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AJvYcCX+e6z70SX7f1Q63qiu32/jF25UKDdY/6OOt0kbrwQ1mvSXJGb2ntKXhhHsmeDpkjKQH2WJEfLiELnmV1s=@vger.kernel.org X-Gm-Message-State: AOJu0YwprO9vtj14tO2eutPNwulpdfvahyylNqDBVX3MOc9by/Yh39LX KPsZSqVHUCIScCZ8Lhlne49yRQ07oxyNXHWoTGW0VZ3/2z6wWziXpCpZ4SMKYVuDwKfi50S9JUp yCA== X-Google-Smtp-Source: AGHT+IGhD298IRUsLbG9Vvh3RdM0kkLkILPxgLrIWMIoqbOrQ1gdjDJKJGI8q2+JSljRFS1PTXtfwLhkpEg= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:da87:b0:206:a1aa:2673 with SMTP id d9443c01a7336-206a1aa2ademr990845ad.1.1725382735076; Tue, 03 Sep 2024 09:58:55 -0700 (PDT) Date: Tue, 3 Sep 2024 09:58:53 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240802195120.325560-1-seanjc@google.com> <20240802195120.325560-2-seanjc@google.com> Message-ID: Subject: Re: [PATCH 1/5] KVM: x86: Re-enter guest if WRMSR(X2APIC_ICR) fastpath is successful From: Sean Christopherson To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Tue, Sep 03, 2024, Paolo Bonzini wrote: > On Tue, Sep 3, 2024 at 5:09=E2=80=AFPM Sean Christopherson wrote: > > On Mon, Sep 02, 2024, Paolo Bonzini wrote: > > > On Fri, Aug 2, 2024 at 9:51=E2=80=AFPM Sean Christopherson wrote: > > > > Re-enter the guest in the fastpath if WRMSR emulation for x2APIC's = ICR is > > > > successful, as no additional work is needed, i.e. there is no code = unique > > > > for WRMSR exits between the fastpath and the "!=3D EXIT_FASTPATH_NO= NE" check > > > > in __vmx_handle_exit(). > > > > > > What about if you send an IPI to yourself? Doesn't that return true > > > for kvm_vcpu_exit_request() if posted interrupts are disabled? > > > > Yes, but that doesn't have anything to do with WRMSR itself, as KVM nee= ds to morph > > EXIT_FASTPATH_EXIT_HANDLED =3D> EXIT_FASTPATH_REENTER_GUEST if there's = a pending > > event that needs requires injection. >=20 > The other way round? i.e. treat EXIT_FASTPATH_REENTER_GUEST as > EXIT_FASTPATH_EXIT_HANDLED to go through event injection. Doh, yes.