[Xen-devel] [PATCH 2/2 V3] x86/AMD: Inject #GP instead of #UD when unable to map vmcb

[<suravee.suthikulpanit@xxxxxxx>]

From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

According to AMD Programmer's Manual vol2, vmrun, vmsave and vmload
should inject #GP instead of #UD when unable to access memory
location for vmcb.  Also, the code should make sure that L1 guest
EFER.SVME is not zero.  Otherwise, #UD should be injected.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Reviewed-by: Tim Deegan <tim@xxxxxxx>
---
Changes from V2:
        - rename hvm_svm_enabled macro to nsvm_efer_svm_enabled (as Jan 
commented)
        - replace the nestedhvm_enabled() with nsvm_efer_svm_enabled()

 xen/arch/x86/hvm/svm/svm.c              |   24 ++++++++++++++----------
 xen/include/asm-x86/hvm/svm/nestedsvm.h |    2 +-
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index a20540b..f74265a 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1779,15 +1779,17 @@ static void
 svm_vmexit_do_vmrun(struct cpu_user_regs *regs,
                     struct vcpu *v, uint64_t vmcbaddr)
 {
-    if (!nestedhvm_enabled(v->domain)) {
+    if ( !nsvm_efer_svm_enabled(v) )
+    {
         gdprintk(XENLOG_ERR, "VMRUN: nestedhvm disabled, injecting #UD\n");
         hvm_inject_hw_exception(TRAP_invalid_op, HVM_DELIVER_NO_ERROR_CODE);
         return;
     }
 
-    if (!nestedsvm_vmcb_map(v, vmcbaddr)) {
-        gdprintk(XENLOG_ERR, "VMRUN: mapping vmcb failed, injecting #UD\n");
-        hvm_inject_hw_exception(TRAP_invalid_op, HVM_DELIVER_NO_ERROR_CODE);
+    if ( !nestedsvm_vmcb_map(v, vmcbaddr) )
+    {
+        gdprintk(XENLOG_ERR, "VMRUN: mapping vmcb failed, injecting #GP\n");
+        hvm_inject_hw_exception(TRAP_gp_fault, HVM_DELIVER_NO_ERROR_CODE);
         return;
     }
 
@@ -1833,7 +1835,8 @@ svm_vmexit_do_vmload(struct vmcb_struct *vmcb,
     if ( (inst_len = __get_instruction_length(v, INSTR_VMLOAD)) == 0 )
         return;
 
-    if (!nestedhvm_enabled(v->domain)) {
+    if ( !nsvm_efer_svm_enabled(v) ) 
+    {
         gdprintk(XENLOG_ERR, "VMLOAD: nestedhvm disabled, injecting #UD\n");
         ret = TRAP_invalid_op;
         goto inject;
@@ -1843,8 +1846,8 @@ svm_vmexit_do_vmload(struct vmcb_struct *vmcb,
     if ( !page )
     {
         gdprintk(XENLOG_ERR,
-            "VMLOAD: mapping failed, injecting #UD\n");
-        ret = TRAP_invalid_op;
+            "VMLOAD: mapping failed, injecting #GP\n");
+        ret = TRAP_gp_fault;
         goto inject;
     }
 
@@ -1874,7 +1877,8 @@ svm_vmexit_do_vmsave(struct vmcb_struct *vmcb,
     if ( (inst_len = __get_instruction_length(v, INSTR_VMSAVE)) == 0 )
         return;
 
-    if (!nestedhvm_enabled(v->domain)) {
+    if ( !nsvm_efer_svm_enabled(v) ) 
+    {
         gdprintk(XENLOG_ERR, "VMSAVE: nestedhvm disabled, injecting #UD\n");
         ret = TRAP_invalid_op;
         goto inject;
@@ -1884,8 +1888,8 @@ svm_vmexit_do_vmsave(struct vmcb_struct *vmcb,
     if ( !page )
     {
         gdprintk(XENLOG_ERR,
-            "VMSAVE: mapping vmcb failed, injecting #UD\n");
-        ret = TRAP_invalid_op;
+            "VMSAVE: mapping vmcb failed, injecting #GP\n");
+        ret = TRAP_gp_fault;
         goto inject;
     }
 
diff --git a/xen/include/asm-x86/hvm/svm/nestedsvm.h 
b/xen/include/asm-x86/hvm/svm/nestedsvm.h
index 0bc663a..f88b1bd 100644
--- a/xen/include/asm-x86/hvm/svm/nestedsvm.h
+++ b/xen/include/asm-x86/hvm/svm/nestedsvm.h
@@ -94,7 +94,7 @@ struct nestedsvm {
 #define vcpu_nestedsvm(v) (vcpu_nestedhvm(v).u.nsvm)
 
 /* True when l1 guest enabled SVM in EFER */
-#define hvm_svm_enabled(v) \
+#define nsvm_efer_svm_enabled(v) \
     (!!((v)->arch.hvm_vcpu.guest_efer & EFER_SVME))
 
 int nestedsvm_vmcb_map(struct vcpu *v, uint64_t vmcbaddr);
-- 
1.7.10.4



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