linux-kernel - [PATCH] x86/tsx: clear RTM and HLE when MSR_IA32_TSX

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Message-ID: <CAPm50aJyfxobKhTrS=dC3pQmM5EbwY2xunet3X5XgnnFUEMmBA@mail.gmail.com>
Date:   Mon, 6 Sep 2021 10:46:05 +0800
From:   Hao Peng <flyingpenghao@...il.com>
To:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] x86/tsx: clear RTM and HLE when MSR_IA32_TSX_CTRL is not supported

If hypervisor does not support MSR_IA32_TSX_CTRL, but guest supports
RTM and HLE features, it will affect TAA mitigation.

Signed-off-by: Peng Hao <flyingpeng@...cent.com>
---
 arch/x86/kernel/cpu/tsx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/cpu/tsx.c b/arch/x86/kernel/cpu/tsx.c
index 9c7a5f049292..5e852c14fef2 100644
--- a/arch/x86/kernel/cpu/tsx.c
+++ b/arch/x86/kernel/cpu/tsx.c
@@ -122,6 +122,13 @@ void __init tsx_init(void)

        if (!tsx_ctrl_is_supported()) {
                tsx_ctrl_state = TSX_CTRL_NOT_SUPPORTED;
+
+               /* If hypervisor does not support MSR_IA32_TSX_CTRL emulation,
+                * but guest supports RTM and HLE features, it will affect TAA
+                * （tsx_async_abort）mitigation.
+                */
+               setup_clear_cpu_cap(X86_FEATURE_RTM);
+               setup_clear_cpu_cap(X86_FEATURE_HLE);
                return;
        }

--
2.27.0