[Xen-devel] [PATCH] x86: drop register reload from INT80 malicious MSI guard

["Jan Beulich" <JBeulich@xxxxxxxx>]

None of the restored registers are actually of interest to the
subsequent code (as opposed to the similar construct on the compat
mode hypercall path).

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

--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -286,7 +286,6 @@ ENTRY(int80_direct_trap)
 UNLIKELY_START(ne, msi_check)
         movl  $0x80,%edi
         call  check_for_unexpected_msi
-        LOAD_C_CLOBBERED
 UNLIKELY_END(msi_check)
 
         GET_CURRENT(%rbx)

Attachment: x86-drop-reg-reload.patch
Description: Text document

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