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KVM: x86: move guest_pv_has out of user_access section

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From: Paolo Bonzini <pbonzini@redhat.com>

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@canb.auug.org.au>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
Tested-by: Allen Pais <apais@linux.microsoft.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rishabh Bhatnagar 2023-05-10 18:15:47 +00:00 committed by Greg Kroah-Hartman
parent 85cfbaa575
commit fcfe05990a
1 changed files with 6 additions and 3 deletions
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9
arch/x86/kvm/x86.c
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@ -3049,9 +3049,6 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
} }
st = (struct kvm_steal_time __user *)ghc->hva; 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 * Doing a TLB flush here, on the guest's behalf, can avoid
* expensive IPIs. * expensive IPIs.
@ -3060,6 +3057,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
u8 st_preempted = 0; u8 st_preempted = 0;
int err = -EFAULT; int err = -EFAULT;
if (!user_access_begin(st, sizeof(*st)))
return;
asm volatile("1: xchgb %0, %2\n" asm volatile("1: xchgb %0, %2\n"
"xor %1, %1\n" "xor %1, %1\n"
"2:\n" "2:\n"
@ -3082,6 +3082,9 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
if (!user_access_begin(st, sizeof(*st))) if (!user_access_begin(st, sizeof(*st)))
goto dirty; goto dirty;
} else { } else {
if (!user_access_begin(st, sizeof(*st)))
return;
unsafe_put_user(0, &st->preempted, out); unsafe_put_user(0, &st->preempted, out);
vcpu->arch.st.preempted = 0; vcpu->arch.st.preempted = 0;
} }