From: Erik van der Kouwe <erikvdk@gmail.com>
Date: Fri, 26 Nov 2010 17:01:09 +0000 (-0600)
Subject: This patch virtualizes VM_CR_MSR to tell the guest it cannot use SVM.
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=5aac3f94fc38bfef003c41496089eb3793778342

This patch virtualizes VM_CR_MSR to tell the guest it cannot use SVM.
---

diff --git a/palacios/include/palacios/vmm_ctrl_regs.h b/palacios/include/palacios/vmm_ctrl_regs.h
index 0063473..e072a04 100644
--- a/palacios/include/palacios/vmm_ctrl_regs.h
+++ b/palacios/include/palacios/vmm_ctrl_regs.h
@@ -215,6 +215,9 @@ int v3_handle_cr4_read(struct guest_info * info);
 int v3_handle_efer_write(struct guest_info * core, uint_t msr, struct v3_msr src, void * priv_data);
 int v3_handle_efer_read(struct guest_info * core, uint_t msr, struct v3_msr * dst, void * priv_data);
 
+int v3_handle_vm_cr_write(struct guest_info * core, uint_t msr, struct v3_msr src, void * priv_data);
+int v3_handle_vm_cr_read(struct guest_info * core, uint_t msr, struct v3_msr * dst, void * priv_data);
+
 
 #endif // ! __V3VEE__
 
diff --git a/palacios/src/palacios/svm.c b/palacios/src/palacios/svm.c
index 975010f..f20d78c 100644
--- a/palacios/src/palacios/svm.c
+++ b/palacios/src/palacios/svm.c
@@ -279,6 +279,12 @@ static void Init_VMCB_BIOS(vmcb_t * vmcb, struct guest_info * core) {
 
 	guest_state->g_pat = 0x7040600070406ULL;
     }
+    
+    /* tell the guest that we don't support SVM */
+    v3_hook_msr(core->vm_info, SVM_VM_CR_MSR, 
+	&v3_handle_vm_cr_read,
+	&v3_handle_vm_cr_write, 
+	core);
 }
 
 
diff --git a/palacios/src/palacios/vmm_ctrl_regs.c b/palacios/src/palacios/vmm_ctrl_regs.c
index 1afb255..afecc74 100644
--- a/palacios/src/palacios/vmm_ctrl_regs.c
+++ b/palacios/src/palacios/vmm_ctrl_regs.c
@@ -24,6 +24,7 @@
 #include <palacios/vm_guest_mem.h>
 #include <palacios/vmm_ctrl_regs.h>
 #include <palacios/vmm_direct_paging.h>
+#include <palacios/svm.h>
 
 #ifndef CONFIG_DEBUG_CTRL_REGS
 #undef PrintDebug
@@ -571,3 +572,29 @@ int v3_handle_efer_write(struct guest_info * core, uint_t msr, struct v3_msr src
     
     return 0;
 }
+
+int v3_handle_vm_cr_read(struct guest_info * core, uint_t msr, struct v3_msr * dst, void * priv_data) {
+    /* tell the guest that the BIOS disabled SVM, that way it doesn't get 
+     * confused by the fact that CPUID reports SVM as available but it still
+     * cannot be used 
+     */
+    dst->value = SVM_VM_CR_MSR_lock | SVM_VM_CR_MSR_svmdis;
+    PrintDebug("VM_CR Read HI=%x LO=%x\n", dst->hi, dst->lo);
+    return 0;
+}
+
+int v3_handle_vm_cr_write(struct guest_info * core, uint_t msr, struct v3_msr src, void * priv_data) {
+    PrintDebug("VM_CR Write\n");
+    PrintDebug("VM_CR Write Values: HI=%x LO=%x\n", src.hi, src.lo);
+
+    /* writes to LOCK and SVMDIS are silently ignored (according to the spec), 
+     * other writes indicate the guest wants to use some feature we haven't
+     * implemented
+     */
+    if (src.value & ~(SVM_VM_CR_MSR_lock | SVM_VM_CR_MSR_svmdis)) {
+	PrintDebug("VM_CR write sets unsupported bits: HI=%x LO=%x\n", src.hi, src.lo);
+	return -1;
+    }
+    
+    return 0;
+}