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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,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Nikolay Borisov <nik.borisov@suse.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  v6 3/6] x86/entry_32: Add VERW just before userspace transition
Date: Tue, 23 Jan 2024 23:41:36 -0800	[thread overview]
Message-ID: <20240123-delay-verw-v6-3-a8206baca7d3@linux.intel.com> (raw)
In-Reply-To: <20240123-delay-verw-v6-0-a8206baca7d3@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 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index c73047bf9f4b..fba427646805 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -885,6 +885,7 @@ SYM_FUNC_START(entry_SYSENTER_32)
 	BUG_IF_WRONG_CR3 no_user_check=1
 	popfl
 	popl	%eax
+	CLEAR_CPU_BUFFERS
 
 	/*
 	 * Return back to the vDSO, which will pop ecx and edx.
@@ -954,6 +955,7 @@ restore_all_switch_stack:
 
 	/* Restore user state */
 	RESTORE_REGS pop=4			# skip orig_eax/error_code
+	CLEAR_CPU_BUFFERS
 .Lirq_return:
 	/*
 	 * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
@@ -1146,6 +1148,7 @@ SYM_CODE_START(asm_exc_nmi)
 
 	/* Not on SYSENTER stack. */
 	call	exc_nmi
+	CLEAR_CPU_BUFFERS
 	jmp	.Lnmi_return
 
 .Lnmi_from_sysenter_stack:

-- 
2.34.1



  parent reply	other threads:[~2024-01-24  7:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-24  7:40 [PATCH v6 0/6] Delay VERW Pawan Gupta
2024-01-24  7:41 ` [PATCH v6 1/6] x86/bugs: Add asm helpers for executing VERW Pawan Gupta
2024-02-01  1:18   ` Pawan Gupta
2024-02-02  3:29   ` Josh Poimboeuf
2024-02-02 21:31     ` Pawan Gupta
2024-01-24  7:41 ` [PATCH v6 2/6] x86/entry_64: Add VERW just before userspace transition Pawan Gupta
2024-01-24  7:41 ` Pawan Gupta [this message]
2024-01-24  7:41 ` [PATCH v6 4/6] x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key Pawan Gupta
2024-01-24  7:42 ` [PATCH v6 5/6] KVM: VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH Pawan Gupta
2024-01-24  7:42 ` [PATCH v6 6/6] KVM: VMX: Move VERW closer to VMentry for MDS mitigation Pawan Gupta
2024-01-26 21:31   ` Sean Christopherson
2024-02-01  1:12     ` Pawan Gupta

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