kvm: x86: svm: Fix NULL pointer dereference when AVIC not enabled
Launching VM w/ AVIC disabled together with pass-through device results in NULL pointer dereference bug with the following call trace. RIP: 0010:svm_refresh_apicv_exec_ctrl+0x17e/0x1a0 [kvm_amd] Call Trace: kvm_vcpu_update_apicv+0x44/0x60 [kvm] kvm_arch_vcpu_ioctl_run+0x3f4/0x1c80 [kvm] kvm_vcpu_ioctl+0x3d8/0x650 [kvm] do_vfs_ioctl+0xaa/0x660 ? tomoyo_file_ioctl+0x19/0x20 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x57/0x190 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Investigation shows that this is due to the uninitialized usage of struct vapu_svm.ir_list in the svm_set_pi_irte_mode(), which is called from svm_refresh_apicv_exec_ctrl(). The ir_list is initialized only if AVIC is enabled. So, fixes by adding a check if AVIC is enabled in the svm_refresh_apicv_exec_ctrl(). Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206579 Fixes: 8937d762 ("kvm: x86: svm: Add support to (de)activate posted interrupts.") Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com> Tested-by: NAlex Williamson <alex.williamson@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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