[Xen-changelog] [xen staging] x86/HVM: ignore guest INVD uses

[patchbot@xxxxxxx]

commit 4d4fec207b472a7483483b99c3d94537b06cddad
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Sep 3 14:49:20 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 3 14:49:20 2019 +0200

    x86/HVM: ignore guest INVD uses
    
    The only place we'd expect the insn to be sensibly used is in
    (virtualization unaware) firmware.
    
    Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/emulate.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index b61faf704b..7cd727ab97 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -2210,11 +2210,18 @@ static int hvmemul_cache_op(
 
         hvmemul_unmap_linear_addr(mapping, addr, 0, hvmemul_ctxt);
         /* fall through */
-    case x86emul_invd:
     case x86emul_wbinvd:
     case x86emul_wbnoinvd:
         alternative_vcall(hvm_funcs.wbinvd_intercept);
         break;
+
+    case x86emul_invd:
+        /*
+         * Deliberately ignored: We mustn't issue INVD, and issuing WBINVD
+         * wouldn't match the request. And the only place we'd expect the insn
+         * to be sensibly used is in (virtualization unaware) firmware.
+         */
+        break;
     }
 
     return X86EMUL_OKAY;
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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