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>
---
arch/x86/kvm/x86.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9e9298c333c8..e3599a51c72d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3042,9 +3042,6 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
}
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.
@@ -3053,6 +3050,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
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"
@@ -3075,6 +3075,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
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;
}
--
2.37.1
