[Xen-changelog] [xen master] VMX: Eliminate cr3 save/loading exiting when UG enabled

[patchbot@xxxxxxx]

commit f4fed540e78ac8a2bd3b1dee53a5206dde25f613
Author:     Yang Zhang <yang.z.zhang@xxxxxxxxx>
AuthorDate: Tue Jan 7 14:30:47 2014 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jan 7 14:30:47 2014 +0100

    VMX: Eliminate cr3 save/loading exiting when UG enabled
    
    With the feature of unrestricted guest, there should be no vmexit
    be triggered when guest accesses the cr3 in non-paging mode. This
    patch will clear the cr3 save/loading bit in vmcs control filed to
    eliminate cr3 access vmexit on UG avaliable hardware.
    
    The previous patch (commit c9efe34c119418a5ac776e5d91aeefcce4576518)
    did the same thing compare to this one. But it will cause guest fail
    to boot up on non-UG hardware which is repoted by Jan and it has been
    reverted (commit 1e2bf05ec37cf04b0e01585eae524509179f165e).
    
    This patch incorporate the fixing and guest are working well both in
    UG and non-UG platform with this patch.
    
    Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
    Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index dfff628..f6409d6 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1157,7 +1157,7 @@ static void vmx_update_guest_cr(struct vcpu *v, unsigned 
int cr)
             uint32_t cr3_ctls = (CPU_BASED_CR3_LOAD_EXITING |
                                  CPU_BASED_CR3_STORE_EXITING);
             v->arch.hvm_vmx.exec_control &= ~cr3_ctls;
-            if ( !hvm_paging_enabled(v) )
+            if ( !hvm_paging_enabled(v) && !vmx_unrestricted_guest(v) )
                 v->arch.hvm_vmx.exec_control |= cr3_ctls;
 
             /* Trap CR3 updates if CR3 memory events are enabled. */
@@ -1231,7 +1231,7 @@ static void vmx_update_guest_cr(struct vcpu *v, unsigned 
int cr)
     case 3:
         if ( paging_mode_hap(v->domain) )
         {
-            if ( !hvm_paging_enabled(v) )
+            if ( !hvm_paging_enabled(v) && !vmx_unrestricted_guest(v) )
                 v->arch.hvm_vcpu.hw_cr[3] =
                     v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT];
             vmx_load_pdptrs(v);
@@ -2487,10 +2487,11 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
 
     hvm_invalidate_regs_fields(regs);
 
-    if ( paging_mode_hap(v->domain) && hvm_paging_enabled(v) )
+    if ( paging_mode_hap(v->domain) )
     {
         __vmread(GUEST_CR3, &v->arch.hvm_vcpu.hw_cr[3]);
-        v->arch.hvm_vcpu.guest_cr[3] = v->arch.hvm_vcpu.hw_cr[3];
+        if ( vmx_unrestricted_guest(v) || hvm_paging_enabled(v) )
+            v->arch.hvm_vcpu.guest_cr[3] = v->arch.hvm_vcpu.hw_cr[3];
     }
 
     __vmread(VM_EXIT_REASON, &exit_reason);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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