This is a note to let you know that I've just added the patch titled
x86/entry_32: Add VERW just before userspace transition
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-entry_32-add-verw-just-before-userspace-transition.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable+bounces-27526-greg=kroah.com@xxxxxxxxxxxxxxx Tue Mar 12 22:11:07 2024
From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
Date: Tue, 12 Mar 2024 14:10:57 -0700
Subject: x86/entry_32: Add VERW just before userspace transition
To: stable@xxxxxxxxxxxxxxx
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Message-ID: <20240312-delay-verw-backport-5-15-y-v2-4-e0f71d17ed1b@xxxxxxxxxxxxxxx>
Content-Disposition: inline
From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
commit a0e2dab44d22b913b4c228c8b52b2a104434b0b3 upstream.
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@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-3-a6216d83edb7%40linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_32.S | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -912,6 +912,7 @@ 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.
@@ -981,6 +982,7 @@ 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
@@ -1173,6 +1175,7 @@ SYM_CODE_START(asm_exc_nmi)
/* Not on SYSENTER stack. */
call exc_nmi
+ CLEAR_CPU_BUFFERS
jmp .Lnmi_return
.Lnmi_from_sysenter_stack:
Patches currently in stable-queue which might be from kroah.com@xxxxxxxxxxxxxxx are
queue-5.15/x86-rfds-mitigate-register-file-data-sampling-rfds.patch
queue-5.15/x86-entry_32-add-verw-just-before-userspace-transition.patch
queue-5.15/x86-bugs-add-asm-helpers-for-executing-verw.patch
queue-5.15/kvm-x86-export-rfds_no-and-rfds_clear-to-guests.patch
queue-5.15/x86-asm-add-_asm_rip-macro-for-x86-64-rip-suffix.patch
queue-5.15/x86-entry_64-add-verw-just-before-userspace-transition.patch
queue-5.15/x86-mmio-disable-kvm-mitigation-when-x86_feature_clear_cpu_buf-is-set.patch
queue-5.15/x86-bugs-use-alternative-instead-of-mds_user_clear-static-key.patch
queue-5.15/documentation-hw-vuln-add-documentation-for-rfds.patch
queue-5.15/kvm-vmx-use-bt-jnc-i.e.-eflags.cf-to-select-vmresume-vs.-vmlaunch.patch
queue-5.15/kvm-vmx-move-verw-closer-to-vmentry-for-mds-mitigation.patch
