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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.googlemail.com with ESMTPSA id y19sm6826046edc.17.2021.12.13.06.22.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Dec 2021 06:22:09 -0800 (PST) Sender: Paolo Bonzini Message-ID: <72bf0b09-6383-d5cd-e719-dcd036b49834@redhat.com> Date: Mon, 13 Dec 2021 15:22:07 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH MANUALSEL 5.10 4/4] KVM: downgrade two BUG_ONs to WARN_ON_ONCE Content-Language: en-US To: Sasha Levin , linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: kvm@vger.kernel.org References: <20211213142020.352376-1-sashal@kernel.org> <20211213142020.352376-4-sashal@kernel.org> From: Paolo Bonzini In-Reply-To: <20211213142020.352376-4-sashal@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/13/21 15:20, Sasha Levin wrote: > From: Paolo Bonzini > > [ Upstream commit 5f25e71e311478f9bb0a8ef49e7d8b95316491d7 ] > > This is not an unrecoverable situation. Users of kvm_read_guest_offset_cached > and kvm_write_guest_offset_cached must expect the read/write to fail, and > therefore it is possible to just return early with an error value. > > Signed-off-by: Paolo Bonzini > Signed-off-by: Sasha Levin > --- > virt/kvm/kvm_main.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 97ac3c6fd4441..4a7d377b3a500 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2590,7 +2590,8 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, > int r; > gpa_t gpa = ghc->gpa + offset; > > - BUG_ON(len + offset > ghc->len); > + if (WARN_ON_ONCE(len + offset > ghc->len)) > + return -EINVAL; > > if (slots->generation != ghc->generation) { > if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) > @@ -2627,7 +2628,8 @@ int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, > int r; > gpa_t gpa = ghc->gpa + offset; > > - BUG_ON(len + offset > ghc->len); > + if (WARN_ON_ONCE(len + offset > ghc->len)) > + return -EINVAL; > > if (slots->generation != ghc->generation) { > if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len)) > Acked-by: Paolo Bonzini