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AHgh+Rr1kS4nY7RnEkZhIUuyBKrDT2AjEGDbCwgZ2CQ/JO4LnTgXy21NmhPUVkoMCLts0HRCJJMCtus=@vger.kernel.org X-Gm-Message-State: AOJu0Yzg8menQoXxqAlHiz9fJM3nR/6u1WqxV1sp5ZI0QQxpdy0992aO OJMi4NsZhVj4v0FpbF5NDHFwYOQF5422CRO9BlSryILzvPI6XIxxpBPDHx88KoDNHahLpDjPBAT ZV6t2VQ== X-Received: from plbjx15.prod.google.com ([2002:a17:903:138f:b0:2c6:a589:6022]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:ea11:b0:2c8:25c8:85a6 with SMTP id d9443c01a7336-2ca2d52e7a1mr31713865ad.2.1782831227796; Tue, 30 Jun 2026 07:53:47 -0700 (PDT) Date: Tue, 30 Jun 2026 07:53:47 -0700 In-Reply-To: <20260626193343.256956-4-jinpu.wang@ionos.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260626193343.256956-1-jinpu.wang@ionos.com> <20260626193343.256956-4-jinpu.wang@ionos.com> Message-ID: Subject: Re: [stable-6.12 v2 3/3] KVM: SEV: Ignore Port I/O requests of length '0' From: Sean Christopherson To: Jack Wang Cc: gregkh@linuxfoundation.org, sashal@kernel.org, stable@vger.kernel.org, Tom Lendacky , Paolo Bonzini Content-Type: text/plain; charset="us-ascii" On Fri, Jun 26, 2026, Jack Wang wrote: > From: Sean Christopherson > > commit 3988bd2723de407ae90fa7a6f6029b4e60238c58 upstream. > > Explicitly ignore Port I/O requests of length '0' (or count '0'), so that > setting up the software scratch area (and other code) doesn't have to > worry about underflowing the length, and to allow for WARNing on trying > to configure the scratch area with len==0. > > Fixes: 291bd20d5d88 ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT") > Cc: stable@vger.kernel.org > Reviewed-by: Tom Lendacky > Signed-off-by: Sean Christopherson > Message-ID: <20260501202250.2115252-5-seanjc@google.com> > Signed-off-by: Paolo Bonzini > Signed-off-by: Jack Wang > --- Acked-by: Sean Christopherson