This is a note to let you know that I've just added the patch titled
KVM: x86: move guest_pv_has out of user_access section
to the 5.14-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:
kvm-x86-move-guest_pv_has-out-of-user_access-section.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3e067fd8503d6205aa0c1c8f48f6b209c592d19c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Date: Fri, 12 Nov 2021 02:53:41 -0500
Subject: KVM: x86: move guest_pv_has out of user_access section
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
commit 3e067fd8503d6205aa0c1c8f48f6b209c592d19c upstream.
When UBSAN is enabled, the code emitted for the call to guest_pv_has
includes a call to __ubsan_handle_load_invalid_value. objtool
complains that this call happens with UACCESS enabled; to avoid
the warning, pull the calls to user_access_begin into both arms
of the "if" statement, after the check for guest_pv_has.
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3222,9 +3222,6 @@ static void record_steal_time(struct kvm
}
st = (struct kvm_steal_time __user *)ghc->hva;
- if (!user_access_begin(st, sizeof(*st)))
- return;
-
/*
* Doing a TLB flush here, on the guest's behalf, can avoid
* expensive IPIs.
@@ -3233,6 +3230,9 @@ static void record_steal_time(struct kvm
u8 st_preempted = 0;
int err = -EFAULT;
+ if (!user_access_begin(st, sizeof(*st)))
+ return;
+
asm volatile("1: xchgb %0, %2\n"
"xor %1, %1\n"
"2:\n"
@@ -3255,6 +3255,9 @@ static void record_steal_time(struct kvm
if (!user_access_begin(st, sizeof(*st)))
goto dirty;
} else {
+ if (!user_access_begin(st, sizeof(*st)))
+ return;
+
unsafe_put_user(0, &st->preempted, out);
vcpu->arch.st.preempted = 0;
}
Patches currently in stable-queue which might be from pbonzini@xxxxxxxxxx are
queue-5.14/kvm-vmx-unregister-posted-interrupt-wakeup-handler-on-hardware-unsetup.patch
queue-5.14/selftests-kvm-fix-mismatched-fclose-after-popen.patch
queue-5.14/kvm-selftests-fix-nested-svm-tests-when-built-with-c.patch
queue-5.14/kvm-nvmx-handle-dynamic-msr-intercept-toggling.patch
queue-5.14/kvm-nvmx-query-current-vmcs-when-determining-if-msr-bitmaps-are-in-use.patch
queue-5.14/x86-irq-ensure-pi-wakeup-handler-is-unregistered-before-module-unload.patch
queue-5.14/kvm-x86-move-guest_pv_has-out-of-user_access-section.patch
queue-5.14/kvm-x86-fix-recording-of-guest-steal-time-preempted-status.patch
queue-5.14/kvm-x86-add-helper-to-consolidate-core-logic-of-set_cpuid-2-flows.patch
