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authorJosh Poimboeuf <jpoimboe@kernel.org>2022-06-14 23:16:13 +0200
committerBorislav Petkov <bp@suse.de>2022-06-27 10:34:00 +0200
commitfc02735b14fff8c6678b521d324ade27b1a3d4cf (patch)
tree9be32b1a805858cab02c043a740b2bab8f45a15c /arch/x86/kernel/cpu
parentbb06650634d3552c0f8557e9d16aa1a408040e28 (diff)
KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS
On eIBRS systems, the returns in the vmexit return path from __vmx_vcpu_run() to vmx_vcpu_run() are exposed to RSB poisoning attacks. Fix that by moving the post-vmexit spec_ctrl handling to immediately after the vmexit. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/bugs.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index efff8b9f1bbd..31ccb7852afd 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -195,6 +195,10 @@ void __init check_bugs(void)
#endif
}
+/*
+ * NOTE: For VMX, this function is not called in the vmexit path.
+ * It uses vmx_spec_ctrl_restore_host() instead.
+ */
void
x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
{