x86emul: skip VIF processing in VME mode for 16-bit POPF at IOPL 3

At IOPL 3 CR4.VME is irrelevant.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c
index 0ae433538e5954d37823021ec98b7018aa801579..5313145b63477e5231d6add68ef65439f3d7dff9 100644 (file)
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -4223,7 +4223,8 @@ x86_emulate(
         if ( op_bytes == 2 )
         {
             dst.val = (uint16_t)dst.val | (_regs.eflags & 0xffff0000u);
-            if ( cr4 & X86_CR4_VME )
+            if ( (cr4 & X86_CR4_VME) &&
+                 MASK_EXTR(_regs.eflags, X86_EFLAGS_IOPL) != 3 )
             {
                 if ( dst.val & X86_EFLAGS_IF )
                 {