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 5.10-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-5.10 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-owner@xxxxxxxxxxxxxxx Wed May 10 20:16:44 2023
From: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
Date: Wed, 10 May 2023 18:15:47 +0000
Subject: KVM: x86: move guest_pv_has out of user_access section
To: <gregkh@xxxxxxxxxxxxxxxxxxx>, <stable@xxxxxxxxxxxxxxx>
Cc: <lee@xxxxxxxxxx>, <seanjc@xxxxxxxxxx>, <kvm@xxxxxxxxxxxxxxx>, <bp@xxxxxxxxx>, <mingo@xxxxxxxxxx>, <tglx@xxxxxxxxxxxxx>, <pbonzini@xxxxxxxxxx>, <vkuznets@xxxxxxxxxx>, <wanpengli@xxxxxxxxxxx>, <jmattson@xxxxxxxxxx>, <joro@xxxxxxxxxx>, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>, David Woodhouse <dwmw2@xxxxxxxxxxxxx>, "Rishabh Bhatnagar" <risbhat@xxxxxxxxxx>, Allen Pais <apais@xxxxxxxxxxxxxxxxxxx>
Message-ID: <20230510181547.22451-10-risbhat@xxxxxxxxxx>
From: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
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: Rishabh Bhatnagar <risbhat@xxxxxxxxxx>
Tested-by: Allen Pais <apais@xxxxxxxxxxxxxxxxxxx>
Acked-by: Sean Christopherson <seanjc@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
@@ -3049,9 +3049,6 @@ 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.
@@ -3060,6 +3057,9 @@ 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"
@@ -3082,6 +3082,9 @@ 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 stable-owner@xxxxxxxxxxxxxxx are
queue-5.10/kvm-fix-steal-time-asm-constraints.patch
queue-5.10/kvm-x86-ensure-pv-tlb-flush-tracepoint-reflects-kvm-behavior.patch
queue-5.10/blk-crypto-make-blk_crypto_evict_key-more-robust.patch
queue-5.10/kvm-x86-do-not-report-preemption-if-the-steal-time-cache-is-stale.patch
queue-5.10/kvm-x86-do-not-set-st-preempted-when-going-back-to-user-space.patch
queue-5.10/kvm-x86-move-guest_pv_has-out-of-user_access-section.patch
queue-5.10/kvm-x86-fix-recording-of-guest-steal-time-preempted-status.patch
queue-5.10/blk-mq-release-crypto-keyslot-before-reporting-i-o-complete.patch
queue-5.10/kvm-x86-revalidate-steal-time-cache-if-msr-value-changes.patch
queue-5.10/blk-crypto-make-blk_crypto_evict_key-return-void.patch
queue-5.10/kvm-x86-remove-obsolete-disabling-of-page-faults-in-kvm_arch_vcpu_put.patch
