From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
tony.luck@intel.com, ak@linux.intel.com,
tim.c.chen@linux.intel.com
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
kvm@vger.kernel.org,
Alyssa Milburn <alyssa.milburn@linux.intel.com>,
Daniel Sneddon <daniel.sneddon@linux.intel.com>,
antonio.gomez.iglesias@linux.intel.com,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Subject: [PATCH 3/6] x86/entry_32: Add VERW just before userspace transition
Date: Fri, 20 Oct 2023 13:45:09 -0700 [thread overview]
Message-ID: <20231020-delay-verw-v1-3-cff54096326d@linux.intel.com> (raw)
In-Reply-To: <20231020-delay-verw-v1-0-cff54096326d@linux.intel.com>
As done for entry_64, add support for executing VERW late in exit to
user path for 32-bit mode.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
arch/x86/entry/entry_32.S | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 6e6af42e044a..bbf77d2aab2e 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -886,6 +886,9 @@ SYM_FUNC_START(entry_SYSENTER_32)
popfl
popl %eax
+ /* Mitigate CPU data sampling attacks .e.g. MDS */
+ USER_CLEAR_CPU_BUFFERS
+
/*
* Return back to the vDSO, which will pop ecx and edx.
* Don't bother with DS and ES (they already contain __USER_DS).
@@ -954,6 +957,9 @@ restore_all_switch_stack:
/* Restore user state */
RESTORE_REGS pop=4 # skip orig_eax/error_code
+
+ /* Mitigate CPU data sampling attacks .e.g. MDS */
+ USER_CLEAR_CPU_BUFFERS
.Lirq_return:
/*
* ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
@@ -1146,6 +1152,8 @@ SYM_CODE_START(asm_exc_nmi)
/* Not on SYSENTER stack. */
call exc_nmi
+ /* Mitigate CPU data sampling attacks .e.g. MDS */
+ USER_CLEAR_CPU_BUFFERS
jmp .Lnmi_return
.Lnmi_from_sysenter_stack:
--
2.34.1
next prev parent reply other threads:[~2023-10-20 20:45 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-20 20:44 [PATCH 0/6] Delay VERW Pawan Gupta
2023-10-20 20:44 ` [PATCH 1/6] x86/bugs: Add asm helpers for executing VERW Pawan Gupta
2023-10-20 23:13 ` Sean Christopherson
2023-10-21 1:00 ` Pawan Gupta
2023-10-20 23:55 ` [RESEND][PATCH " Andrew Cooper
2023-10-21 1:18 ` Pawan Gupta
2023-10-21 1:33 ` Andrew Cooper
2023-10-21 2:21 ` Pawan Gupta
2023-10-23 18:08 ` Josh Poimboeuf
2023-10-23 19:09 ` Pawan Gupta
2023-10-25 6:28 ` Pawan Gupta
2023-10-25 7:22 ` Peter Zijlstra
2023-10-25 7:52 ` Andrew Cooper
2023-10-25 8:02 ` Peter Zijlstra
2023-10-25 15:27 ` Pawan Gupta
[not found] ` <6439a094-23a6-4de3-aa41-bd033163e044@citrix.com>
2023-10-22 16:16 ` [PATCH " Peter Zijlstra
2023-10-20 20:45 ` [PATCH 2/6] x86/entry_64: Add VERW just before userspace transition Pawan Gupta
2023-10-23 18:22 ` Josh Poimboeuf
2023-10-23 19:13 ` Pawan Gupta
2023-10-23 19:17 ` Dave Hansen
2023-10-23 18:35 ` Josh Poimboeuf
2023-10-23 21:04 ` Pawan Gupta
2023-10-23 21:47 ` Josh Poimboeuf
2023-10-23 22:30 ` Pawan Gupta
2023-10-23 22:45 ` Dave Hansen
2023-10-24 0:00 ` Pawan Gupta
2023-10-20 20:45 ` Pawan Gupta [this message]
2023-10-20 23:49 ` [PATCH 3/6] x86/entry_32: " Andi Kleen
2023-10-21 1:28 ` Pawan Gupta
2023-10-20 20:45 ` [PATCH 4/6] x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key Pawan Gupta
2023-10-23 18:48 ` Josh Poimboeuf
2023-10-23 21:09 ` Pawan Gupta
2023-10-20 20:45 ` [PATCH 5/6] x86/bugs: Cleanup mds_user_clear Pawan Gupta
2023-10-23 8:51 ` Nikolay Borisov
2023-10-23 16:06 ` Pawan Gupta
2023-10-20 20:45 ` [PATCH 6/6] KVM: VMX: Move VERW closer to VMentry for MDS mitigation Pawan Gupta
2023-10-20 22:55 ` Sean Christopherson
2023-10-21 0:46 ` Pawan Gupta
2023-10-23 14:58 ` Sean Christopherson
2023-10-23 17:05 ` Pawan Gupta
2023-10-23 18:56 ` Josh Poimboeuf
2023-10-23 21:17 ` Pawan Gupta
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