bug fix for 32 bit ebp cloberring

[palacios.git] / palacios / src / palacios / svm_lowlevel.S

diff --git a/palacios/src/palacios/svm_lowlevel.S b/palacios/src/palacios/svm_lowlevel.S
index 0d5e870..45c5575 100644 (file)
--- a/palacios/src/palacios/svm_lowlevel.S
+++ b/palacios/src/palacios/svm_lowlevel.S
@@ -22,6 +22,8 @@
 
 #ifdef __V3_32BIT__
 
+// Note that RAX is saved in the VMCB, so we don't touch it here
+
 #define Save_SVM_Registers(location)   \
        pushl   %eax;                   \
        movl    location, %eax;         \
@@ -32,10 +34,6 @@
        movl    %ebx, 32(%eax);         \
        movl    %edx, 40(%eax);         \
        movl    %ecx, 48(%eax);         \
-       pushl   %ebx;                   \
-       movl    8(%esp), %ebx;          \
-       movl    %ebx, 56(%eax);         \
-       popl    %ebx;                   \
        popl    %eax;                   
        
 
@@ -76,12 +74,15 @@ v3_svm_launch:
 
        addl    $4, %esp;
 
+       popa;
+       popf;
 
        movl    16(%ebp), %eax;
        vmload;
 
-       popa;
-       popf;
+       // We don't detect failures here, so just return 0
+       xorl    %eax, %eax 
+
        pop     %ebp;
        ret
 
@@ -89,6 +90,8 @@ v3_svm_launch:
 
 #elif __V3_64BIT__
 
+// Note that RAX is saved in the VMCB, so we don't touch it here
+
 #define Save_SVM_Registers(location)   \
        pushq   %rax;                   \
        movq    location, %rax;         \
@@ -99,10 +102,6 @@ v3_svm_launch:
        movq    %rbx, 32(%rax);         \
        movq    %rdx, 40(%rax);         \
        movq    %rcx, 48(%rax);         \
-       pushq   %rbx;                   \
-       movq    16(%rsp), %rbx;         \
-       movq    %rbx, 56(%rax);         \
-       popq    %rbx;                   \
                                        \
        movq    %r8, 64(%rax);          \
        movq    %r9, 72(%rax);          \