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KVM: x86: move guest_pv_has out of user_access section

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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@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2021-11-12 02:53:41 -05:00
parent f5396f2d82
commit 3e067fd850
1 changed files with 6 additions and 3 deletions
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9
arch/x86/kvm/x86.c
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@ -3292,9 +3292,6 @@ 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.
@ -3303,6 +3300,9 @@ 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"
@ -3325,6 +3325,9 @@ 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;
}