From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: pbonzini@redhat.com, rkrcmar@redhat.com, joro@8bytes.org,
jon.grimm@amd.com,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Alex Williamson <alex.williamson@redhat.com>
Subject: [PATCH] kvm: x86: svm: Fix NULL pointer dereference when AVIC not enabled
Date: Fri, 21 Feb 2020 08:52:17 -0600 [thread overview]
Message-ID: <1582296737-13086-1-git-send-email-suravee.suthikulpanit@amd.com> (raw)
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: 8937d762396d ("kvm: x86: svm: Add support to (de)activate posted interrupts.")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
---
arch/x86/kvm/svm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 19035fb..1858455 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5222,6 +5222,9 @@ static void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
struct vmcb *vmcb = svm->vmcb;
bool activated = kvm_vcpu_apicv_active(vcpu);
+ if (!avic)
+ return;
+
if (activated) {
/**
* During AVIC temporary deactivation, guest could update
--
1.8.3.1
next reply other threads:[~2020-02-21 14:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 14:52 Suravee Suthikulpanit [this message]
2020-02-21 15:39 ` [PATCH] kvm: x86: svm: Fix NULL pointer dereference when AVIC not enabled Alex Williamson
2020-02-21 16:04 ` Paolo Bonzini
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