESP, saved_sysenter_esp);
+        wrmsrl(MSR_IA32_SYSENTER_EIP, saved_sysenter_eip);
+        wrmsr(MSR_IA32_SYSENTER_CS, __HYPERVISOR_CS, 0);
+    }
 #else /* !defined(CONFIG_X86_64) */
     if ( supervisor_mode_kernel && cpu_has_sep )
         wrmsr(MSR_IA32_SYSENTER_ESP, &init_tss[smp_processor_id()].esp1, 0);