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Sean Christopherson authored
Move the VMCB updates from avic_refresh_apicv_exec_ctrl() into avic_set_virtual_apic_mode() and invert the dependency being said functions to avoid calling avic_vcpu_{load,put}() and avic_set_pi_irte_mode() when "only" setting the virtual APIC mode. avic_set_virtual_apic_mode() is invoked from common x86 with preemption enabled, which makes avic_vcpu_{load,put}() unhappy. Luckily, calling those and updating IRTE stuff is unnecessary as the only reason avic_set_virtual_apic_mode() is called is to handle transitions between xAPIC and x2APIC that don't also toggle APICv activation. And if activation doesn't change, there's no need to fiddle with the physical APIC ID table or update IRTE. The "full" refresh is guaranteed to be called if activation changes in this case as the only call to the "set" path is: kvm_vcpu_update_apicv(vcpu); static_call_cond(kvm_x86_set_virtual_apic_mode)(vcpu); and kvm_vcpu_update_apicv() invokes the refresh if activation changes: if (apic->apicv_active == activate) goto out; apic->apicv_active = activate; kvm_apic_update_apicv(vcpu); static_call(kvm_x86_refresh_apicv_exec_ctrl)(vcpu); Rename the helper to reflect that it is also called during "refresh". WARNING: CPU: 183 PID: 49186 at arch/x86/kvm/svm/avic.c:1081 avic_vcpu_put+0xde/0xf0 [kvm_amd] CPU: 183 PID: 49186 Comm: stable Tainted: G O 6.0.0-smp--fcddbca45f0a-sink #34 Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 10.48.0 01/27/2022 RIP: 0010:avic_vcpu_put+0xde/0xf0 [kvm_amd] avic_refresh_apicv_exec_ctrl+0x142/0x1c0 [kvm_amd] avic_set_virtual_apic_mode+0x5a/0x70 [kvm_amd] kvm_lapic_set_base+0x149/0x1a0 [kvm] kvm_set_apic_base+0x8f/0xd0 [kvm] kvm_set_msr_common+0xa3a/0xdc0 [kvm] svm_set_msr+0x364/0x6b0 [kvm_amd] __kvm_set_msr+0xb8/0x1c0 [kvm] kvm_emulate_wrmsr+0x58/0x1d0 [kvm] msr_interception+0x1c/0x30 [kvm_amd] svm_invoke_exit_handler+0x31/0x100 [kvm_amd] svm_handle_exit+0xfc/0x160 [kvm_amd] vcpu_enter_guest+0x21bb/0x23e0 [kvm] vcpu_run+0x92/0x450 [kvm] kvm_arch_vcpu_ioctl_run+0x43e/0x6e0 [kvm] kvm_vcpu_ioctl+0x559/0x620 [kvm] Fixes: 05c4fe8c ("KVM: SVM: Refresh AVIC configuration when changing APIC mode") Cc: stable@vger.kernel.org Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20230106011306.85230-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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