From fb58e9a26c3ce0278d8118fc2a70e6d528967f42 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 12 Nov 2021 02:53:41 -0500 Subject: [PATCH] KVM: x86: move guest_pv_has out of user_access section 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 Cc: David Woodhouse Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- 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 54a45496b59e1..3de93d4bf16ba 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3227,9 +3227,6 @@ 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. @@ -3238,6 +3235,9 @@ 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" @@ -3260,6 +3260,9 @@ 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; } -- 2.30.2