Re: [Xen-devel] [RFC Patch 24/25] fix vm entry fail

[Tim Deegan <tim@xxxxxxx>]

Hi,

At 19:39 +0800 on 18 Jul (1405708749), Wen Congyang wrote:
> In colo mode, secondary vm is running, so VM_ENTRY_INTR_INFO may
> valid before restoring vmcs. If there is no pending event after
> restoring vm, we should clear it.

> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>

This looks correct but incomplete -- we should also clear this state for
the other cases where we don't explicitly set it.  I've done this
below, and also copied the fix to the equivalent SVM code.  Can you
test that it works for you?

Cheers,

Tim.

commit c9e81a06c02ffc45594798616409335fc09cd32f
Author: Wen Congyang <wency@xxxxxxxxxxxxxx>
Date:   Fri Jul 18 19:39:09 2014 +0800

    x86/hvm: Always set pending event injection when loading VMC[BS] state.
    
    In colo mode, secondary vm is running, so VM_ENTRY_INTR_INFO may
    valid before restoring vmcs. If there is no pending event after
    restoring vm, we should clear it.
    
    Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
    
    Also clear pending software exceptions.
    Copy the fix to SVM as well.
    
    Signed-off-by: Tim Deegan <tim@xxxxxxx>

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 76616ac..6551b38 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -321,16 +321,18 @@ static int svm_vmcb_restore(struct vcpu *v, struct 
hvm_hw_cpu *c)
         vmcb_set_h_cr3(vmcb, pagetable_get_paddr(p2m_get_pagetable(p2m)));
     }
 
-    if ( c->pending_valid ) 
+    if ( c->pending_valid
+         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
     {
         gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
                  c->pending_event, c->error_code);
-
-        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
-        {
-            vmcb->eventinj.bytes = c->pending_event;
-            vmcb->eventinj.fields.errorcode = c->error_code;
-        }
+        vmcb->eventinj.bytes = c->pending_event;
+        vmcb->eventinj.fields.errorcode = c->error_code;
+    }
+    else
+    {
+        vmcb->eventinj.bytes = 0;
+        vmcb->eventinj.fields.errorcode = 0;
     }
 
     vmcb->cleanbits.bytes = 0;
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 2caa04a..cfc4801 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -509,23 +509,22 @@ static int vmx_vmcs_restore(struct vcpu *v, struct 
hvm_hw_cpu *c)
 
     __vmwrite(GUEST_DR7, c->dr7);
 
-    vmx_vmcs_exit(v);
-
-    paging_update_paging_modes(v);
-
-    if ( c->pending_valid )
+    if ( c->pending_valid
+         && hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
     {
         gdprintk(XENLOG_INFO, "Re-injecting %#"PRIx32", %#"PRIx32"\n",
                  c->pending_event, c->error_code);
-
-        if ( hvm_event_needs_reinjection(c->pending_type, c->pending_vector) )
-        {
-            vmx_vmcs_enter(v);
-            __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
-            __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
-            vmx_vmcs_exit(v);
-        }
+        __vmwrite(VM_ENTRY_INTR_INFO, c->pending_event);
+        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, c->error_code);
     }
+    else
+    {
+        __vmwrite(VM_ENTRY_INTR_INFO, 0);
+        __vmwrite(VM_ENTRY_EXCEPTION_ERROR_CODE, 0);
+    }
+    vmx_vmcs_exit(v);
+
+    paging_update_paging_modes(v);
 
     return 0;
 }

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