[Xen-devel] RFC: Nested VMX patch series 10: vmcs switching API

["Dong, Eddie" <eddie.dong@xxxxxxxxx>]

Thx, Eddie

        Signed-off-by: Qing He <qing.he@xxxxxxxxx>
        Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>

diff -r e6ae904dc440 xen/arch/x86/hvm/vmx/vmcs.c
--- a/xen/arch/x86/hvm/vmx/vmcs.c       Tue May 31 18:01:17 2011 +0800
+++ b/xen/arch/x86/hvm/vmx/vmcs.c       Wed Jun 01 08:34:24 2011 +0800
@@ -669,6 +669,38 @@
     }
 }
 
+/*
+ * Switch VMCS between layer 1 & 2 guest
+ */
+void vmx_vmcs_switch(struct vcpu *v,
+                             struct vmcs_struct *from,
+                             struct vmcs_struct *to)
+{
+    /* no foreign access */
+    if ( unlikely(v != current) )
+        return;
+
+    if ( unlikely(current->arch.hvm_vmx.vmcs != from) )
+        return;
+
+    spin_lock(&v->arch.hvm_vmx.vmcs_lock);
+
+    __vmpclear(virt_to_maddr(from));
+    __vmptrld(virt_to_maddr(to));
+
+    v->arch.hvm_vmx.vmcs = to;
+    v->arch.hvm_vmx.launched = 0;
+    this_cpu(current_vmcs) = to;
+
+    if ( v->arch.hvm_vmx.hostenv_migrated )
+    {
+        v->arch.hvm_vmx.hostenv_migrated = 0;
+        vmx_set_host_env(v);
+    }
+
+    spin_unlock(&v->arch.hvm_vmx.vmcs_lock);
+}
+
 static int construct_vmcs(struct vcpu *v)
 {
     struct domain *d = v->domain;
@@ -1078,6 +1110,13 @@
         hvm_migrate_timers(v);
         hvm_migrate_pirqs(v);
         vmx_set_host_env(v);
+        /*
+         * Both n1 VMCS and n2 VMCS need to update the host environment after 
+         * VCPU migration. The environment of current VMCS is updated in place,
+         * but the action of another VMCS is deferred till it is switched in.
+         */
+        v->arch.hvm_vmx.hostenv_migrated = 1;
+
         hvm_asid_flush_vcpu(v);
     }
 
diff -r e6ae904dc440 xen/include/asm-x86/hvm/vmx/vmcs.h
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h        Tue May 31 18:01:17 2011 +0800
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h        Wed Jun 01 08:34:24 2011 +0800
@@ -123,6 +123,7 @@
     struct segment_register vm86_saved_seg[x86_seg_tr + 1];
     /* Remember EFLAGS while in virtual 8086 mode */
     uint32_t             vm86_saved_eflags;
+    int                  hostenv_migrated;
 };
 
 int vmx_create_vmcs(struct vcpu *v);
@@ -390,6 +391,9 @@
 int vmx_write_guest_msr(u32 msr, u64 val);
 int vmx_add_guest_msr(u32 msr);
 int vmx_add_host_load_msr(u32 msr);
+void vmx_vmcs_switch(struct vcpu *v,
+                      struct vmcs_struct *from,
+                      struct vmcs_struct *to);
 
 #endif /* ASM_X86_HVM_VMX_VMCS_H__ */


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