Re: [PATCH] KVM: x86: move guest_pv_has out of user_access section

From: David Woodhouse
Date: Fri Nov 12 2021 - 03:11:15 EST


On Fri, 2021-11-12 at 02:54 -0500, Paolo Bonzini wrote:
> 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>

Acked-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

Thanks. I found a bunch of those objtool warnings during my original
experimentation and testing, but clearly missed that one. I'll turn on
CONFIG_UBSAN.


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