linux-kernel - [PATCH] KVM: x86: emulate reserved nops from 0f/18 to 0f/1f

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200515161919.29249-1-pbonzini@redhat.com>
Date:   Fri, 15 May 2020 12:19:19 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH] KVM: x86: emulate reserved nops from 0f/18 to 0f/1f

Instructions starting with 0f18 up to 0f1f are reserved nops, except those
that were assigned to MPX.  These include the endbr markers used by CET.
List them correctly in the opcode table.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/emulate.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index de5476f8683e..d0e2825ae617 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4800,8 +4800,12 @@ static const struct opcode twobyte_table[256] = {
 	GP(ModRM | DstReg | SrcMem | Mov | Sse, &pfx_0f_10_0f_11),
 	GP(ModRM | DstMem | SrcReg | Mov | Sse, &pfx_0f_10_0f_11),
 	N, N, N, N, N, N,
-	D(ImplicitOps | ModRM | SrcMem | NoAccess),
-	N, N, N, N, N, N, D(ImplicitOps | ModRM | SrcMem | NoAccess),
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 4 * prefetch + 4 * reserved NOP */
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N,
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 8 * reserved NOP */
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 8 * reserved NOP */
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 8 * reserved NOP */
+	D(ImplicitOps | ModRM | SrcMem | NoAccess), /* NOP + 7 * reserved NOP */
 	/* 0x20 - 0x2F */
 	DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read),
 	DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),
-- 
2.18.2