Merge tag 'for-linus-5.17' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fix from Paolo Bonzini:
"Fix for the SLS mitigation, which makes a 'SETcc/RET' pair grow
to 'SETcc/RET/INT3'.
This doesn't fit in 4 bytes any more, so the alignment has to
change to 8 for this case"
* tag 'for-linus-5.17' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm/emulate: Fix SETcc emulation function offsets with SLS
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 5719d8c..e86d610 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -429,8 +429,23 @@
FOP_END
/* Special case for SETcc - 1 instruction per cc */
+
+/*
+ * Depending on .config the SETcc functions look like:
+ *
+ * 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.
+ */
+#define SETCC_LENGTH (4 + IS_ENABLED(CONFIG_SLS))
+#define SETCC_ALIGN (4 << IS_ENABLED(CONFIG_SLS))
+static_assert(SETCC_LENGTH <= SETCC_ALIGN);
+
#define FOP_SETCC(op) \
- ".align 4 \n\t" \
+ ".align " __stringify(SETCC_ALIGN) " \n\t" \
".type " #op ", @function \n\t" \
#op ": \n\t" \
#op " %al \n\t" \
@@ -1047,7 +1062,7 @@
static __always_inline u8 test_cc(unsigned int condition, unsigned long flags)
{
u8 rc;
- void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
+ void (*fop)(void) = (void *)em_setcc + SETCC_ALIGN * (condition & 0xf);
flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
asm("push %[flags]; popf; " CALL_NOSPEC
