[Xen-devel] [PATCH] x86-64 exception frame alignment

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

When generating an exception frame for injection into a guest, that
frame's
base should be aligned on a 16-byte boundary (as is done by the
hardware).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- src/xen/2005-08-29/xen/arch/x86/x86_64/entry.S      2005-08-29
14:29:56.000000000 +0200
+++ cpp/xen/2005-08-29/xen/arch/x86/x86_64/entry.S      2005-08-29
17:17:40.304663936 +0200
@@ -339,6 +339,7 @@ create_bounce_frame:
 1:      /* In kernel context already: push new frame at existing %rsp.
*/
         movq  UREGS_rsp+8(%rsp),%rsi
         andb  $0xfc,UREGS_cs+8(%rsp)    # Indicate kernel context to
guest.
+        andq  $~0xf,%rsi                # Align frame like hardware
would.
 2:      movq  $HYPERVISOR_VIRT_START,%rax
         cmpq  %rax,%rsi
         jb    1f                        # In +ve address space? Then
okay.

Attachment: xen-x86_64-exception-frame-align.patch
Description: Binary data

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