The XOR instruction affects the carry and zero flag. Move it before

the VM instructions so that SETNA propagates the error condition
of the latter.  Avoids "cpu0: failed to enter VMM mode" errors.
Fixes previous commit.
tested by Hrvoje; OK dv@

diff --git a/sys/arch/amd64/amd64/vmm_support.S b/sys/arch/amd64/amd64/vmm_support.S
index cb500f5..b3c9e5d 100644 (file)
--- a/sys/arch/amd64/amd64/vmm_support.S
+++ b/sys/arch/amd64/amd64/vmm_support.S
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vmm_support.S,v 1.19 2022/04/09 01:49:43 dv Exp $     */
+/*     $OpenBSD: vmm_support.S,v 1.20 2022/04/14 20:24:15 bluhm Exp $  */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -62,8 +62,8 @@ _C_LABEL(vmm_dispatch_intr):
 
 _C_LABEL(vmxon):
        RETGUARD_SETUP(vmxon, r11)
-       vmxon   (%rdi)
        xorq    %rax, %rax
+       vmxon   (%rdi)
        setna   %al
        RETGUARD_CHECK(vmxon, r11)
        ret
@@ -71,8 +71,8 @@ _C_LABEL(vmxon):
 
 _C_LABEL(vmxoff):
        RETGUARD_SETUP(vmxoff, r11)
-       vmxoff
        xorq    %rax, %rax
+       vmxoff
        setna   %al
        RETGUARD_CHECK(vmxoff, r11)
        ret
@@ -80,8 +80,8 @@ _C_LABEL(vmxoff):
 
 _C_LABEL(vmclear):
        RETGUARD_SETUP(vmclear, r11)
-       vmclear (%rdi)
        xorq    %rax, %rax
+       vmclear (%rdi)
        setna   %al
        RETGUARD_CHECK(vmclear, r11)
        ret
@@ -89,8 +89,8 @@ _C_LABEL(vmclear):
 
 _C_LABEL(vmptrld):
        RETGUARD_SETUP(vmptrld, r11)
-       vmptrld (%rdi)
        xorq    %rax, %rax
+       vmptrld (%rdi)
        setna   %al
        RETGUARD_CHECK(vmptrld, r11)
        ret
@@ -98,8 +98,8 @@ _C_LABEL(vmptrld):
 
 _C_LABEL(vmptrst):
        RETGUARD_SETUP(vmptrst, r11)
-       vmptrst (%rdi)
        xorq    %rax, %rax
+       vmptrst (%rdi)
        setna   %al
        RETGUARD_CHECK(vmptrst, r11)
        ret
@@ -107,8 +107,8 @@ _C_LABEL(vmptrst):
 
 _C_LABEL(vmwrite):
        RETGUARD_SETUP(vmwrite, r11)
-       vmwrite %rsi, %rdi
        xorq    %rax, %rax
+       vmwrite %rsi, %rdi
        setna   %al
        RETGUARD_CHECK(vmwrite, r11)
        ret
@@ -116,8 +116,8 @@ _C_LABEL(vmwrite):
 
 _C_LABEL(vmread):
        RETGUARD_SETUP(vmread, r11)
-       vmread  %rdi, (%rsi)
        xorq    %rax, %rax
+       vmread  %rdi, (%rsi)
        setna   %al
        RETGUARD_CHECK(vmread, r11)
        ret