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Subject[tip: x86/core] kvm/emulate: Fix SETcc emulation for ENDBR
The following commit has been merged into the x86/core branch of tip:

Commit-ID: 44aba1d9e26641728f33f5834f436dd9ef486b96
Gitweb: https://git.kernel.org/tip/44aba1d9e26641728f33f5834f436dd9ef486b96
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Mon, 21 Mar 2022 10:13:12 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 21 Mar 2022 10:57:52 +01:00

kvm/emulate: Fix SETcc emulation for ENDBR

Companion patch for commit fe83f5eae432 ("kvm/emulate: Fix SETcc
emulation function offsets with SLS"), now extending it to cover the
additional ENDBR instruction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/YjMVpfe%2f9ldmWX8W@hirez.programming.kicks-ass.net
---
arch/x86/kvm/emulate.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d98fb36..df5e6c0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -24,6 +24,7 @@
#include <linux/stringify.h>
#include <asm/debugreg.h>
#include <asm/nospec-branch.h>
+#include <asm/ibt.h>

#include "x86.h"
#include "tss.h"
@@ -434,15 +435,16 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
/*
* Depending on .config the SETcc functions look like:
*
+ * ENDBR [4 bytes; CONFIG_X86_KERNEL_IBT]
* SETcc %al [3 bytes]
* RET [1 byte]
* INT3 [1 byte; CONFIG_SLS]
*
- * Which gives possible sizes 4 or 5. When rounded up to the
- * next power-of-two alignment they become 4 or 8.
+ * Which gives possible sizes 4, 5, 8 or 9. When rounded up to the
+ * next power-of-two alignment they become 4, 8 or 16 resp.
*/
-#define SETCC_LENGTH (4 + IS_ENABLED(CONFIG_SLS))
-#define SETCC_ALIGN (4 << IS_ENABLED(CONFIG_SLS))
+#define SETCC_LENGTH (ENDBR_INSN_SIZE + 4 + IS_ENABLED(CONFIG_SLS))
+#define SETCC_ALIGN (4 << IS_ENABLED(CONFIG_SLS) << HAS_KERNEL_IBT)
static_assert(SETCC_LENGTH <= SETCC_ALIGN);

#define FOP_SETCC(op) \
\
 
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