KVM: VMX: Handle #SS faults from real mode

Instructions with address size override prefix opcode 0x67
Cause the #SS fault with 0 error code in VM86 mode.  Forward
them to the emulator.

Signed-Off-By: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index c4c5535..a05bfa0 100644 (file)
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1488,7 +1488,11 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
        if (!vcpu->rmode.active)
                return 0;
 
-       if (vec == GP_VECTOR && err_code == 0)
+       /*
+        * Instruction with address size override prefix opcode 0x67
+        * Cause the #SS fault with 0 error code in VM86 mode.
+        */
+       if (((vec == GP_VECTOR) || (vec == SS_VECTOR)) && err_code == 0)
                if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE)
                        return 1;
        return 0;