$NetBSD: patch-xsa7-xsa8-xen-4.1,v 1.1.2.2 2012/06/20 17:54:12 tron Exp $

diff -r 35248be669e7 xen/arch/x86/x86_64/asm-offsets.c
--- xen/arch/x86/x86_64/asm-offsets.c.orig	Mon May 14 16:59:12 2012 +0100
+++ xen/arch/x86/x86_64/asm-offsets.c	Thu May 24 11:12:33 2012 +0100
@@ -90,6 +90,8 @@ void __dummy__(void)
            arch.guest_context.trap_ctxt[TRAP_gp_fault].address);
     OFFSET(VCPU_gp_fault_sel, struct vcpu,
            arch.guest_context.trap_ctxt[TRAP_gp_fault].cs);
+    OFFSET(VCPU_gp_fault_flags, struct vcpu,
+           arch.guest_context.trap_ctxt[TRAP_gp_fault].flags);
     OFFSET(VCPU_kernel_sp, struct vcpu, arch.guest_context.kernel_sp);
     OFFSET(VCPU_kernel_ss, struct vcpu, arch.guest_context.kernel_ss);
     OFFSET(VCPU_guest_context_flags, struct vcpu, arch.guest_context.flags);
diff -r 35248be669e7 xen/arch/x86/x86_64/compat/entry.S
--- xen/arch/x86/x86_64/compat/entry.S.orig	Mon May 14 16:59:12 2012 +0100
+++ xen/arch/x86/x86_64/compat/entry.S	Thu May 24 11:12:33 2012 +0100
@@ -214,6 +214,7 @@ 1:      call  compat_create_bounce_frame
 ENTRY(compat_post_handle_exception)
         testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx)
         jz    compat_test_all_events
+.Lcompat_bounce_exception:
         call  compat_create_bounce_frame
         movb  $0,TRAPBOUNCE_flags(%rdx)
         jmp   compat_test_all_events
@@ -226,19 +227,20 @@ ENTRY(compat_syscall)
         leaq  VCPU_trap_bounce(%rbx),%rdx
         testl $~3,%esi
         leal  (,%rcx,TBF_INTERRUPT),%ecx
-        jz    2f
-1:      movq  %rax,TRAPBOUNCE_eip(%rdx)
+UNLIKELY_START(z, compat_syscall_gpf)
+        movl  $TRAP_gp_fault,UREGS_entry_vector(%rsp)
+        subl  $2,UREGS_rip(%rsp)
+        movl  $0,TRAPBOUNCE_error_code(%rdx)
+        movl  VCPU_gp_fault_addr(%rbx),%eax
+        movzwl VCPU_gp_fault_sel(%rbx),%esi
+        testb $4,VCPU_gp_fault_flags(%rbx)
+        setnz %cl
+        leal  TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx
+UNLIKELY_END(compat_syscall_gpf)
+        movq  %rax,TRAPBOUNCE_eip(%rdx)
         movw  %si,TRAPBOUNCE_cs(%rdx)
         movb  %cl,TRAPBOUNCE_flags(%rdx)
-        call  compat_create_bounce_frame
-        jmp   compat_test_all_events
-2:      movl  $TRAP_gp_fault,UREGS_entry_vector(%rsp)
-        subl  $2,UREGS_rip(%rsp)
-        movq  VCPU_gp_fault_addr(%rbx),%rax
-        movzwl VCPU_gp_fault_sel(%rbx),%esi
-        movb  $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl
-        movl  $0,TRAPBOUNCE_error_code(%rdx)
-        jmp   1b
+        jmp   .Lcompat_bounce_exception
 
 ENTRY(compat_sysenter)
         cmpl  $TRAP_gp_fault,UREGS_entry_vector(%rsp)
diff -r 35248be669e7 xen/arch/x86/x86_64/entry.S
--- xen/arch/x86/x86_64/entry.S.orig	Mon May 14 16:59:12 2012 +0100
+++ xen/arch/x86/x86_64/entry.S	Thu May 24 11:12:33 2012 +0100
@@ -40,6 +40,13 @@ restore_all_guest:
         testw $TRAP_syscall,4(%rsp)
         jz    iret_exit_to_guest
 
+        /* Don't use SYSRET path if the return address is not canonical. */
+        movq  8(%rsp),%rcx
+        sarq  $47,%rcx
+        incl  %ecx
+        cmpl  $1,%ecx
+        ja    .Lforce_iret
+
         addq  $8,%rsp
         popq  %rcx                    # RIP
         popq  %r11                    # CS
@@ -50,6 +57,10 @@ restore_all_guest:
         sysretq
 1:      sysretl
 
+.Lforce_iret:
+        /* Mimic SYSRET behavior. */
+        movq  8(%rsp),%rcx            # RIP
+        movq  24(%rsp),%r11           # RFLAGS
         ALIGN
 /* No special register assumptions. */
 iret_exit_to_guest:
@@ -278,19 +289,21 @@ sysenter_eflags_saved:
         leaq  VCPU_trap_bounce(%rbx),%rdx
         testq %rax,%rax
         leal  (,%rcx,TBF_INTERRUPT),%ecx
-        jz    2f
-1:      movq  VCPU_domain(%rbx),%rdi
+UNLIKELY_START(z, sysenter_gpf)
+        movl  $TRAP_gp_fault,UREGS_entry_vector(%rsp)
+        subq  $2,UREGS_rip(%rsp)
+        movl  %eax,TRAPBOUNCE_error_code(%rdx)
+        movq  VCPU_gp_fault_addr(%rbx),%rax
+        testb $4,VCPU_gp_fault_flags(%rbx)
+        setnz %cl
+        leal  TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx
+UNLIKELY_END(sysenter_gpf)
+        movq  VCPU_domain(%rbx),%rdi
         movq  %rax,TRAPBOUNCE_eip(%rdx)
         movb  %cl,TRAPBOUNCE_flags(%rdx)
         testb $1,DOMAIN_is_32bit_pv(%rdi)
         jnz   compat_sysenter
-        call  create_bounce_frame
-        jmp   test_all_events
-2:      movl  %eax,TRAPBOUNCE_error_code(%rdx)
-        movq  VCPU_gp_fault_addr(%rbx),%rax
-        movb  $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl
-        movl  $TRAP_gp_fault,UREGS_entry_vector(%rsp)
-        jmp   1b
+        jmp   .Lbounce_exception
 
 ENTRY(int80_direct_trap)
         pushq $0
@@ -482,6 +495,7 @@ 1:      movq  %rsp,%rdi
         jnz   compat_post_handle_exception
         testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx)
         jz    test_all_events
+.Lbounce_exception:
         call  create_bounce_frame
         movb  $0,TRAPBOUNCE_flags(%rdx)
         jmp   test_all_events