diff options
| author | Yuan ZhaoXiong | 2022-12-02 20:36:14 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-01-07 11:11:47 +0100 |
| commit | 59cc9627be2577d1701a2d1248c38c6ca9e46323 (patch) | |
| tree | 5615ce56782b35f7b9bc0ab49876be013159cd78 /arch | |
| parent | 04066fcbf18eaa8747b8e7560d318b669e676503 (diff) | |
KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself
commit ef40757743b47cc95de9b4ed41525c94f8dc73d9 upstream.
When a VM reboots itself, the reset process will result in
an ioctl(KVM_SET_LAPIC, ...) to disable x2APIC mode and set
the xAPIC id of the vCPU to its default value, which is the
vCPU id.
That will be handled in KVM as follows:
kvm_vcpu_ioctl_set_lapic
kvm_apic_set_state
kvm_lapic_set_base => disable X2APIC mode
kvm_apic_state_fixup
kvm_lapic_xapic_id_updated
kvm_xapic_id(apic) != apic->vcpu->vcpu_id
kvm_set_apicv_inhibit(APICV_INHIBIT_REASON_APIC_ID_MODIFIED)
memcpy(vcpu->arch.apic->regs, s->regs, sizeof(*s)) => update APIC_ID
When kvm_apic_set_state invokes kvm_lapic_set_base to disable
x2APIC mode, the old 32-bit x2APIC id is still present rather
than the 8-bit xAPIC id. kvm_lapic_xapic_id_updated will set the
APICV_INHIBIT_REASON_APIC_ID_MODIFIED bit and disable APICv/x2AVIC.
Instead, kvm_lapic_xapic_id_updated must be called after APIC_ID is
changed.
In fact, this fixes another small issue in the code in that
potential changes to a vCPU's xAPIC ID need not be tracked for
KVM_GET_LAPIC.
Fixes: 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base")
Signed-off-by: Yuan ZhaoXiong <yuanzhaoxiong@baidu.com>
Message-Id: <1669984574-32692-1-git-send-email-yuanzhaoxiong@baidu.com>
Cc: stable@vger.kernel.org
Reported-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index d7639d126e6c..bf5ce862c4da 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2722,8 +2722,6 @@ static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu, icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR); __kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32); } - } else { - kvm_lapic_xapic_id_updated(vcpu->arch.apic); } return 0; @@ -2759,6 +2757,9 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s) } memcpy(vcpu->arch.apic->regs, s->regs, sizeof(*s)); + if (!apic_x2apic_mode(apic)) + kvm_lapic_xapic_id_updated(apic); + atomic_set_release(&apic->vcpu->kvm->arch.apic_map_dirty, DIRTY); kvm_recalculate_apic_map(vcpu->kvm); kvm_apic_set_version(vcpu); |